Inclusion in Database Transactions

By design, custom plug-ins can only be registered in the non-transaction pre-event and post-event stages of the event execution pipeline. However, it is possible for a plug-in to execute within the Microsoft Dynamics CRM database transaction even though the plug-in was registered in a non-transaction pipeline stage.

If a plug-in is registered for execution in a child pipeline and that child pipeline is executed by a parent pipeline that has started a database transaction, any database modifications initiated by plug-in Web service method calls in the child pipeline are also included in the parent pipeline's database transaction. If the child pipeline plug-in throws an exception or does not catch a thrown exception, the entire transaction is rolled back and the parent pipeline core operation is canceled.

Note There is no property or class method provided in the Event Framework for a plug-in to determine at run time if it is executing in a database transaction.

A List of SMTP and POP3 Servers (Mail Server List)

Default Ports:

Server: Authentication: Port:
SMTP Server (Outgoing Messages) Non-Encrypted AUTH 25 (or 587)
  Secure (TLS) StartTLS 587
  Secure (SSL) SSL 465
POP3 Server (Incoming Messages) Non-Encrypted AUTH 110
  Secure (SSL) SSL 995

 

Googlemail - Gmail

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.gmail.com SSL 465
  smtp.gmail.com StartTLS 587
POP3 Server (Incoming Messages) pop.gmail.com SSL 995
  Please make sure, that POP3 access is enabled in the account settings.
Login to your account and enable POP3.

 

Outlook.com

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.live.com StartTLS 587
POP3 Server (Incoming Messages) pop3.live.com SSL 995

 

Yahoo Mail

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.mail.yahoo.com SSL 465
POP3 Server (Incoming Messages) pop.mail.yahoo.com SSL 995

 

Yahoo Mail Plus

Server: Authentication: Port:
SMTP Server (Outgoing Messages) plus.smtp.mail.yahoo.com SSL 465
POP3 Server (Incoming Messages) plus.pop.mail.yahoo.com SSL 995

 

Yahoo UK

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.mail.yahoo.co.uk SSL 465
POP3 Server (Incoming Messages) pop.mail.yahoo.co.uk SSL 995

 

Yahoo Deutschland

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.mail.yahoo.com SSL 465
POP3 Server (Incoming Messages) pop.mail.yahoo.com SSL 995

 

Yahoo AU/NZ

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.mail.yahoo.com.au SSL 465
POP3 Server (Incoming Messages) pop.mail.yahoo.com.au SSL 995

 

O2

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.o2.ie   25
POP3 Server (Incoming Messages) pop3.o2.ie   110

 

O2.uk

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.o2.co.uk   25
POP3 Server (Incoming Messages) pop3.o2.co.uk   110

 

AT&T

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.att.yahoo.com SSL 465
POP3 Server (Incoming Messages) pop.att.yahoo.com SSL 995

 

NTL @ntlworld.com

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.ntlworld.com SSL 465
POP3 Server (Incoming Messages) pop.ntlworld.com SSL 995

 

BT Connect

Server: Authentication: Port:
SMTP Server (Outgoing Messages) pop3.btconnect.com   25
POP3 Server (Incoming Messages) mail.btconnect.com   110

 

BT Openworld

Server: Authentication: Port:
SMTP Server (Outgoing Messages) mail.btopenworld.com   25
POP3 Server (Incoming Messages) mail.btopenworld.com   110

 

BT Internet

Server: Authentication: Port:
SMTP Server (Outgoing Messages) mail.btinternet.com   25
POP3 Server (Incoming Messages) mail.btinternet.com   110

 

Orange

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.orange.net   25
POP3 Server (Incoming Messages) pop.orange.net   110

 

Orange.uk

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.orange.co.uk   25
POP3 Server (Incoming Messages) pop.orange.co.uk   110

 

Wanadoo UK

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.wanadoo.co.uk   25
POP3 Server (Incoming Messages) pop.wanadoo.co.uk   110

 

Hotmail

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.live.com SSL 465
POP3 Server (Incoming Messages) pop3.live.com SSL 995

 

O2 Online Deutschland

Server: Authentication: Port:
SMTP Server (Outgoing Messages) mail.o2online.de   25
POP3 Server (Incoming Messages) pop.o2online.de   110

 

T-Online Deutschland

Server: Authentication: Port:
SMTP Server (Outgoing Messages) securesmtp.t-online.de StartTLS 587
POP3 Server (Incoming Messages) securepop.t-online.de SSL 995

 

1&1 (1and1)

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.1and1.com StartTLS 587
POP3 Server (Incoming Messages) pop.1and1.com SSL 995

 

1&1 Deutschland

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.1und1.de StartTLS 587
POP3 Server (Incoming Messages) pop.1und1.de SSL 995

 

Comcast

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.comcast.net   587
POP3 Server (Incoming Messages) mail.comcast.net   110

 

Verizon

Server: Authentication: Port:
SMTP Server (Outgoing Messages) outgoing.verizon.net SSL 465
POP3 Server (Incoming Messages) incoming.verizon.net SSL 995

 

Verizon (Yahoo hosted)

Server: Authentication: Port:
SMTP Server (Outgoing Messages) outgoing.yahoo.verizon.net   587
POP3 Server (Incoming Messages) incoming.yahoo.verizon.net   110

 

zoho Mail

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.zoho.com SSL 465
IMAP Server (Incoming Messages) pop.zoho.com SSL 995

 

Mail.com

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.mail.com SSL 465
IMAP Server (Incoming Messages) pop.mail.com SSL 995

 

 

+ Add Provider

Server: Authentication: Port:
SMTP Server (Outgoing Messages) Contact us to add your provider    
POP3 Server (Incoming Messages)      

 

This list is without any warranties!

A List of SMTP and IMAP Servers (Mail Server)

Default Ports:

Server: Authentication: Port:
SMTP Server (Outgoing Messages) Non-Encrypted AUTH 25 (or 587)
  Secure (TLS) StartTLS 587
  Secure (SSL) SSL 465
IMAP Server (Incoming Messages) Non-Encrypted AUTH 143
  Secure (TLS) StartTLS 143
  Secure (SSL) SSL 993

 

Googlemail - Gmail

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.gmail.com SSL 465
  smtp.gmail.com StartTLS 587
IMAP Server (Incoming Messages) imap.gmail.com SSL 993
  Please make sure, that IMAP access is enabled in the account settings.
Login to your account and enable IMAP.

 

Outlook.com

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp-mail.outlook.com StartTLS 587
IMAP Server (Incoming Messages) imap-mail.outlook.com SSL 993

 

Yahoo Mail

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.mail.yahoo.com SSL 465
IMAP Server (Incoming Messages) imap.mail.yahoo.com SSL 993

 

Yahoo Mail Plus

Server: Authentication: Port:
SMTP Server (Outgoing Messages) plus.smtp.mail.yahoo.com SSL 465
IMAP Server (Incoming Messages) plus.imap.mail.yahoo.com SSL 993

 

Yahoo Mail UK

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.mail.yahoo.co.uk SSL 465
IMAP Server (Incoming Messages) imap.mail.yahoo.co.uk SSL 993

 

Yahoo Mail Deutschland

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.mail.yahoo.com SSL 465
IMAP Server (Incoming Messages) imap.mail.yahoo.com SSL 993

 

Yahoo Mail AU/NZ

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.mail.yahoo.au SSL 465
IMAP Server (Incoming Messages) imap.mail.yahoo.au SSL 993

 

AT&T

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.att.yahoo.com SSL 465
IMAP Server (Incoming Messages) imap.att.yahoo.com SSL 993

 

NTL @ntlworld.com

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.ntlworld.com SSL 465
IMAP Server (Incoming Messages) imap.ntlworld.com SSL 993

