Shaping up to be a busy busy week at work this (and many to come for that matter), but here's a short little nugget of coolness that I came across today while working on a custom wrapper class for the System.Diagnostic.Trace class. I'll probably write a longer post about that later actually, cause there's some really cool stuff you can do with  TraceListeners and its friends. Anyways, I wanted to append the (fully classified) name of the method that was responsible for logging any given message. Obviously, I could request that the caller sent its name as a string to my log method, but where's the finesse in that?

A bit of digging around, and I found just what I wanted - the StackTrace and StackFrame classes. Basically, they'll let you walk the current stack trace - you know, that gibberish exceptions scream at you whenever they get a chance, or Visual Studio lists in its Call Stack window when stepping through a program:

So then, to get the name of the method that called my log method (the 'caller'), I could just get the StackFrame one level up. Here's a simplistic example which just prints the log message to the console, appended by the name of the caller:

public static void Log(string message)
{
StackFrame frame = new StackFrame(1);
MethodBase method = frame.GetMethod();
message = String.Format("{0}.{1} : {2}",
method.DeclaringType.FullName, method.Name, message);
Console.WriteLine(message);
}

Pretty cool, yes? Okay, now for the bad news:

You can't really depend on this for anything other than Debug builds. Once you build your application in Release mode, the compiler may very well decide to optimize your code by inlining some of the methods. Additionally, any native calls (f.ex stuff in mscorelib) will not show up in the stack trace. And also, cross-threading will ruin it too. Mike Stall has a post detailing some of these issues, with an example of inlining.

So yeah, there's a few caveats here that basically renders this approach useless for anything but debugging. But then its quite cool, and you can also get alot of other information about the current frame - especially if you have the debug symbols loaded.