Find out on which type a static method was called

Question

I have a class A with a static method, and a derived class B. You can call Foo(), declared in A, on both A and B:

public class A
{
    public static void Foo() 
    {
       // How to get typeof(B) here if Foo called by using class B? 
    }
}

public class B : A
{
}

...

static class Program
{
    static void Main()
    {
        B.Foo();
    }
}

Now inside Foo(), how can I find out on which type Foo() was called?

I can't use keyword this, because I do not create any objects here. I have tried already:

MethodBase.GetCurrentMethod().DeclaringType

and

MethodBase.GetCurrentMethod().ReflectedType

but they both return me the typeof(A), while I need to get the typeof(B).

@Alfie Goodacre, Stacktrace looks like a "dirty trick", so I did not try it yet. — Ceridan, May 23 '17 at 09:35
The stack trace wouldn't make any difference, as despite the wording of the question, this isn't about the *caller* (which is `Program.Main`), it's about the target class of the static method invocation. — Jon Skeet, May 23 '17 at 09:39
Can you explain _why_ you need to find out on which type a static method was called? — CodeCaster, May 23 '17 at 09:41
@CodeCaster, I have a lot of "B" classes inherited from the common parent A. B classes have some attributes and my static method should analyze this attributes using reflection for each B class and return some info. Yes, I can make a parameter in the static method and use it for example like this: A.Foo(typeof(B)); A.Foo(typeof(C)); and so on, but B.Foo() is easier to read and write. This is not a big problem in my code. I asked this question to understand the situation in general. — Ceridan, May 23 '17 at 09:49
Jon Skeet and CodeCaster helped me to understand this situation and the answer to my question is simple: you can't. We could close this topic. What should I do: post an answer to the topic by myself or just leave it? — Ceridan, May 23 '17 at 10:00
I'm trying to find the relevant part of the C# spec, but can't find it. The problem is that `B.Foo()` gets compiled to `A.Foo()`, but I can't find any source for why that happens. So feel free to post a self-answer stating you can't do this. — CodeCaster, May 23 '17 at 10:03

score 0 · Answer 1 · answered May 23 '17 at 09:43

0

I'm not sure exactly what you want to achieve, and agree with the comments that perhaps you can approach this a different way. Saying this, could you do what you need with a generic base class?

public class AB<T>
{
    public static void Foo()
    {
        Console.WriteLine(typeof(T));
    }
}

public class A : AB<A> { }

public class B : AB<B> { }

A.Foo(); // A
B.Foo(); // B

answered May 23 '17 at 09:43

TVOHM

2,740
1
19
29

So create a wrapper class just for pointing out on which type you want to call a static method? Note that static methods can't implement interfaces, so you can't call `T.Foo()` inside your `Foo()`. – CodeCaster May 23 '17 at 09:45
Adding a Type parameter is much cleaner than enforcing a generic class. – Tanveer Badar Apr 01 '18 at 15:20

Ceridan · Answer 2 · 2017-05-23T12:23:25.373

0

There are no way to obtain typeof(B) inside of static method Foo() in this case. The possible solution is to use parameters in Foo method.

Thanks to @Jon Skeet and @CodeCaster.

edited May 23 '17 at 12:23

answered May 23 '17 at 10:10

Ceridan

2,376
3
23
32

Find out on which type a static method was called

2 Answers2