 

BT Connect

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.btconnect.com   25
IMAP Server (Incoming Messages) imap4.btconnect.com   143

 

O2 Deutschland

Server: Authentication: Port:
SMTP Server (Outgoing Messages) mail.o2online.de   25
IMAP Server (Incoming Messages) imap.o2online.de   143

 

T-Online Deutschland

Server: Authentication: Port:
SMTP Server (Outgoing Messages) securesmtp.t-online.de StartTLS 587
IMAP Server (Incoming Messages) secureimap.t-online.de SSL 993

 

1&1 (1and1)

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.1and1.com StartTLS 587
IMAP Server (Incoming Messages) imap.1and1.com SSL 993

 

1&1 Deutschland

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.1und1.de StartTLS 587
IMAP Server (Incoming Messages) imap.1und1.de SSL 993

 

Verizon

Server: Authentication: Port:
SMTP Server (Outgoing Messages) outgoing.verizon.net   587
IMAP Server (Incoming Messages) incoming.verizon.net   143

 

zoho Mail

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.zoho.com SSL 465
IMAP Server (Incoming Messages) imap.zoho.com SSL 993

 

Mail.com

Server: Authentication: Port:
SMTP Server (Outgoing Messages) smtp.mail.com SSL 465
IMAP Server (Incoming Messages) imap.mail.com SSL 993

 

 

+ Add Provider

Server: Authentication: Port:
SMTP Server (Outgoing Messages) Contact us to add your provider    
IMAP Server (Incoming Messages)      

OOPS .Net Interview Questions

1. What is mean by Class?

Class is a structure that describes the state (property) and behavior (methods) of the object. It is a template or blueprint to create objects of the class. Class represents the noun and it can be used as type in programming language. E.g Car, Person etc

2. What is mean by Objects?

Object is an executable copy of a class. State and behavior of the objects are defined by class definition. We can create multiple objects for single class. It is also called as instance of the class. When an object is created from the class, memory will be allocated in RAM. e.g Car- Maruthi, Alto, Zen etc. Person- Ram, Sam, John etc

3. What is mean by Struture?

Structure is a light-weight class used to create user-defined types containing only public fields. Structure can't have implementation inheritance, but it can have interface inheritance. We cannot modify the default constructors as like a class. Structure is a value type holds their value in memory when they are declared.

4. What is difference between Class and Object?

Classes are the template or blueprint its state of how objects should be and behave, where as Object is an actual real term object. E.g CAR define state like it should have four wheel and body structure with moving, accelerating and break functionality. Maruthi, Alto or Zen is the real object which has different kind of state from one another.

5. What is difference between Class and Structure?
  • Class is Reference type(Reference types hold a reference to an object in memory) - Structure is a Value type(Value types hold their value in memory when they are declared)
  • User can modify default constructor and destructor of class- structure can't modify default constructor
  • Class supports inheritance - Structure will not support inheritance
  • Classes must be instantiated using the new operator - Structure can be instantiated without using the new operator
6. Which case we have to use Class and Structure?

Structure can be used for things that we no need for identity. Class can be used when we need the identity for an object.

7. What is the advantage of Structure over Class?

Since Stucture is a value type and if we use at the proper location, it will improve the performance.

9. What are advantages of using private constructor, method, property?

Due to security reason, methods and properties are not exposed outside the class using Private access modifier. For implementing Singleton pattern we go for Private Constructor, so we will not able to create instance. Separate method is used to create and return the instance.

10. What is mean by Partial class?

It is new features in .Net 2.0; partial classes mean that class definition can be split into multiple physical files. Logically, partial classes do not make any difference to the compiler. The compiler intelligently combines the definitions together into a single class at compile-time.

Example for Partial Class

partial class Employee
{
string m_Name;
public String Name
{
get { return m_Name; }
set { m_Name = value; }
}
}

partial class Employee
{
int m_Age;
public int Age
{
get { return m_Age; }
set { m_Age = value; }
}
}

public class ExampleofPartical
{
public void Method1()
{
Employee objClass1 = new Employee();
objClass1.Name="Name";
objClass1.Age = 12;
}
}

 


8. What are different access modifiers in .Net?


  • Private - The type or member can only be accessed by code in the same class or struct.
  • Protected - The type or member can only be accessed by code in the same class or struct, or in a derived class.
  • Internal - The type or member can be accessed by any code in the same assembly, but not from another assembly.
  • Procted Internal - The type or member can be accessed by any code in the same assembly, or by any derived class in another assembly.
  • Public -The type or member can be accessed by any other code in the same assembly or another assembly that references it.

Note: In VB.Net 'Internal' is called as 'Friend'

11. What is mean by Partial method?

Partial methods are methods defined in a partial class that are (optionally) divided across two files. With partial methods one file contains the method signature - the method name, its return type, and its input parameters - while the body is (optionally) defined in a separate file. If the partial method's body is not defined then the compiler automatically removes the partial method signature and all calls to the method at compile-time.

Example for Partial method

   {
string m_Name;
public String Name
{
get { return m_Name; }
set { m_Name = value; }
}
public partial string GetEmpDetails(string ID);

}

partial class Employee
{
int m_Age;
public int Age
{
get { return m_Age; }
set { m_Age = value; }
}
public partial string GetEmpDetails(string ID)
{
return "Employee1";
}
}

12. Why do we go for Partial method?

Partial methods are mainly useful in auto-generated code situations. A code generating tool might know that there are certain extension points that some users are going to be interested in customizing. For example, the objects created in LINQ to SQL have partial methods like OnLoaded, OnCreated, OnPropertyNameChanging, and OnPropertyNameChanged. The auto-generated code calls the OnCreated partial method from its constructor. If you want to run custom code when one of these objects is created you can create a partial class and define the body for the OnCreated partial method.

13. Why do we go for Partial class?


  1. Improve the readability of extremely large classes by partitioning related methods into separate files.
  2. Partial classes enable the code generator to generate code in one file while the developer who may need to extend the auto-generated logic can do so in a separate file, which eliminates the worry that the code generator might overwrite a developer's customizations.

14. Where we use Partial method and class?

Partial classes and partial methods are most commonly used in auto-generated code. It provides a simple and safe way to add new functionality or extend existing functionality of auto-generated code.

15. What are restrictions for Partial method?


  1. Partial definitions must preceded with the key word "Partial"
  2. Method signature should be same in both partial class file
  3. We cannot have partial implementation in one file and another implementation in other file. We can have declaration in one file and implementation in another file.

16. What is mean by Static class?

Static class is used to create attributes and methods that can be accessed without creating the instance of the class. Static classes are loaded automatically by the .NET Framework when application or assembly is loaded. 'Static' key word is used to mention the static class. e.g MyStaticClass.PI

Example for Static Class

public static class MyStaticClass
{
public static decimal PI = 3.14M;
public static int Add(int num1, int num2)
{
return num1 + num2;
}
public static string Append(string str1, string str2)
{
return str1 + str2;
}
}
MyStaticClass.PI


17. What is mean by Static method?

Static method can be accessed without creating the instance of the class. 'Static' key word is used to mention the static method. Static methods can be created inside the normal class or static class. If we create the static method inside the normal class, static method will not be able to access by creating instance of the class. e.g Math.Add()

18. Can we override static method?

No, compiler will not allow overriding the static method.

19. What are uses of static class and method?


  1. Compiler will not allow creating the instance of the class
  2. Static class also makes the implementation simpler and faster
  3. Cannot inherit a static class since it is sealed

20. What is static constructor?

A static constructor is used to initialize any static data, or to perform a particular action that needs performed once only. It is called automatically before the first instance is created or any static members are referenced.

