FUNC <void> 作为输入参数

Question

I have method in c# with some parameters:

public static void DeleteSingleItemInDataGrid
    (DataGrid dataGrid, String IDcolumnName, Func<int> afterCompletionMethod_ToRun)

I want to change third parameter type to Func< void > but I can't. how can I do it?

In other words my question is how can pass a method(or function with void result ) as a method parameter?

Answer 1

A delegate referencing a method that "returns" void is called an Action in .NET lingo, and that's what the delegate type is called as well:

• System.Action Delegate

So your method signature would be this:

public static void DeleteSingleItemInDataGrid
    (DataGrid dataGrid, String IDcolumnName, Action afterCompletionMethod_ToRun)

If you need to pass the int parameter to it, and not return int , it would be this:

public static void DeleteSingleItemInDataGrid
    (DataGrid dataGrid, String IDcolumnName, Action<int> afterCompletionMethod_ToRun)

This accepts a method taking an int parameter, that does not return anything (aka "returning" void ).

This also means that you cannot create a generic method that accepts both methods returning something and methods not returning something with just one method, but need to create an overload using Action , and one using Func<T> .

Answer 2

The Action delegate you can use. It will perform given task and does not return a value.