如何将任何方法作为另一个函数的参数传递

Question

In class A, I have

internal void AFoo(string s, Method DoOtherThing)
{
    if (something)
    {
        //do something
    }
    else
        DoOtherThing();
}

Now I need to be able to pass DoOtherThing to AFoo() . My requirement is that DoOtherThing can have any signature with return type almost always void. Something like this from Class B,

void Foo()
{
    new ClassA().AFoo("hi", BFoo);
}

void BFoo(//could be anything)
{

}

I know I can do this with Action or by implementing delegates (as seen in many other SO posts) but how could this be achieved if signature of the function in Class B is unknown??

Answer 1

You need to pass a delegate instance; Action would work fine:

internal void AFoo(string s, Action doOtherThing)
{
    if (something)
    {
        //do something
    }
    else
        doOtherThing();
}

If BFoo is parameterless it will work as written in your example:

new ClassA().AFoo("hi", BFoo);

If it needs parameters, you'll need to supply them:

new ClassA().AFoo("hi", () => BFoo(123, true, "def"));

Answer 2

Use an Action or Func if you need a return value.

Action: http://msdn.microsoft.com/en-us/library/system.action.aspx

Func: http://msdn.microsoft.com/en-us/library/bb534960.aspx

Answer 3

public static T Runner<T>(Func<T> funcToRun)
{
    //Do stuff before running function as normal
    return funcToRun();
}

Usage:

var ReturnValue = Runner(() => GetUser(99));

I use this for error handling on my MVC site.