Is there a way in .NET to have a method called automatically after another method has been invoked but before it is entered

Question

What I am looking for is a way to call a method after another method has been invoked but before it is entered. Example:

public class Test {

  public void Tracer ( ... )
  {
  }

  public int SomeFunction( string str )
  {
    return 0;
  }

  public void TestFun()
  {
    SomeFunction( "" );
  }

}

In the example above I would like to have Tracer() called after SomeFunction() has been invoked by TestFun() but before SomeFunction() is entered. I'd also like to get reflection data on SomeFunction().

---

I found something interesting in everyone's answers. The best answer to the question is to use Castle's DynamicProxy; however, this is not that I'm going to use to solve my problem because it requires adding a library to my project. I have only a few methods that I need to "trace" so I've chosen to go with a modified "core" methodology mixed with the way Dynamic Proxy is implemented. I explain this in my answer to my own question below.

Just as a note I'm going to be looking into AOP and the ContextBoundObject class for some other applications.

Answer 1

You can use a dynamic proxy (Castle's DynamicProxy for example) to intercept the call, run whatever code you wish, and then either invoke your method or not, depending on your needs.

Answer 2

Use a *Core method:

public int SomeFunction(string str)
{
    Tracer();
    return SomeFunctionCore(str);
}

private int SomeFunctionCore(string str)
{
    return 0;
}

A number of the .NET APIs use this (lots do in WPF).