How do you get the current project directory from C# code when creating a custom MSBuild task?

Instead of running an external program with its path hardcoded, I would like to get the current Project Dir. I'm calling an external program using a process in the custom task.

How would I do that? AppDomain.CurrentDomain.BaseDirectory just gives me the location of VS 2008.

using System;
using System.IO;

// This will get the current WORKING directory (i.e. \bin\Debug)
string workingDirectory = Environment.CurrentDirectory;
// or: Directory.GetCurrentDirectory() gives the same result

// This will get the current PROJECT bin directory (ie ../bin/)
string projectDirectory = Directory.GetParent(workingDirectory).Parent.FullName;

// This will get the current PROJECT directory
string projectDirectory = Directory.GetParent(workingDirectory).Parent.Parent.FullName;

You can try one of this two methods.

string startupPath = System.IO.Directory.GetCurrentDirectory();

string startupPath = Environment.CurrentDirectory;

Tell me, which one seems to you better