what is Delegate and when to use it? [closed]

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i have searched on the Google but could not find exactly what the delegate is and when to use delegate? can any one explain me with an example?

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You can get it cleared here :

What : http://csharpindepth.com/Articles/Chapter2/Events.aspx

when : http://msdn.microsoft.com/en-us/magazine/cc301810.aspx

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A delegate is kind of like a callback, but it allows you to register more than one callback action.

Maybe an example is easier: you have an OnClick delegate. By default, nothing happens. But you can register 1, or 2, or N callbacks which will ALL receive the OnClick event.

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Delegate is a concept related to Delegation Design Pattern. Let me point you to the wiki link so you can take over the study from there.

http://en.wikipedia.org/wiki/Delegation_pattern

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In simplest terms, a delegate is just like a function assigned to a variable (I'm not sure if that's really what happens under the hood but it helps to think of it like that). If you have programmed in C++, its like the address of a function or the return value of GetProcAddress() but with more functionality and typesafety.

You can call the delegate like regular function, pass it as a function argument (like a regular variable) and it can also be null. Google it again (or visit the links of other posters), there are lots of materials about delegates.