What is the difference between delegate in c# and

问题:

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Closed 8 years ago.

Possible Duplicate:
are there function pointers in c#?

I'm interested in finding the difference between delegate in C# and function pointer in C++.

回答1:

A delegate in C# is a type-safe function pointer with a built in iterator.

It's guaranteed to point to a valid function with the specified signature (unlike C where pointers can be cast to point to who knows what). It also supports the concept of iterating through multiple bound functions.

In C#, delegates are multi-cast meaning they can iterate through multiple functions. For example:

class Program
{
   delegate void Foo();

   static void Main(string[] args)
   {
      Foo myDelegate = One;
      myDelegate += Two;

      myDelegate(); // Will call One then Two
   }

   static void One()
   {
      Console.WriteLine("In one..");
   }

   static void Two()
   {
      Console.WriteLine("In two..");
   }
}

回答2:

Delegates in C# can be either synchronous or asynchronous; C++ function pointers are synchronous unless you write your own multi-threading capability.

A pointer in C/C++ needn't refer to a full-blown object. C had function pointers and no object-oriented language support. Delegates are true function objects.