[c#] Func delegate with no return type

All of the Func delegates return a value. What are the .NET delegates that can be used with methods that return void?

... takes no arguments and has a void return type?

If you are writing for System.Windows.Forms, You can also use:

public delegate void MethodInvoker()

... takes no arguments and has a void return type?

I believe Action is a solution to this.

All of the Func delegates take at least one parameter

That's not true. They all take at least one type argument, but that argument determines the return type.

So Func<T> accepts no parameters and returns a value. Use Action or Action<T> when you don't want to return a value.

Occasionally you will want to write a delegate for event handling, in which case you can take advantage of System.EvenHandler<T> which implicitly accepts an argument of type object in addition to the second parameter that should derive from EventArgs. EventHandlers will return void

I personally found this useful during testing for creating a one-off callback in a function body.

A very easy way to invoke return and non return value subroutines. is using Func and Action respectively. (see also https://msdn.microsoft.com/en-us/library/018hxwa8(v=vs.110).aspx)

Try this this example

using System;

public class Program
{
    private Func<string,string> FunctionPTR = null;  
    private Func<string,string, string> FunctionPTR1 = null;  
    private Action<object> ProcedurePTR = null; 



    private string Display(string message)  
    {  
        Console.WriteLine(message);  
        return null;  
    }  

    private string Display(string message1,string message2)  
    {  
        Console.WriteLine(message1);  
        Console.WriteLine(message2);  
        return null;  
    }  

    public void ObjectProcess(object param)
    {
        if (param == null)
        {
            throw new ArgumentNullException("Parameter is null or missing");
        }
        else 
        {
            Console.WriteLine("Object is valid");
        }
    }


    public void Main(string[] args)  
    {  
        FunctionPTR = Display;  
        FunctionPTR1= Display;  
        ProcedurePTR = ObjectProcess;
        FunctionPTR("Welcome to function pointer sample.");  
        FunctionPTR1("Welcome","This is function pointer sample");   
        ProcedurePTR(new object());
    }  
}

Try System.Func<T> and System.Action