C#中转换全半角字符的函数

/**////
        /// 转全角的函数(SBC case)
        ///
        /// 任意字符串
        /// 全角字符串
        ///
        ///全角空格为12288，半角空格为32///其他字符半角(33-126)与全角(65281-65374)的对应关系是：均相差65248
        ///       
        public string ToSBC(string input)
        {
            //半角转全角：
            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);               
        }

        /**////
        /// 转半角的函数(DBC case)
        ///
        /// 任意字符串
        /// 半角字符串
        ///
        ///全角空格为12288，半角空格为32
        ///其他字符半角(33-126)与全角(65281-65374)的对应关系是：均相差65248
        ///
        public string ToDBC(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);
         &n