C# 替換文字檔中的某一行 （要求此檔案存在）

     /// <summary>       /// LineIndex 表示新的內容所在的行位置       /// </summary>       /// <param name="sFileName"></param>       /// <param name="sOrigionContent"></param>       /// <param name="sNewLineContent"></param>       /// <param name="LineIndex"></param>       public static void SaveTxtReplaceOneLine(string sFileName, string sOrigionContent, string sNewLineContent, int iNewLineIndex)       {           try           {               StringBuilder sbNewSave = new StringBuilder();               sFileName = sFileName.Replace("|", "_");               string sFolder = Directory.GetParent(sFileName).ToString();               if (!System.IO.Directory.Exists(sFolder))               {                   System.IO.Directory.CreateDirectory(sFolder);               }               if (!System.IO.File.Exists(sFileName))               {                   throw new Exception("file not exist");               }               string[] arrLine = sOrigionContent.Trim().Split(Convert.ToChar(Keys.Return));               for (int i = 0; i < iNewLineIndex; i++)               {                   sbNewSave.AppendLine(arrLine[i].Trim('\r').Trim('\n'));               }               sbNewSave.AppendLine(sNewLineContent);               for (int i = iNewLineIndex + 1; i < arrLine.Length; i++)               {                   sbNewSave.AppendLine(arrLine[i].Trim('\r').Trim('\n'));               }               FileStream fsTxtWrite = new FileStream(sFileName, FileMode.Create, FileAccess.Write);               StreamWriter srWrite = new StreamWriter(fsTxtWrite, System.Text.Encoding.UTF8);               //StreamWriter srWrite = new StreamWriter(fsTxtWrite, System.Text.Encoding.Default);               srWrite.Write(sbNewSave.ToString().Trim());               srWrite.Close();               srWrite.Dispose();               fsTxtWrite.Dispose();           }           catch (Exception ex)           {               //MessageBox.Show(ex.Message);               #region ### error info               try               {                   string sFolder = Directory.GetParent(sFileName).ToString();                   string sErrFullName = sFolder + "_err_" + System.DateTime.Now.ToString("yyyyMMddHHmmss") + ".txt";                   if (!System.IO.File.Exists(sErrFullName))                   {                       FileStream fs;                       fs = File.Create(sErrFullName);                       StreamWriter srWrite = new StreamWriter(fs, System.Text.Encoding.UTF8);                       srWrite.Write(sFileName);                       srWrite.Close();                       srWrite.Dispose();                       fs.Close();                   }               }               catch (Exception ex2)               { }               #endregion ###error           }       }