自定义asp.net2.0权限提供程序SqlMembershipProvider

        public override bool ChangePassword(string username, string oldPassword, string newPassword)
        {
            SecUtility.CheckParameter( ref username, true, true, true, 256, "username" );
            SecUtility.CheckParameter( ref oldPassword, true, true, false, 128, "oldPassword" );
            SecUtility.CheckParameter( ref newPassword, true, true, false, 128, "newPassword" );

            string salt = null;
            int passwordFormat;
            int status;

            if (!CheckPassword( username, oldPassword, false, false, out salt, out passwordFormat))
            {
               return false;
            }

            if( newPassword.Length < MinRequiredPasswordLength )
            {
                throw new ArgumentException(SR.GetString(
                              SR.Password_too_short,
                              "newPassword",
                              MinRequiredPasswordLength.ToString(CultureInfo.InvariantCulture)));
            }

            int count = 0;

            for( int i = 0; i < newPassword.Length; i++ )
            {
                if( !char.IsLetterOrDigit( newPassword, i ) )
                {
                    count++;
   &nbs