How the static class's static method will know the caller?

Question

Imagine I have a static class and a static method inside that. And it has to be accessed by 10 different classes. But how the static class will know who has called it :(

It was an interview question....please rephrase it properly and answer me, I am new :(

OP did not state that the child classes are children of the static class. — Mare Infinitus, Jul 21 '12 at 17:06
this may help you - http://stackoverflow.com/questions/97193/can-i-get-calling-instance-from-within-method-via-reflection-diagnostics — Alex, Jul 21 '12 at 17:06
In c# vNext, caller-attributes might help, but can be spoofed trivially - not a security feature! http://msdn.microsoft.com/en-us/library/hh534540(v=vs.110).aspx — Marc Gravell, Jul 21 '12 at 17:09
@MareInfinitus: lol I didn't give an answer properly, I just told him that, it creates one instance only and not necessary to know who has called :P I am really new buddy :( — Jasmine, Jul 21 '12 at 17:50
@Xander: Uhmm not child class, I meant, any class member that uses this static class method... :( — Jasmine, Jul 21 '12 at 17:51

score 2 · Answer 1 · answered Jul 21 '12 at 17:17

2

As C# does not have a proper metaobject system, the only way I know of is via reflection. The following idea should give the idea:

public static string GetCaller()
{
    var trace = new StackTrace(2);
    var frame = trace.GetFrame(0);
    var caller = frame.GetMethod();
    var callingClass = caller.DeclaringType.Name;
    var callingMethod = caller.Name;
    return String.Format("Called by {0}.{1}", callingClass, callingMethod);
}

answered Jul 21 '12 at 17:17

Stefan Nobis

957
4
12

Thank you Stefan. But I got the result for your program as " Called by AppDomain.nExecuting Assembly" :( – Jasmine Jul 21 '12 at 18:13
The above code should show you the idea. Play with the parameters. The most important one is the parameter to the constructor of StackTrace. Try for example `var trace = new StackTrace(1)`. And have a look at the documentation for the constructor. – Stefan Nobis Jul 22 '12 at 15:42
For me, StackTrace stackTrace = new StackTrace(); var method = stackTrace.GetFrame(1).GetMethod(); was working. From the method (above "caller") you can use above example again. – Andreas Reiff May 31 '23 at 12:13

Mare Infinitus · Accepted Answer · 2012-07-21T17:17:30.280

1

I would try the following:

public class ParentClass
{
}

public class ChildClass :  ParentClass
{
}

public static class StaticClass
{
    public static void SomeMethod(ParentClass d)
    {
        var t = d.GetType();
    }
}

public class StaticChildren
{
    public void Children()
    {
        var p = new ChildClass();

        StaticClass.SomeMethod(p);

    }
}

Just passing an instance is the simplest you can do here.

edited Jul 21 '12 at 17:17

answered Jul 21 '12 at 17:12

Mare Infinitus

8,024
8
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113

I probably would use an object since this will be called from 10 different classes – Mark Hall Jul 21 '12 at 17:14
What the heck? Edited in the complete example, this works for all subclasses of course. – Mare Infinitus Jul 21 '12 at 17:17
@MareInfinitus: You rock ;) Cool thank you so much, but tell me, why it gives me the type as "test.Program+derived+ChildClass" ? I know test.program is my class. But I dont get what is derived and why + and all comes here :( Also I have a doubt, I made this staticchildren class as static, and its member "Children" also static and I saw no difference when I just declared the method "Children" as static...How it differs in performance ? – Jasmine Jul 21 '12 at 18:09
@MareInfinitus: Hey I observed, if the type is not of Parentclass, as obviously, if I have any other class, it doesnt works ....What do you suggest for an optimized solution in this case ? – Jasmine Jul 21 '12 at 18:44
@MareInfinitus: Absolutely right,I then used object it worked right perfectly. Thanks a lot :) Cheers – Jasmine Jul 21 '12 at 19:15

score 0 · Answer 3 · answered Jul 21 '12 at 17:06

You could use the stracktace to find out who called the static method!

class Foo
{
  public void static staticMethod()
  {
    // here i want to know who called me!
    StackTrace st = new StackTrace();
    ...
  }
}

class Bar
{
  public void Bar()
  {
    Foo.staticMethod();
  }
}

score 0 · Answer 4 · answered Jul 21 '12 at 17:07

0

In these cases you can use Reflection.

Find more about reflection under these links: http://www.csharp-examples.net/reflection-calling-method-name/

http://msdn.microsoft.com/en-us/library/ms173183(v=vs.80).aspx

answered Jul 21 '12 at 17:07

eridanix

818
1
8
27

score 0 · Answer 5 · answered Jul 21 '12 at 18:14

0

If the functionality of a method is dependent on who called it, then the design is probably not very good. I'd introduce new parameters instead.

for debugging purposes, a stack trace?

answered Jul 21 '12 at 18:14

Erix

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How the static class's static method will know the caller?

5 Answers5

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