C#字符串按指定长度换行

         /// <summary>
        /// 字符串按指定长度换行
        /// </summary>
        /// <param name="conten">字符串</param>
        /// <param name="start">指定长度</param>
        /// <param name="sSymbol">换行符</param>
        /// <returns>按指定长度换行后的字符串</returns>
        public static string SqritBySymbol(string conten,int start,string sSymbol)
        {
            string str = "";
            char[] param = conten.ToCharArray();
            if (param.Length > 0) {

                if (param.Length > start) 
                {
                    int j = 1;
                    for (int i = 0; i < param.Length; i++ ) 
                    {
                        str +=param[i];
                        if (i==(start*j)) 
                        {
                            j++;
                            str = str + sSymbol;
                        }
                    }
                }
            }
            return str;
        }