Example:

public class MyStaticClass
{
static int count;

static MyStaticClass()
{
count = 0;
Console.WriteLine("Static class is initialized");
}

public static void MyMethod(string name)
{
Console.WriteLine("Static class is initialized " + name);
}
}

MyStaticClass.MyMethod("John");

Output:

Static class is initialized
Hello John

21. What are shared (VB.NET)/Static(C#) variables?

Static members are not associated with a particular instance of any class, which can be invoked directly from the class level, rather than from its instance

Example

public static double  PI = 3.1457;

22. What is Nested Classes?

Classes with in classes are called as Nested class.

Example

public class MyClassLevel_1
{
public void Display()
{
Console.WriteLine("Level_1");
}
public class MyClassLevel_2
{
public void Display()
{
Console.WriteLine("Level_2");
}

public class MyClassLevel_3
{
public void Display()
{
Console.WriteLine("Level_3");
}
}
}
}

Creating instance of the nested class

MyClassLevel_1 L1 = new MyClassLevel_1();
MyClassLevel_1.MyClassLevel_2 L2 = new MyClassLevel_1.MyClassLevel_2();
MyClassLevel_1.MyClassLevel_2.MyClassLevel_3 L3 = new
MyClassLevel_1.MyClassLevel_2.MyClassLevel_3();
L1.Display();
L2.Display();
L3.Display();

Output
Level_1
Level_2
Level_3


23. What are difference between Singleton and Static class?


  1. Singleton can extend classes and implement interfaces, while a static class cannot implement the interface.
  2. Singleton can be initialized lazily or asynchronously while a static class is generally initialized when it is first loaded.
  3. Singleton class can be extended and it's methods can be overridden.

24. Why Main () method is static?

To ensure there is only one entry point to the application.

25. What is mean by inheritance?

Inheritance is one of the concepts of object-oriented programming, where a new class is created from an existing class. Inheritance class is often referred to as subclasses, comes from the fact that the subclass (the newly created class) contains the attributes and methods of the parent class. This can be used to create a highly specialized hierarchical class structure.

Example of Inheritance

class Circle
{
private double m_radius;

public double Radius
{
get { return m_radius; }
set { m_radius = value; }
}
public double Diameter
{
get { return Radius * 2; }
}
public double Circumference
{
get { return Diameter * 3.14; }
}
public double Area
{
get { return Radius * Radius * 3.14; }
}
}

class Sphere : Circle
{
new public double Area
{
get { return 4 * Radius * Radius * 3.14; }
}

public double Volume
{
get { return 4 * 3.14 * Radius * Radius * Radius / 3; }
}
}


26. Can we inherit multiple classes?

No, multiple inheritances are not supported in .Net. Because consider the provided example. Here there are two Parent class Paretn1 and Parent2. This is inherited by Child class, In GetData method, child call the parent class method PrintData(). In this case which method will be executed? It is very difficult for CLR to identify which method to call. It shows that we multiple inheritance create ambiguity to oops concept. In order to avoid this ambiguity we are going for multiple interface implementations.

public class Parent1
{
public string PrintData()
{
return "This is parent1";
}
}
public class Parent2
{
public string PrintData()
{
return "This is parent2";
}
}

public class Child1 : Parent1, Parent2
{
public string GetData()
{
return this.PrintData();
}
}

27. What is mean by Shadowing?

When the method is defined in base class are not override able and we need to provide different implementation for the same in derived class. In this kind of scenario we can use hide the base class implementation and provide new implementation using Shadows (VB.Net)/new(C#) keyword.

Example:

Public Class ParentClass
Public Sub Display()
Console.WriteLine("Parent class")
End Sub

End Class

Public Class ChildClass
Inherits ParentClass

Public Shadows Sub Display()
Console.WriteLine("Child class")
End Sub
End Class


Dim p As New ParentClass
Dim c As New ChildClass
Dim pc As ParentClass = New ChildClass
p.Display()
c.Display()
pc.Display()

Output:
Parent class
Child class
Parent class


28. How a base class method is hidden?

Using new keyword in the derived class, base class method can be hidden or suppressed. New implementation can be added to the derived class.

29. What does the keyword virtual mean in the method definition?

The method can be over-ridden.

30. How method overriding different from overloading?

If we are overriding the method, derived class method behavior is changed from the base class. In Overloading, method with same name by different signature is used.

Example:

{
public virtual void Display()
{
Console.WriteLine("ParentClass");
}
}

public class ChildClass : ParentClass
{
//Example for method override
public override void Display()
{
Console.WriteLine("ChildClass");
}

//Example for method overload
public void Display(string name)
{
Console.WriteLine(name);
}
//Example for method overload
public void Display(string name, string country)
{
Console.WriteLine("Name:"+name +"Country: "+ country );
}
}


ParentClass p = new ParentClass();
ChildClass c = new ChildClass();
ParentClass pc = new ChildClass();
p.Display();
c.Display();
pc.Display();
 
OutPut:
ParentClass
ChildClass
ChildClass


31. Can you declare the override method static while the original method is non-static?

No

32. What is mean by Sealed Class?

Class which cannot be inherited is called as sealed class. If we need to prevent a class from being inherited, use “Sealed” keyword. But sealed class can inherited from other classes.

Example:

public class MyBaseClass
{
public void Display()
{
Console.WriteLine("Base class");
}
}

//Compile Success: This class cannot be inherited
public sealed class MySealedClass:MyBaseClass
{
public void Display()
{
base.Display();
Console.WriteLine("Sealed class");
}
}

//Compilation Error: cannot derive from sealed type MySealedClass
public class MyChildClass : MySealedClass
{

}

33. Can you allow class to be inherited, but prevent the method from being over-ridden?

Yes, just leave the class public and make the method sealed.

34. Will sealed class allows inheritance, if not why?

Sealed means it is not inheritable

35. What are the advantages of Private constructor?


  1. Private constructor will prevent the user from creating the instance of the class which contains only static members.
  2. Private constructor are used for implementing the singleton pattern

36. While using inheritance, derived class construct will call base class constructor?

Yes, base class constructor will be called before child class constructor

37. Overloaded constructor will call default constructor internally?

No, overload constructor will not call default constructor

38. What is difference between Overrides and Overridable?

Overridable (VB.Net)/ virtual (C#) is used in parent class to indicate that a method can be overridden. Overrides(VB.Net)/ override(C#) is used in the child class to indicate that you are overriding a method.

39. What is Method overloading?

Method overloading occurs when a class contains two methods with the same name, but different signatures.

40. What is operator overloading?

Operator overloading is used to provide a custom functionality to existing operators. For Example +,-,* and / operators are used for mathematical functionality. But we can overload these operators to perform custom operation on classes or structure.

Example:

To concatenate the two strings we have to use Concat method

Dim str1, str2, str3 As String
str1 = "Hello"
str2 = "world"
str3 = String.Concat(str1, str2)

But .Net provides in build operator overloading for string we can use ‘+’ operator for concatenating the string value

str3=str1+str2

Similarly we can also implement operator overloading for classes or structure

Employee3= Employee1 + Employee2

41. What is mean by abstraction?

Abstraction is the process of showing necessary information and hiding unwanted information. Let us consider the "CalculateSalary" in your Employee class, which takes EmployeeId as parameter and returns the salary of the employee for the current month as an integer value. Now if someone wants to use that method. He does not need to care about how Employee object calculates the salary? An only thing he needs to be concern is name of the method, its input parameters and format of resulting member

42. What is mean by abstraction class?

Abstract classes contain one or more abstract methods that do not have implementation. An abstract class is a parent class that allows inheritance but can never be instantiated. Abstract classes allow specialization of inherited classes.

