How to remove illegal characters from path and filenames?

Question

I need a robust and simple way to remove illegal path and file characters from a simple string. I\'ve used the below code but it doesn\'t seem to do anything, what am I miss

Answer 1

The original question asked to "remove illegal characters":

public string RemoveInvalidChars(string filename)
{
    return string.Concat(filename.Split(Path.GetInvalidFileNameChars()));
}

You may instead want to replace them:

public string ReplaceInvalidChars(string filename)
{
    return string.Join("_", filename.Split(Path.GetInvalidFileNameChars()));    
}

This answer was on another thread by Ceres, I really like it neat and simple.