public static void Example(string userInput)
        {
            string sbc = userInput.ToSBC(); //转全角
            //具体操作，如存入数据库 
            string dbc = userInput.ToDBC();//转半角
            //具体操作，如存入数据库 
        }
        /**//// <summary>
        /// 转全角(SBC case)
        /// </summary>
        /// <param name="input">任意字符串</param>
        /// <returns>全角字符串</returns>
        public static string ToSBC(this string input)
        {
            char[] c = input.ToCharArray();
            for (int i = 0; i < c.Length; i++)
            {
                if (c[i] == 32)
                {
                    c[i] = (char)12288;
                    continue;
                }
                if (c[i] < 127)
                    c[i] = (char)(c[i] + 65248);
            }
            return new string(c);
        }
        /**//// <summary>
        /// 转半角(DBC case)
        /// </summary>
        /// <param name="input">任意字符串</param>
        /// <returns>半角字符串</returns>
        public static string ToDBC(this string input)
        {
            char[] c = input.ToCharArray();
            for (int i = 0; i < c.Length; i++)
            {
                if (c[i] == 12288)
                {
                    c[i] = (char)32;
                    continue;
                }
                if (c[i] > 65280 && c[i] < 65375)
                    c[i] = (char)(c[i] - 65248);
            }
            return new string(c);
        }