43. What id mean by Interface?

Interface defines the set of properties, signature of the methods and events. It does not include any implementation. Class which implements the interface can provide the behavior to the implemented method. For example two class MyEnglishClassand MyFreanchClass implementing same interface and provide two different set of behavior in their implementation.

public interface IMyInterface
{
string Hello(string name);
}

public class MyEnglishClass:IMyInterface
{
public string Hello(string name)
{
return "Hello " + name;
}
}

public class MyFrenchClass : IMyInterface
{
public String Hello(string name)
{
return "allo " + name;
}
}


44. What is difference between Abstract class and Interface?


  • In Interface all the method must be abstract; in abstract class we can have both abstract and concrete methods.
  • Access modifiers cannot be specified in interface because it should always be public; in Abstract class, we can specify the access modifier.

45. In which Scenario you will go for Abstract or Interface Class?

Abstract classes are useful when creating components because they allow you specify an invariant level of functionality in some methods, but leave the implementation of other methods until a specific implementation of that class is needed. They also version well, because if additional functionality is needed in derived classes, it can be added to the base class without breaking code.

Interfaces are often used to describe the peripheral abilities of a class, not its central identity, e.g. an Automobile class might implement the Recyclable interface, which could apply to many otherwise totally unrelated objects.

46. What is mean by polymorphism?

Polymorphism means the ability to take more than one form. An operation may exhibit different behaviors in different instances. The behavior depends on the data types used in the operation. Polymorphism is extensively used in implementing Inheritance.

47. What are different types of polymorphism?

There are two types of polymorphism

Static polymorphism - defining the method with same name and different signature is called as static polymorphism. In the below example there are three different Add() functionality this Add() will be executed based on the parameter passed.

Example :

public int Add(int a, int b)
{
return a + b;
}

public double Add(double a, double b)
{
return a + b;
}

public long Add(long a, long b)
{
return a + b;
}


Dynamic polymorphism – Dynamic polymorphism can be implemented using Virtual and Override keyword. By using polymorphism, each derived class can have its own behavior, Even though classes are derived or inherited from the same parent class

Example:

In the below example ClassB is inherited from ClassA. ClassB can have its own behavior by overriding the parent class method. Parent class method should be represented with virtual keyword to override the same method in derived class.

public class ClassA
{
public virtual void Display()
{
Console.WriteLine ( "ClassA");
}
}

public class ClassB:ClassA
{
public override void Display()
{
Console.WriteLine ( "ClassB");
}
}

static void Main(string[] args)
{
ClassA a = new ClassA();
ClassB b = new ClassB();
ClassA c = new ClassB();
a.Display();
b.Display();
c.Display();
Console.ReadLine();

}

OutPut:
ClassA
ClassB
ClassB



48. What you mean by Encapsulation?

Encapsulation is the procedure of covering up of data and functions into a single unit and protects the data from the outside world. Example “Class” only public functions and properties are exposed; functions implementation and private variables are hidden from outside world.

49. What is difference between data encapsulation and abstraction?

Abstraction refers to the act of representing essential features without including the background details or explanations. Storing data and functions in a single unit is called as encapsulation.

50. What is mean by Delegate?

Delegate is a type that holds a reference to a method or a function. . Once a delegate is assigned a method, it behaves exactly like that method. We can call the method using delegate instead of directly calling the method. Using delegate, we can also pass the parameter and get return value. Any method with matched the signature of the delegate can be assigned. Simply we can say .NET implements the concept of function pointers using delegate.

Example:

There are three step to following for using Delegate


  • Declaration
  • Instantiation
  • Invocation

In the below example we have declared the new delegate “MyDelegate”, which accept string as parameter and return value as string. Two methods SayHello and SayBye function will be called using delegate.

//Declaring the delegate
delegate string MyDelegate(string name);

//function called by delegate dynamically
private static string SayHello(string name)
{
return "Hello " + name;
}

private static string SayBye(string name)
{
return "Bye " + name;
}


After declaration of delegate, we have initialized with SayHello function. Now this delegate will hold reference to specified function. Function will be called using Invoke () method of delegate. In this example we have called two methods (SayHello and SayBye) with same signature(parameter type and return type).

static void Main(string[] args)
{

//Initialllizing delegate with function name
MyDelegate delg = new MyDelegate(SayHello);
//Invoking function using delegate
Console.WriteLine(delg.Invoke("Sam"));

delg = new MyDelegate(SayBye);
//Invoking diffent function using same delegate
Console.WriteLine(delg.Invoke("Sam"));

Console.ReadLine();
}

OutPut:
Hello Sam
Bye Sam


51. What’s a multicast delegate?

It’s a delegate that stores the address of multiple methods and eventually fires off several methods. Multicast delegate must have a return type of void.

52. What is an Asynchronous delegate?

When you invoke a delegate asynchronously, no new thread is created. Instead, the CLR automatically assigns a free thread from a small thread pool that it maintains. Typically, this thread pool starts with one thread and increases to a maximum of about 25 free threads on a single-CPU computer. As a result, if you start 50 asynchronous operations, one after the other, the first 25 will complete first. As soon as one ends, the freed thread is used to execute the next asynchronous operation.

53. What is mean by Events?

Events are nothing but a publisher and subscriber model. Any subscriber who is interested in receiving notification from the publisher can subscribe the events. If source event is fired or publisher raises the event, a notification will be send to all subscribers. One publisher can have multiple subscribers. Internally events will try to make use of delegate for this publisher, subscription model.

Example:

In the below example, we have created new event called "SampleEvent" and this event will be fired once MyMethod() is called. Anyone who wants to subscribe to this event can create a instance of the MyClassWithEvent and add handler to the event. So when ever event is raised, add handler method will be called.

Public Class MyClassWithEvent

'Created New Event, which will return a message to all subscriber
Event SampleEvent(ByVal message As String)

'Event will be fired once this method is called
Public Sub MyMethod()
Console.WriteLine("MyMethod is called")
'Raising the event with message
RaiseEvent SampleEvent("Event is Raised from MyClassWithEvent")
End Sub
End Class

Module Module1

Sub Main()

Dim c As New MyClassWithEvent
'First subscriber of the event
AddHandler c.SampleEvent, AddressOf EventSubscriber1
'Second subscriber of the event
AddHandler c.SampleEvent, AddressOf EventSubscriber2
c.MyMethod()
Console.ReadLine()
End Sub

Private Sub EventSubscriber1(ByVal message As String)
Console.WriteLine("Subscriber 1")
Console.WriteLine("Message: " + message)
End Sub

Private Sub EventSubscriber2(ByVal message As String)
Console.WriteLine("Subscriber 2")
Console.WriteLine("Message: " + message)
End Sub
End Module

OutPut:
MyMethod is called
Subscriber 1
Message: Event is Raised from MyClassWithEvent
Subscriber 2
Message: Event is Raised from MyClassWithEvent


54. Can event’s have access modifiers?

Yes, Event’s can have access modifier, if we mention it as Protected events can be subscribed only within inherited class, If you mention it as Internal(C#)/Friends(VB.Net) it can be subscribed by all class inside the assembly. If you mention it as Private it can subscribed with in class where it is declared.

55. Can we have static/shared events?

Yes, we can have static(C#)/shared(VB.Net) event, but only shared method can raise shared events.

56. Can we have different access modifier for Get/Set of the properties?

Yes, in C# 3.0 and above, we can use different access modifier for Get/Set of the properties, but this is not possible in C#2.0 and lower

57. What is an indexer?

An indexer is an accessor that enables an object to be treated in the same way as an array. An indexer is considered when a class is better represented as a virtual container of data that can be retrieved or set using indices. Since an indexer is nameless, its signature is specified by the keyword “this” followed by its indexing parameters within square brackets.

