FairyGUI.InputTextField.ValidateInput C# (CSharp) Method

        string ValidateInput(string source)
        {
            if (_restrict != null)
            {
                StringBuilder sb = new StringBuilder();
                Match mc = _restrictPattern.Match(source);
                int lastPos = 0;
                string s;
                while (mc != Match.Empty)
                {
                    if (mc.Index != lastPos)
                    {
                        //保留tab和回车
                        for (int i = lastPos; i < mc.Index; i++)
                        {
                            if (source[i] == '\n' || source[i] == '\t')
                                sb.Append(source[i]);
                        }
                    }

                    s = mc.ToString();
                    lastPos = mc.Index + s.Length;
                    sb.Append(s);

                    mc = mc.NextMatch();
                }
                for (int i = lastPos; i < source.Length; i++)
                {
                    if (source[i] == '\n' || source[i] == '\t')
                        sb.Append(source[i]);
                }

                return sb.ToString();
            }
            else
                return source;
        }