一个字符串截取算法

 

           

      

       string GetString = "";  //返回截取的字符
        int count = 0;   //截取的次数
        string retString = ""; //返回截取后剩余的字符
        /// <summary>
       /// 创建Winform程序添加4个TextBox和 一个Button按钮
        /// TextBox1输入要截取的字符
        /// TextBox3输入要截取的字符长度
        /// TextBox4输入截取的次数
        /// </summary>
       /// <param name="sender"></param>
       /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {

            int a = Convert.ToInt32(textBox3.Text); //要截取的字符长度
            int b = Convert.ToInt32(textBox4.Text); //截取的次数

            retString = textBox1.Text;

            for (int i = 1; i <= b; i++)
            {
                textBox2.Text = GetStrString(retString, a, i);
            }
        }
        /// <summary>
        /// 循环截取字符串
         /// </summary>
        /// <param name="str">截取的字符串</param>
        /// <param name="len">截取的长度</param>
        /// <param name="temp">截取的次数</param>
        /// <returns></returns>
        private string GetStrString(string str, int len, int temp)
        {
            count++;

            if (Encoding.GetEncoding("shift-jis").GetByteCount(str.Trim()) > len)
            {
                string SubString = str;

                if (Encoding.GetEncoding("shift-jis").GetByteCount(SubString.Trim()) > len)
                {
                    int a = Encoding.GetEncoding("shift-jis").GetByteCount(SubString);
                    int length = SubString.Trim().Length;

                    for (int i = length; i > 0; i--)
                    {
                        if (Encoding.GetEncoding("shift-jis").GetByteCount(SubString.Trim().Substring(0, i).Trim()) <= len)
                        {
                            if (count == temp)
                            {
                                GetString = SubString.Trim().Substring(0, i);
                                retString = SubString.Trim().Substring(i);
                                count = 0;
                                break;
                            }
                            else
                            {
                                GetString = SubString.Trim().Substring(0, i);
                                retString = SubString.Trim().Substring(i);
                                count = 0;
                                break;
                            }
                        }
                    }
                }
                else
                {
                    GetString = str.Substring(0, len);
                    count = 0;
                }
            }
            else
            {
                GetString = str;
                count = 0;
            }
            return GetString.ToString(); ;
        }

 写的不好请大家多多指教