Tip #83: Did you know... You can get the name of the calling method from the stack using reflection?

Nearly every program needs a logger to log events, errors and exceptions. Sometimes it is also useful to log the name of the method that logged the event. The easiest way to do that is to make the log method take both the calling method name and event as parameters:

[C#]

 void Log(string callingMethodName, string eventMessage) 

{   
   Console.WriteLine("Event logged by " + callingMethodName);  
   Console.WriteLine("Event: " + eventMessage); 

}

In this case, every method will need to specify its name when calling Log(). In addition to this, the developer will have to watch if methods name change. However, there is a cleaner way to get the name of the calling method. It can be extracted from the stack. Since the method on top of the stack is the method that is currently being executed, the calling method will be right below it. Thus, by instantiating StackTrace (don’t forget to include System.Diagnostics) and getting the frame with index 1 will result in getting a StackFrame that corresponds to the call from the calling method. Finally, reflection can be used to get method name.

 using System.Diagnostics;
    
void Log(string eventMessage)
{ 

   Console.WriteLine("Event logged by " + (new StackTrace()).GetFrame(1).GetMethod().Name); 

   Console.WriteLine("Event: " + eventMessage);

}

Katerina Rohonyan
SDET, IIS Team

Comments

• Anonymous
  June 23, 2009
  Indeed, StackTrace.GetFrame.GetMethod is nice for tose things. However, beware that an optimizing compiler might optimize away stackframes (due to inlining for example). In .NET you can add a JIT attribute ([Runtime.CompilerServices.MethodImpl(Runtime.CompilerServices.MethodImplOptions.NoInlining)]) but that only instructs the JIT to not inline. The C# compiler can not be told to not inline (but it does not seem to inline currently).

• Anonymous
  June 24, 2009
  The comment has been removed

• Anonymous
  June 24, 2009
  The comment has been removed

• Anonymous
  June 24, 2009
  I just instinctively reference log4net, even for simple little on-off tools. You can log calling method amongst a hundred other attributes, just by configuring a format string.

• Anonymous
  June 25, 2009
  How can you get the called method from the constructor?

• Anonymous
  June 26, 2009
  The comment has been removed