c#实现数据的左补右补功能

       /// <summary>
        /// 左補右補功能
        /// </summary>
        /// <param name="str">待處理字符串</param>
        /// <param name="expad_type">待補類型（L:左補，R:右補）</param>
        /// <param name="conLength">總長度</param>
        /// <param name="PadChar">補滿內容</param>
        private static void StrPadding(ref string str, string expad_type, int conLength, char PadChar)
        {
            if (str.Length >= conLength)
            {
                str = str.Substring(0, conLength);
            }
            else
            {
                if (expad_type.ToUpper() == "L")
                {
                    str = str.PadLeft(conLength, PadChar);
                }
                else
                {
                    str = str.PadRight(conLength, PadChar);
                }
            }
        }