what is delegates and why we use delegates?explain in detail

A Delegate is an abstraction of one or more function pointers. The .NET has implemented the concept of function pointer in form delegate .With delegates; you can treat a function as data. Delegates allow function to be passed as parameters, returned from a function as value and stored in an array. The delegate has following characteristics.

§ Delegates are derived from System.MulticastDelegate class.

§ They have a signature and a return type. A function that is added to delegates must be compatible with this signature.

§ Delegates can point either static or instance methods.

§ Once a delegate object has been created, it may dynamically invoke the methods it points to at runtime.

§ Delegates can call methods synchronously and asynchronously.

The delegate contains a couple of useful fields. The first one holds a reference to an object, and the second holds a method pointer. When you invoke the delegate, the instance method is called on the contained reference. However, if the object reference is null, the runtime understands this to mean that the method is a static method. Moreover, invoking a delegate syntactically is the exact same as calling a regular function. Therefore, delegates are perfect for implementing callbacks.

A delegate is a type that represents references to methods with a particular parameter list and return type. When you instantiate a delegate, you can associate its instance with any method with a compatible signature and return type. You can invoke (or call) the method through the delegate instance.
Delegates are used to pass methods as arguments to other methods. Event handlers are nothing more than methods that are invoked through delegates. You create a custom method, and a class such as a windows control can call your method when a certain event occurs. The following example shows a delegate declaration:
public delegate int PerformCalculation(int x, int y);

refer this..

http://msdn.microsoft.com/en-IN/library/ms173171.aspx

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Ajay Yadav12y ago
A Delegate is an abstraction of one or more function pointers. The .NET has implemented the concept of function pointer in form delegate .With delegates; you can treat a function as data. Delegates allow function to be passed as parameters, returned from a function as value and stored in an array. The delegate has following characteristics.

§ Delegates are derived from System.MulticastDelegate class.
§ They have a signature and a return type. A function that is added to delegates must be compatible with this signature.
§ Delegates can point either static or instance methods.
§ Once a delegate object has been created, it may dynamically invoke the methods it points to at runtime.
§ Delegates can call methods synchronously and asynchronously.

The delegate contains a couple of useful fields. The first one holds a reference to an object, and the second holds a method pointer. When you invoke the delegate, the instance method is called on the contained reference. However, if the object reference is null, the runtime understands this to mean that the method is a static method. Moreover, invoking a delegate syntactically is the exact same as calling a regular function. Therefore, delegates are perfect for implementing callbacks.
Yadagiri Reddy12y ago
A delegate is a type that represents references to methods with a particular parameter list and return type. When you instantiate a delegate, you can associate its instance with any method with a compatible signature and return type. You can invoke (or call) the method through the delegate instance.
Delegates are used to pass methods as arguments to other methods. Event handlers are nothing more than methods that are invoked through delegates. You create a custom method, and a class such as a windows control can call your method when a certain event occurs. The following example shows a delegate declaration:
public delegate int PerformCalculation(int x, int y);

refer this..

http://msdn.microsoft.com/en-IN/library/ms173171.aspx