Example:

In the below example we have created new index for class of type string. During get and set operation string manipulations are done.

public class MyClassForIndexer
{
private string m_Name = "This is example for indexer";
public string this[int index]
{
get
{
return m_Name.Substring( index);
}
set
{
m_Name = m_Name.Insert(index, value);
}
}
}
MyClassForIndexer ind = new MyClassForIndexer();
Console.WriteLine (ind[0]);
ind[7] = "Appended String";
Console.WriteLine(ind[0]);
Output:
This is example for indexer
This isAppended String example for indexer


58. What is ENUM?

ENUM means Enumeration; it is used to group related sets of constants. To create a enumeration you use the Enum statement

Example:

Enum Months
January = 1
Feburary = 2
March = 3
April = 4
May = 5
June = 6
July = 7
August = 8
September = 9
October = 10
November = 11
December = 12
End Enum


LINQ Interview Questions

1. What is mean by LINQ?

LINQ stands for Language Integrated Query. It is a uniform platform for any kind data. It allows us to write a query against Object Collection, Database, XML or other Data source in a standard form without having a separate Query Language.

2. How LINQ works?

Consider the sample customer class with two public members Name and City.

public class Customer
{
public string Name;
public string City;
}


In a console application, customer list with different Name and city are added. Using LINQ retrieve all the customers located in "Coimbatore" city and displays the name of the customer.

//Added a list of customers to the Customers collection list
List Customers = new List(){
new Customer(){Name="Sam",City="Coimbatore"}
,new Customer(){Name="Ram",City="Chennai"}
,new Customer(){Name="Sasi",City="Coimbatore"}};
//Using LINQ to retrive all the customers located in Coimbatore city
var query = from c in Customers
where c.City == "Coimbatore"
select c;
//Displaying all the customer located in Coimbatore city
foreach (Customer c in query)
{
Console.WriteLine(c.Name);

}
Console.ReadLine();
}



The compiler generates the following query for the LINQ

IEnumerable query = Customers.Where(c => c.City == "Coimbatore");

In this compiler generated code, "Where" is a extension method features introduced in C# 3.0 to filter the data based on condition. LINQ make use of these features to query data from object collection. Similar to the Where, we have Select, OrderBy, etc extension methods supported for object collection.

This query will be executed to retrieve data from the collection

3. How will you work with relative model using LINQ?

Using "Join" keyword we can describe relation between two entities as like SQL join statement. E.g In the below query we are joining the Customer collection with Orders collection using CustomerID members. End result we are returning new anonymous type with CustomerID, customer name, orderID as member.

var query = from c in Customers
join o in Orders
on c.CustomerID equals o.Customer.CustomerID
select new { c.CustomerID, c.Name, o.OrderID };


4. In given line of LINQ, when actual query will be executed and why?

In general, a LINQ query is not really executed until there is access the query result, because it describes set of operations that will be performed when necessary. In the below example actual query is executed only in the foreach loop

//Added a list of customers to the Customers collection list
List Customers = new List(){
new Customer(){Name="Sam",City="Coimbatore"}
,new Customer(){Name="Ram",City="Chennai"}
,new Customer(){Name="Sasi",City="Coimbatore"}};
//Using LINQ to retrive all the customers located in Coimbatore city
var query = from c in Customers
where c.City == "Coimbatore"
select c;
//Displaying all the customer located in Coimbatore city
foreach (Customer c in query)
{
Console.WriteLine(c.Name);

}


5. What is mean by declarative programming?

Declarative programming is a programming paradigm that expresses the logic of a computation without describing its control flow. There is main difference between filtering data using SQL query and C# (2.0) language such as table for SQL or an array for C# or VB.net. SQL describes what you want, where as in C# describe how to obtain the expected result. In SQL the selection of the best algorithm to implement the "How" is the responsibility of the query engine. It shows that SQL query engine has more freedom to apply optimization than c#.

6. Is LINQ is Type safe or not?

Data used in the LINQ area always strongly typed, including both the queried collections and the singe entities that are read and returned.

7. What is the use of "Yield" type?

Yeild key word is used to iterate through objects returned by a method. Method with IEnumerable return type can be used with Yeild type.

Example:

public static IEnumerable Power(int num, int exponent)
{
int counter = 1;
int result = 1;
//Loop till the power count reach exponent value
while (counter < exponent)
{
result = result * num;
counter++;
//Returns power of num at each level e.g num, num^2, num^3....
yield return result;
}
}


8. How will you map class with database table in LINQ? Or How will you create Entity class in LINQ?

Class and Database table can be mapped using Table and Column attribute. Table Attribute has Name property to specify the name of the database table. If Name property is not supplied then LINQ-> SQL will assume database table has the same name as the class.Column attribute has few properties which is used to customize the exact mapping between entity and database.

[Table(Name = "Customers")]
public class Customer
{
[Column(IsPrimaryKey = true)]
public string CustomerID;
[Column]
public string Name;
[Column]
public string City;
}


9. Why "from" clause is stated before "select" clause in LINQ which is not available in SQL?

In LINQ, all the query starts with a "from" clause and ends with "Select" clause because Microsoft want to provide IntelliSense capabilities within the remaining part of the query which make writing rest part of the query easier.

10. What is difference between LINQ->SQL and LINQ->Entity?


  • Linq-to-SQL is for direct queries using SQL Server. It's a mapping technology to map SQL Server database tables to .NET objects.
  • Linq-to-Entities is Linq used while using Microsoft's Entity Framework, regardless of db server

11. What are different operators used in LINQ?


  1. Where Operators - Where
  2. Projection Operators - Select, SelectMany
  3. Ordering Operators - OrderBy , OrderByDescending, ThenBy, ThenByDescending, Reverse
  4. Grouping Operators - Group By
  5. Join Operators - Join, GroupJoin
  6. Set Operators - Distinct, Union, Intersect, Except
  7. Aggregate Operators - count, LongCount, Sum,Min,Max, Avagrage, aggregate
  8. Generation Operators - Range, Repeat, Empty
  9. Qualifiers Operators -Any, All, Contains,
  10. Partitioning Operators -Take, TakeWhile, Skip, SkipWhile
  11. Element Operators - First, FirstOrDefault,Single, SingleOrDefault, ElementAt, ElementAtOrDefault, DefaultEmpty
  12. Other Operators - Concat, SequenceEqual

12. What are two main concepts in LINQ?

Two main concepts which is used to understand the LINQ are Deferred query evaluation and Extension method


  • Deferred Query Evaluation - LINQ queries are not evaluated when it is defined but when it is used. It is useful by defining once and used many times when it is required. Result of the query expression will always be based on latest updated content.
  • Extension Method - This allows developer to add functionality in existing class without modifying the existing class or recompiling the existing class or extending the existing class. LINQ make use of this extension method for manipulating data e.g Where, Select...etc

13. What is mean by DLINQ?

DLINQ stands for Data Language Integrated Query, it is also referred to as LINQ to SQL. It is specifically the version of LINQ that focuses on querying data from relational data sources. In Dlinq, DataContext is the main object through which we will be retrieve objects from the database and submit changes back to DB.

14. How SQL query generated from Linq query?

In LINQ, DataContext class is used to communicate between LINQ and SQL. It accept and IConnection class to establish connection with SQL. It uses metadata information to map the Entity with physical structure of database.

[Table(Name = "Customers")]
public class Customer
{
[Column(IsPrimaryKey = true)]
public string CustomerID;
[Column]
public string Name;
[Column]
public string City;
}


15. How will you read data from SQL using Dlinq?

Using DLINQ user can easily read the data from SQL. Visual studio provides inbuilt template to create link between LINQ and SQL.

