C# Any function as parameter

Question

Is it possible to created a method that takes ANY method (regardless of it's parameters) as a parameter? The method would also have a params parameter which then takes all the parameters for the parameter-method.

So basically what I want is something like this:

public void CallTheMethod(Action<int> theMethod, params object[] parameters)

But then for any method, not just for methods that takes an int.

Is something like this possible?

Thanks

Answer 1

It's possible, but not what should be done.

This is what I would do:

public void CallTheMethod(Action toCall)

You might go "huh". Basically, what it lets the user do is this:

CallTheMethod(() => SomeOtherMethod(with, some, other, parameters));

However, if you want it to return a type, it involves generics:

public void CallTheMethod<T>(Func<T> theMethod)

You can put generic constraints on that type, do whatever you want with it, etc.

Answer 2

Yes, with a delegate:

public object CallTheMethod(Delegate theMethod, params object[] parameters)
{
    return theMethod.DynamicInvoke(parameters);
}

But see Marc Gravell's comment on your question :)

Well, you could pass the non-specific Delegate, but DynamicInvoke is sloooooowwwwww (relatively speaking)

Answer 3

Yes. You can use DynamicInvoke to call the methods:

Action<int> method1 = i => { };
Func<bool, string> method2 = b => "Hello";

int arg1 = 3;
bool arg2 = true;
//return type is void, so result = null;
object result = method1.DynamicInvoke(arg1);

//result now becomes "Hello";
result = method2.DynamicInvoke(arg2);

A method to do this would become:

object InvokeMyMethod(Delegate method, params object[] args)
{
    return method.DynamicInvoke(args);
}

Answer 4

You can use Delegate and DynamicInvoke to do this, although just like what other people said, it's slow.

If you get error Cannot convert from 'method group' to 'System.Delegate', you may need to cast it when passing the function as argument. For example if you have:

public static void registerMethod(Delegate method, params object[] parameters) {
    var ret = method.DynamicInvoke(parameters);
    // ...
}

public static long myAdditionMethod(int a, int b){
    return a+b;
}

then you can call the function like this:

registerMethod((Func<int, int, long>)myAdditionMethod, 1, 2)

Or you can also use Action<> instead of Func<> if the method's return type is void.

Note: The solution above is not always required. Depending on your C# project configuration, you can just simply call registerMethod(myAdditionMethod, 1, 2) without getting any compilation error.