// Starts Windows Explorer with two different command line arguments.
      ProcessStartInfo startInfo = new ProcessStartInfo("explorer.exe");

        // Opens a new single-pane Window for the default selection.
        // This is usually the root of the drive on which Windows is installed.

      startInfo.Arguments = "/n";         //  或 直接指定 資料夾路徑    startInfo.Arguments = "C:\\TEST\\";        

        Process.Start(startInfo);