Example:


  • Create a sample console application and add new item to the project
  • In the shown template select "LINQ to SQL Classes". A new dbml file will be added to your project.
  • Connect to the SQL server using Server Explorer and drag and drop any folder that we need to read the data.
  • This ".dbml" file create a "Employee" Entity mapping to database table. Database column will be mapped to property of the Employee class.


  • Once Table are mapped to Entity, automatically connection string will be added to your application as shown below.

    <connectionStrings>

    <add name="AdventureWorksConnectionString"

    connectionString="Data Source=SARAVANAK-6930\SQLEXPRESS;



    • Initial Catalog=AdventureWorks;Integrated Security=True"


    providerName="System.Data.SqlClient" />

    </connectionStrings>


  • As we discuss DataContext instance is root, through which we can access the corresponding table in database. In the below example I try to read the Employee table with employeeId 1 to 10.
    //Creating connection string for DataContext object
    SqlConnection conn = new SqlConnection();
    string connString = System.Configuration.ConfigurationManager
    .ConnectionStrings["AdventureWorksConnectionString"].ToString();
    conn.ConnectionString = connString;
    //Get the object of the Datacontext
    AdventureWorksDBDataContext adWorksDC = new AdventureWorksDBDataContext(conn);

    //Query from table
    //Read the employee with ID between 1 and 10
    var employees = from emp in adWorksDC.Employees
    where emp.EmployeeID >=1 && emp.EmployeeID<10
    select emp;

    foreach (Employee e in employees )
    {
    Console.WriteLine(String.Format("LoginName: {0}", e.LoginID) );
    }


    Output:


16. How will you Insert record to DB table using LINQ?

A new data record can be inserted to Database table using InsertOnSubmit() method available in DataContext instance. Developer should call the SubmitChanges() method to commit the database transaction else data will not be insert in database table.

Example:

Below sample code shows to insert new Product Category record to database using LINQ.

        //Inserting the Product category into table
ProductCategory cate = new ProductCategory();
cate.ProductCategoryID = 5;
cate.Name = "New Category";
cate.rowguid = System.Guid.NewGuid();
cate.ModifiedDate = DateTime.Now;
adWorksDC.ProductCategories.InsertOnSubmit (cate);
adWorksDC.SubmitChanges();



17. How to update data using linq?

Database update can be done using "SubmitChanges()" method in DataContext instance.

18. How will you call Store procedure using LINQ?

We can call the store procedure define in DB using "Function" and "Parameter" attribute. Consider the below example where user need to call the store procedure "uspGetEmployeeManagers" using LINQ->SQL, for which method "GetEmployeeManagers" will be decorated with Function attribute which requires "Name" property to mention to which SP need to call. If SP requires parameter value, these values can be passed using "Parameter" attribute. SP can return single or multiple result set. For Single result set we will be mapping with ISingleResult return type for multiple result set method it will return IMultipleResults return type of collection. Objects return by the SP will be mapped to new class with columns are mapped to property of the class.

SP mapped to Method

[System.Data.Linq.Mapping.Function(Name="dbo.uspGetEmployeeManagers")]
public ISingleResult GetEmployeeManagers([System.Data.Linq.Mapping.
Parameter(Name="EmployeeID", DbType="Int")] System.Nullable employeeID)
{
IExecuteResult result = this.ExecuteMethodCall(this,
((MethodInfo)(MethodInfo.GetCurrentMethod())), employeeID);
return ((ISingleResult)(result.ReturnValue));
}


Calling SP using method

////Creating connection string for DataContext object
SqlConnection conn = new SqlConnection();
string connString = System.Configuration.ConfigurationManager
.ConnectionStrings["AdventureWorksConnectionString"].ToString();
conn.ConnectionString = connString;
//Get the object of the Datacontext
AdventureWorksDBDataContext adWorksDC = new AdventureWorksDBDataContext(conn);

//Calling SP using method and iterating through values
foreach (uspGetEmployeeManagersResult e in adWorksDC.GetEmployeeManagers(1))
{
Console.WriteLine(String.Format("EmpID: {0} Name: {1}", e.EmployeeID, e.FirstName));
}
Console.ReadLine();


19. How will you call User Define Function using LINQ?

Similar to calling store procedure, functions also called using "Function" and "Parameter" attribute.

Please refer "How will you call Store procedure using LINQ?" for more information

Example:Function mapped to a method

[System.Data.Linq.Mapping.Function(Name="dbo.ufnGetContactInformation", IsComposable=true)]
public IQueryable GetContactInformation
([global::System.Data.Linq.Mapping.Parameter(Name="ContactID", DbType="Int")] System
.Nullable contactID)
{
return this.CreateMethodCallQuery(
this, ((MethodInfo)(MethodInfo.GetCurrentMethod())), contactID);
}


Calling function using LINQ

//Creating connection string for DataContext object
SqlConnection conn = new SqlConnection();
string connString = System.Configuration.ConfigurationManager
.ConnectionStrings["AdventureWorksConnectionString"].ToString();
conn.ConnectionString = connString;
//Get the object of the Datacontext
AdventureWorksDBDataContext adWorksDC = new AdventureWorksDBDataContext(conn);

//Calling Function by passing parameter as '1'
foreach (ufnGetContactInformationResult c in adWorksDC.GetContactInformation (1))
{
Console.WriteLine(String.Format("ContactID: {0} Name: {1}", c.ContactID , c.FirstName));
}


20. How to provide Ready only access to DB?

Suppose if we need to access data only in a read-only way and if we need to improve performance by disabling DataContext class to modify by using ObjectTrackingEnabled property of the Datacontext class

AdventureWorksDBDataContext adWorksDC = new AdventureWorksDBDataContext(conn);
adWorksDC.ObjectTrackingEnabled = false;


21. How will you enable transaction in LINQ->SQL?

A SubmitChanges() in DataContext call automatically starts a database explicit transaction. Using the TransactionScope class contained in the System.Transaction library will be transparently promoted to a distributed transaction.

Example:

    using (TransactionScope ts = new TransactionScope())
{
//Inserting the Product category into table
ProductCategory cate = new ProductCategory();
cate.ProductCategoryID = 5;
cate.Name = "New Category";
cate.rowguid = System.Guid.NewGuid();
cate.ModifiedDate = DateTime.Now;
adWorksDC.ProductCategories.InsertOnSubmit(cate);
adWorksDC.SubmitChanges();
ts.Complete();
}


22. How to create and delete DB from LINQ?

We can create database using DataContext class, if we have a class derived from DataContext that contains entity definition decorated with Table and Column attributes, we can create the corresponding batabase by calling the "CreateDatabase" method.

Example:

MyDatabaseContext myDBContext = new MyDatabaseContext("Data Source=SARAVANAK-6930;
Initial Catalog=MyNewDatabase;Integrated Security=True");
myDBContext.CreateDatabase();



23. What is the LINQ file extension that interacts with Code Behind's objects?

*.dbml

24. What are the error reporting options during concurrency conflicts?

There are two ways to report conflicts while summiting changes to database using linq.

ContinueOnConflict :- Specifies that all the update to the database to be tried and finally return all conflicts at the end of the process.

FailOnFirstConflict :- Specifies that attempts to update database should stop immediately when first concurrency conflicts are detected and return all the conflicts at that moment. In other words LINQ engine does not continue ahead executing the code.

Example:

adWorksDC.SubmitChanges(ConflictMode.FailOnFirstConflict);

25. What are advantages of LINQ over Store procedure?


  • Debugging SP is very difficult, where as LINQ is simple by using visual studio
  • Compile time safety when your schema changes
  • Deployment is easier in linq everything is compiled to dll, where as in DB we need to manage deployment script.

