c# 替换所有中文、标点符号，全角转半角

 　　　　private void btnStart_Click(object sender, EventArgs e)
        {
            var srcWords = ToDBC(txtSrc.Text.Trim());
            var placeStr = Regex.Replace(srcWords, @"([\p{P}*])", " ");
            placeStr = Regex.Replace(placeStr,@"([\u4e00-\u9fa5])", "");
            var splitWords = placeStr.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);
            var words = splitWords.ToList().Select(item =>
            {
                if (item.Length > )
                {
                    var first = item.Substring(, ).ToUpper();
                    var last = "";
                    if (item.Length > )
                    {
                        last = item.Substring(, item.Length-);
                    }
                    return first + last;
                }
                return "";
            });
            var joinWords = string.Join(" ", words);
            Clipboard.SetText(joinWords);

            txtDes.Text = AppendWords(joinWords);
            MessageBox.Show("已将替换后的字符串复制到粘贴板");
        }

        /// <summary>
        /// 替换所有的中文及标点符号
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        string RemoveAllChineseAndSymbol(string str)
        {
            var placeStr = Regex.Replace(str, @"([\p{P}*])", " ");
            placeStr = Regex.Replace(placeStr, @"([\u4e00-\u9fa5])", "");
            return placeStr;
        }
        /// <summary>
        /// 追加及替换内容
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        string AppendWords(string str)
        {
            var append = Regex.Replace(ToDBC(txtAppend.Text.Trim()), @"[\p{P}*]", " ");
            if (string.IsNullOrEmpty(append))
            {
                return str;
            }
            var i=combSelect.SelectedIndex;

            if (i==)
            {
                return str.Trim() + " " + append;
            }else if (i==)
            {
                return append + " " + str.Trim();
            }else if (i==)
            {
                var replaceTo=Regex.Replace(ToDBC(txtToReplace.Text.Trim()), @"[\p{P}*]", " ");
                return str.Trim().Replace(append, replaceTo);
            }
            else
            {
                return str;
            }
        }
        /// <summary>
        /// 全角转半角
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public string ToDBC(string input)
        {
            char[] c = input.ToCharArray();
            for (int i = ; i < c.Length; i++)
            {
                if (c[i] == )
                {
                    c[i] = (char);
                    continue;
                }
                if (c[i] >  && c[i] < )
                    c[i] = (char)(c[i] - );
            }
            return new String(c);
        }

        private void combSelect_SelectedIndexChanged(object sender, EventArgs e)
        {
            var cb=(ComboBox) sender;
            txtToReplace.Visible = cb.SelectedIndex==;
        }