CODEWITHSUNDEEP
c#delegates
Valentyn Vynogradskiy
Valentyn Vynogradskiy

Reputation: 653

Delegate inherited methods explanation

Where methods BeginInvoke, Invoke, EndInvoke goes from?

I went to MulticastDelegate and Delegate, and they doesn't contain any methods declarations. Of course I understand that signature of this method depends on delegate declarations. But I can't understand how it works.

Here what John Skeet says about it:

Any delegate type you create has the members inherited from its parent types, one constructor with parameters of object and IntPtr and three extra methods: Invoke, BeginInvoke and EndInvoke. We'll come back to the constructor in a minute. The methods can't be inherited from anything, because the signatures vary according to the signature the delegate is declared with. Using the sample code above, the first delegate has the following methods

I'm not native English speaker and I'm a bit confused with fact that

Any delegate type you create has the members inherited from its parent

but then

The methods can't be inherited from anything

Please explain how it works.

Upvotes: 1

Views: 550

Answers (2)

Selman Genç
Selman Genç

Reputation: 101711

Delegates are special types, that sentence probably means that you can't manually inherit from Delegate or MulticastDelegate class because they are special classes.So the C# compiler creates types that inherits from MulticastDelegate and declares those methods according to the signature of delegate type automatically.

Or possibly, it means that since the delegate type changes the signatures of those methods, they are not inherited but instead they created by compiler from scratch, depending on the type of the delegate.(after re-reading, this makes more sense).

Upvotes: 0

oleg wx
oleg wx

Reputation: 296

When the compiler processes the C# delegate type it automatically generates a sealed class deriving from System.MulticastDelegate.

sealed class Add : System.MulticastDelegate
{
   public int Invoke(int x, int y);
   public IAsyncResult BeginInvoke(int x, int y, AsyncCallback cb, object state);
   public int EndInvoke(IAsyncResult result);
}

QuiteCode

Upvotes: 0

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