26. What are disadvantage of LINQ over Store procedure?


  • Store procedure can take full advantage of SQL features where as there will be some features missing in LINQ
  • Store process need only serialize SP name and argument data over the wire while LINQ sends the entire query.
  • Redeployment, if we need any modification, we need to recompile assembly in LINQ, where as in SP it is not the case.

27. What is XLINQ?

XLINQ = LINQ->XML, it is XML programming API to query XML data using LINQ. XLINQ provides power of both DOM and XQuery/XPath through LINQ extension methods to manage and query in-memory XML nodes.

28. How will you create xml document object using XLINQ?

XML Document can be created using XDocument, XDeclaration , XElement, XAttribute instance

Example:

XDocument xDocEmployee = new XDocument(
new XDeclaration("1.0", "utf-8", "yes"),
new XElement("Employee",
new XAttribute("ID", "2012"),
new XElement("FirstName", "Ram"),
new XElement("LastName", "Kumar"),
new XElement("Salary", 10000)));


XML document

<?xml version="1.0" encoding="utf-8" standalone="yes" ?>

<Employee ID="2012">

<FirstName>Ram</FirstName>

<LastName>Kumar</LastName>

<Salary>10000</Salary>

</Employee>

29. How will you read xml content using LINQ?

Consider the xml document with list of employee. Below example gives filtering and reading the employee details based on designation.

XML Document

<?xml version="1.0" encoding="utf-8" ?>

<Employees>

  <Employee ID="101">

    <FirstName>Ram</FirstName>

    <LastName>Kumar</LastName>

    <Designation>SE</Designation>

  </Employee>

  <Employee ID="102">

    <FirstName>Sasi</FirstName>

    <LastName>Kumar</LastName>

    <Designation>SSE</Designation>

  </Employee>

  <Employee ID="103">

    <FirstName>Praveen</FirstName>

    <LastName>prakash</LastName>

    <Designation>SSE</Designation>

  </Employee>

</Employees>

LINQ Query

var employees = 
from e in xDocEmployee.Elements("Employee")
where e.Element("Designation").Value == "SSE"
select new { Name = e.Element("FirstName").Value, ID = e.Attribute("ID").Value };


30. How can we do an order by using LINQ query?

Order by in LINQ is pretty simple. We just need to insert order by before the 'Select' query.

var employees = from emp in adWorksDC.Employees 
where emp.EmployeeID >=1 && emp.EmployeeID<10
orderby emp.EmployeeID
select emp;


31. What is the purpose of LINQ Providers in LINQ?

LINQ Providers are a set of classes that takes a LINQ query and dynamically generates a method that executes an equivalent query against a specific data source.

Retrive DynamicEntity from FetchXml query

Hi everyone , some times you need to supply a query form outside the code in a MS CRM solution. Using the following code snippet we can create the query dynamically and pass it to the code to get dynamic entities.

Now suppose i need to execute this query

<fetch mapping='logical'>
    <entity name='contact'>
        <filter type='and'>
            <condition attribute='lastname' operator='eq' value='xyz’/>
        </filter>
    </entity>
</fetch>

to get a list of dynamic entitles

Now either we can break the query and let the code just to have the logical section form this fetchXml or we can use the fetchXml as a whole. Now if i break the query  like

<entity name='contact'>
<filter type='and'>
<condition attribute='lastname' operator='eq' value='xyz’/>
</filter>
</entity>
And inside the code i can

		// here new_criteria contains the logical section from fetch xml(see above)
StringBuilder QueryBuilder = new StringBuilder(new_criteria);
QueryBuilder.Insert(0, "", 1);
QueryBuilder.Insert(QueryBuilder.Length, "
", 1);





Now the next thing i need to do is to convert his query to a CRM QueryExpression, thankfully CRM SDK contains some request & response classes to help






//This is the request/response object to Convert the FetchXML into a query expression.
FetchXmlToQueryExpressionRequest conversionRequest = new FetchXmlToQueryExpressionRequest
{
FetchXml = QueryBuilder.ToString()
};

// and here is the response
FetchXmlToQueryExpressionResponse conversionResponse =
(FetchXmlToQueryExpressionResponse)crmService.Execute(conversionRequest);




Now as we know that the query will results multiple records we will use it in RetriveMultiple


//Retrive Multiple Request
RetrieveMultipleRequest retrieve = new RetrieveMultipleRequest();
retrieve.Query = conversionResponse.Query;
retrieve.ReturnDynamicEntities = true;

//Retrieve Multiple Response
RetrieveMultipleResponse retrieved = (RetrieveMultipleResponse)crmService.Execute(retrieve);

if (retrieved.BusinessEntityCollection.BusinessEntities.Count > 0 )
{
for (int entityCount = 0; entityCount < retrieved.BusinessEntityCollection.BusinessEntities.Count; entityCount++)
{
// retrive the first entity form the collection
DynamicEntity entity = (DynamicEntity)retrieved.BusinessEntityCollection.BusinessEntities[entityCount];


}
}



Converting a JavaScript Date object into the proper XML string


function SwConvertDateTimeToXml(dateTime) {

var offset = (ORG_TIMEZONE_OFFSET < 0) ? -ORG_TIMEZONE_OFFSET : ORG_TIMEZONE_OFFSET;
var timezoneOffsetHours = Math.floor(offset / 60);
var timezoneOffsetMinutes = offset - timezoneOffsetHours * 60;

var s =
dateTime.getYear().toString() + "-" +
SwGetFormattedDatePart(dateTime.getMonth() + 1) + "-" +
SwGetFormattedDatePart(dateTime.getDate()) + "T" +
SwGetFormattedDatePart(dateTime.getHours()) + ":" +
SwGetFormattedDatePart(dateTime.getMinutes()) + ":" +
SwGetFormattedDatePart(dateTime.getSeconds()) +
((ORG_TIMEZONE_OFFSET < 0) ? "-" : "+") +
SwGetFormattedDatePart(timezoneOffsetHours) + ":" +
SwGetFormattedDatePart(timezoneOffsetMinutes);

return s;
}

function SwGetFormattedDatePart(value) {
return (value < 10) ? ("0" + value.toString()) : value.toString();
}

Converting an XML date string to a JavaScript Date object


function SwConvertXmlToDateTime(crmDateTimeString) {
var dateTimeParts = crmDateTimeString.split("T");
var dateString = dateTimeParts[0];
var timeString = dateTimeParts[1];
var dateParts = dateString.split("-");
var timeZoneSeparator = (timeString.indexOf("-") != -1) ? "-" : "+";
var timeZoneParts = timeString.split(timeZoneSeparator);
var timeParts = timeZoneParts[0].split(":");

var date = new Date(SwParseInt(dateParts[0]), SwParseInt(dateParts[1]) - 1, SwParseInt(dateParts[2]), SwParseInt(timeParts[0]), SwParseInt(timeParts[1]), SwParseInt(timeParts[2]));
return date;
}

function SwParseInt(value) {
if ((value.length == 2) && (value.substr(0, 1) == "0")) {
value = value.substr(1, 1);
}

return parseInt(value);
}

CrmService proxy for plug-ins that execute in the child pipeline.

We always come across creating a CrmService Proxy for plug-ins that execute in the child pipeline. In a Child pipeline, you must instantiate the CrmService or MetadataService manually. We just need to check the InvocationSource Property (Child = 1, Parent = 0) of the IPluginExecutionContext. Pass the InvocationSource Property value to the below method.

