What is major process of delegates ?

Question

what is main reason for introducing delegates and also it is solution for which type problems.i like to know that problem.Thanks in advance

Answer 1

First class functions

Answer 2

You can mostly think of delegates as being like interfaces with a single method. So in places where a language without delegates (such as Java) would use an interface, it makes sense to have a delegate.

Delegates have these benefits over interfaces:

• The implementation can be private, whereas methods implementing interfaces have to be public in Java. (C# has explicit interface implementation as well.)
• You can implement multiple delegates in a single class, or even the same delegate type multiple times
• The framework and language have additional support for delegates:
  • Combining them together (and removing them)
  • A pub/sub framework (events)
  • Background invocation using the thread pool (BeginInvoke etc)
  • Lambda expressions and anonymous methods make them easy to create "inline"
  • Expression trees, representing the logic of an expression in data rather than IL

Delegates are typically used for:

• Event handling, e.g. in GUIs
• Providing "small" pieces of behaviour, e.g. the filters and projections in LINQ
• Callbacks for asynchronous programming

Think of them as a way of encapsulating a single piece of behaviour, and see where that leads you.