I've written a program that edits a specific filetype , and I want to give the user the option to set my application as the default editor for this filetype (since I don't want an installer) on startup.

I've tried to write a re-useable method that associates a file for me (preferably on any OS, although I'm running Vista) by adding a key to HKEY_CLASSES_ROOT, and am using it with my application, but it doesn't seem to work.

  public static void SetAssociation(string Extension, string KeyName, string OpenWith, string FileDescription)
    {
    RegistryKey BaseKey;
    RegistryKey OpenMethod;
    RegistryKey Shell;
    RegistryKey CurrentUser;

    BaseKey = Registry.ClassesRoot.CreateSubKey(Extension);
    BaseKey.SetValue("", KeyName);

    OpenMethod = Registry.ClassesRoot.CreateSubKey(KeyName);
    OpenMethod.SetValue("", FileDescription);
    OpenMethod.CreateSubKey("DefaultIcon").SetValue("", "\"" + OpenWith + "\",0");
    Shell = OpenMethod.CreateSubKey("Shell");
    Shell.CreateSubKey("edit").CreateSubKey("command").SetValue("", "\"" + OpenWith + "\"" + " \"%1\"");
    Shell.CreateSubKey("open").CreateSubKey("command").SetValue("", "\"" + OpenWith + "\"" + " \"%1\"");
    BaseKey.Close();
    OpenMethod.Close();
    Shell.Close();

    CurrentUser = Registry.CurrentUser.CreateSubKey(@"HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.ucs");
    CurrentUser = CurrentUser.OpenSubKey("UserChoice", RegistryKeyPermissionCheck.ReadWriteSubTree, System.Security.AccessControl.RegistryRights.FullControl);
    CurrentUser.SetValue("Progid", KeyName, RegistryValueKind.String);
    CurrentUser.Close();
}