How do I pass a function pointer delegate for a different class in c#

Question

In c++, To a function that takes in a function pointer with void return type, eg:

void TakesFun(Func<void ()>  fun ){
    fun();
}

Above function can be called in these ways

//if foo is a function returning void but is declared in global space and not part of another class
TakesFun(bind(foo));   
//if foo is a function returning void but is declared in class called ClassX and the function is required to be called for object "obj".
TakesFun(bind(ClassX::foo, obj));   
//if foo is a function taking an integer as argument and returning void but is declared in class called ClassX and the function is required to be called for object "obj".
TakesFun(bind(ClassX::foo, obj, 5)); //5 is the argument supplied to function foo

Could you help me write C# code for 3 similar function calls? I tried reading up on Delegates, but the examples do not cover all the above 3 cases.

vasily.sib · Accepted Answer · 2018-06-18 05:04:43Z

2

As @Backs said, you can define TakesFun function like this:

void TakesFun(Action action) => action();

If you need to pass a parameter, you can use this:

void TakesFun<TParam>(Action<TParam> action, TParam p) => action(p);

Your 3 examples will be:

TakesFun(SomeClass.Foo); // 'Foo' is a static function of 'SomeClass' class
TakesFun(obj.Foo); // 'Foo' is a function of some class and obj is instance of this class
TakesFun(obj.Foo, "parameter"); // as above, but will pass string as parameter to 'Foo'

answered Jun 18, 2018 at 5:04

vasily.sib

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2 Comments

sgowd Over a year ago

Could I make the syntax of TakesFun be able to take any number of arguments for the action?

vasily.sib Over a year ago

Sure, with a little trick, see this SO question

Backs · Accepted Answer · 2018-06-18 04:36:23Z

0

You can always pass an Action:

void TakesFun(Action action)
{
    action();
}
///...
TestFun(() => SomeMethod(1,2,3));

answered Jun 18, 2018 at 4:36

Backs

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