How do I convert a string of the form %programfiles%\directory\tool.exe to a useable Filename in C#/.net?

Question

I have an application which takes a string value of the form %programfiles%\directory\tool.exe from its application config file.

I want to make this into a useable filename so that I can call

System.Diagnostics.Process.Start(filename)

and have it execute the application. I'm curently getting a System.ComponentModel.Win32Exception - The system cannot find the file specified

Many thanks for any help with this.

Answer 1

filename = Environment.ExpandEnvironmentVariables(filename);