截字符函数

   //截取字符串函数
        public static string CutString(string inputString, int len)
        {
            System.Text.ASCIIEncoding ascii = new System.Text.ASCIIEncoding();
            int tempLen = 0;
            string tempString = "";
            byte[] s = ascii.GetBytes(inputString);
            for (int i = 0; i < s.Length; i++)
            {
                int n = int.Parse((s[i]).ToString());
                if (n == 63)
                {
                    tempLen += 2;
                }
                else
                {
                    tempLen += 1;
                }

                try
                {
                    tempString += inputString.Substring(i, 1);
                }
                catch
                {
                    break;
                }

                if (tempLen > len)
                    break;
            }

            // 如果截过则加上半个省略号
            //byte[] mybyte = System.Text.Encoding.Default.GetBytes(inputString);
            //if (mybyte.Length > len)
            //    tempString += " …";

            return tempString;
        }