Below is very simple code which creates a proxy.




public class CRM4_ServiceProx
{


/// The execution context that was passed to the plug-in's Execute method.
/// Set to True to use impersonation.
/// A CrmServce instance.
private CrmService CreateCrmService(IPluginExecutionContext context, Boolean flag)
{
CrmAuthenticationToken authToken = new CrmAuthenticationToken();
authToken.AuthenticationType = 0;
authToken.OrganizationName = context.OrganizationName;

// Include support for impersonation.
if (flag)
authToken.CallerId = context.UserId;
else
authToken.CallerId = context.InitiatingUserId;

CrmService service = new CrmService();
service.CrmAuthenticationTokenValue = authToken;
service.UseDefaultCredentials = true;

// Include support for infinite loop detection.
CorrelationToken corToken = new CorrelationToken();
corToken.CorrelationId = context.CorrelationId;
corToken.CorrelationUpdatedTime = context.CorrelationUpdatedTime;
corToken.Depth = context.Depth;
//Get the server name form registry
RegistryKey regkey = Registry.LocalMachine.OpenSubKey("SOFTWARE\\Microsoft\\MSCRM");

service.Url = String.Concat(regkey.GetValue("ServerUrl").ToString(), "/2007/crmservice.asmx");
service.CorrelationTokenValue = corToken;

return service;
}

}


List of Webservices in Dynamics CRM 2011

Here is the list of services avaialable in CRM 2011. May sametimes you make use of some of it http:// crmserver:5555/AppWebServices/ActivitiesWebService.asmx http:// crmserver:5555/AppWebServices/AdvancedFind.asmx http:// crmserver:5555/AppWebServices/Annotation.asmx http:// crmserver:5555/AppWebServices/AppGridWebService.asmx http:// crmserver:5555/AppWebServices/AssociateRecords.asmx http:// crmserver:5555/AppWebServices/BulkDelete.asmx http:// crmserver:5555/AppWebServices/Connection.asmx http:// crmserver:5555/AppWebServices/Currency.asmx http:// crmserver:5555/AppWebServices/CustomerService.asmx http:// crmserver:5555/AppWebServices/DashboardWebService.asmx http:// crmserver:5555/AppWebServices/DateTimeService.asmx http:// crmserver:5555/AppWebServices/DialogList.asmx http:// crmserver:5555/AppWebServices/DocumentManagementWebService.asmx http:// crmserver:5555/AppWebServices/DuplicateDetection.asmx http:// crmserver:5555/AppWebServices/EmailTemplateService.asmx http:// crmserver:5555/AppWebServices/FormEditorWebService.asmx http:// crmserver:5555/AppWebServices/GanttControlWebService.asmx http:// crmserver:5555/AppWebServices/GoalManagement.asmx http:// crmserver:5555/AppWebServices/ImportJob.asmx http:// crmserver:5555/AppWebServices/ImportWebService.asmx http:// crmserver:5555/AppWebServices/InteractiveWorkflowWebService.asmx http:// crmserver:5555/AppWebServices/LookupMruWebService.asmx http:// crmserver:5555/AppWebServices/LookupService.asmx http:// crmserver:5555/AppWebServices/MailMerge.asmx http:// crmserver:5555/AppWebServices/MarketingAutomation.asmx http:// crmserver:5555/AppWebServices/MergeRecords.asmx http:// crmserver:5555/AppWebServices/MessageBar.asmx http:// crmserver:5555/AppWebServices/MruWebService.asmx http:// crmserver:5555/AppWebServices/OwnerManager.asmx http:// crmserver:5555/AppWebServices/PaneWebService.asmx http:// crmserver:5555/AppWebServices/PresenceService.asmx http:// crmserver:5555/AppWebServices/QueueItem.asmx http:// crmserver:5555/AppWebServices/RecentlyViewedWebService.asmx http:// crmserver:5555/AppWebServices/RegionalOptions.asmx http:// crmserver:5555/AppWebServices/RelatedInformation.asmx http:// crmserver:5555/AppWebServices/RelationshipRolePicklist.asmx http:// crmserver:5555/AppWebServices/reports.asmx http:// crmserver:5555/AppWebServices/ResourceGroupUI.asmx http:// crmserver:5555/AppWebServices/ResourceSpecTree.asmx http:// crmserver:5555/AppWebServices/Ribbon.asmx http:// crmserver:5555/AppWebServices/SalesForceAutomation.asmx http:// crmserver:5555/AppWebServices/SavedQuerySelectorWebService.asmx http:// crmserver:5555/AppWebServices/SchedulePlanning.asmx http:// crmserver:5555/AppWebServices/ScheduleService.asmx http:// crmserver:5555/AppWebServices/ScriptError.asmx http:// crmserver:5555/AppWebServices/Service.asmx http:// crmserver:5555/AppWebServices/Solution.asmx http:// crmserver:5555/AppWebServices/SubjectManager.asmx http:// crmserver:5555/AppWebServices/SystemCustomization.asmx http:// crmserver:5555/AppWebServices/TransactionCurrencyWebService.asmx http:// crmserver:5555/AppWebServices/UserEntityUISettings.asmx http:// crmserver:5555/AppWebServices/UserManager.asmx http:// crmserver:5555/AppWebServices/UserQuery.asmx http:// crmserver:5555/AppWebServices/View.asmx http:// crmserver:5555/AppWebServices/Workflow.asmx http:// crmserver:5555/MSCRMServices/Metadata.asmx http:// crmserver:5555/MSCRMServices/2007/CrmService.asmx http:// crmserver:5555/MSCRMServices/2007/MetadataService.asmx http:// crmserver:5555/MSCRMServices/2007/AD/CrmDiscoveryService.asmx

Passing Data Between Plug-ins [Microsoft Dynamics CRM 4.0]

The message pipeline model provides for a PropertyBag of custom data values in the execution context that is passed through the pipeline and shared among registered plug-ins. This collection of data can be used by different plug-ins to communicate information between plug-ins and enable chain processing where data processed by one plug-in can be processed by the next plug-in in the sequence and so on. This feature is especially useful in pricing engine scenarios where multiple pricing plug-ins pass data between one another to calculate the total price for a sales order or invoice. Another potential use for this feature is to communicate information between a plug-in registered for a pre-event and a plug-in registered for a post-event.

The name of the parameter that is used for passing information between plug-ins is SharedVariables. This is a collection of System.Object. A common type of object that is used to fill the collection is DynamicEntity. At run time, plug-ins can add, read, or modify properties in the SharedVariables property bag. This provides a method of information communication among plug-ins.

Note Only types that are XML serializable should be placed in SharedVariables. All types derived from BusinessEntity are XML serializable.

The following code example shows how to use SharedVariables to pass data from a pre-event registered plug-in to a post-event registered plug-in.



using System;
using Microsoft.Crm.Sdk;
using Microsoft.Crm.SdkTypeProxy;

public class AccountSetStatePreHandler : IPlugin
{
public void Execute(IPluginExecutionContext context)
{
// Create or retrieve some data that will be needed by the post event
// handler. You could run a query, create an entity, or perform a calculation.
//In this sample, the data to be passed to the post plug-in is
// represented by a GUID.
Guid contact = new Guid("{74882D5C-381A-4863-A5B9-B8604615C2D0}");

// Pass the data to the post event handler in an execution context shared
// variable named PrimaryContact.
context.SharedVariables.Properties.Add(
new PropertyBagEntry("PrimaryContact", (Object)contact.ToString()));
// Alternate code: context.SharedVariables["PrimaryContact"] = contact.ToString();
}
}

public class AccountSetStatePostHandler : IPlugin
{
public void Execute(IPluginExecutionContext context)
{
// Obtain the contact from the execution context shared variables.
if (context.SharedVariables.Contains("PrimaryContact"))
{
Guid contact =
new Guid((string)context.SharedVariables["PrimaryContact"]);
// Do something with the contact.
}
}
}