怎样进行域用户验证

public static bool IsUserValid(string ADPath, string UserName, string Password)
{
    System.DirectoryServices.DirectoryEntry de = new System.DirectoryServices.DirectoryEntry(ADPath, UserName, Password, System.DirectoryServices.AuthenticationTypes.Secure);
    try
    {
        Object native = de.NativeObject;
        return true;
    }
    catch
    {
        return false;
    }
}