How could I know that BeginAcceptSocket callback needs IAsyncResult parameter?

Question

Hi, I am curious where can I find out that AcceptClient as a callback of BeginAcceptSocket needs to have IAsyncResult as a parameter. In the MSDN article there is only mentioned that return value of BeginAcceptSocket is IAsyncresult. But how could I know that it has to be passed to callback? Thanks!

     public server(int port)
    {
        listener = new TcpListener(System.Net.IPAddress.Any, port);
        listener.BeginAcceptSocket(this.AcceptClient,null);

    }
    private void AcceptClient(IAsyncResult ar)
    {
    }

Answer 1

http://msdn.microsoft.com/en-us/library/system.net.sockets.tcplistener.beginacceptsocket.aspx

The parameters section tells you that the first parameter expects a System.AsyncCallback, which is a delegate that expects an argument of type System.IAsyncResult.

Answer 2

From its documentation, you know that BeginAcceptSocket expects an AsyncCallback as its first parameter, so the next step is to read the documentation for the AsyncCallback delegate, which is itself a type with the following method signature:

public delegate void AsyncCallback(IAsyncResult ar)