How can I get all filenames of a directory (and its subdirectorys) without the full path? Directory.GetFiles(...) returns always the full path!
You want Path.GetFileName
This returns just the filename (with extension).
If you want just the name without the extension then use Path.GetFileNameWithoutExtension
string fileName = @"C:\mydir\myfile.ext";
string path = @"C:\mydir\";
string result;
result = Path.GetFileName(fileName);
Console.WriteLine("GetFileName('{0}') returns '{1}'",
fileName, result);
result = Path.GetFileName(path);
Console.WriteLine("GetFileName('{0}') returns '{1}'",
path, result);