Code:public void WriteLine(String sFilename, int iLine, string sLines, bool bReplace) { string sContent = ""; string[] delimiterstring = { "\r\n" }; if (File.Exists(sFilename)) { StreamReader myFile = new StreamReader(sFilename, System.Text.Encoding.Default); sContent = myFile.ReadToEnd(); myFile.Close(); } string[] sCols = sContent.Split(delimiterstring, StringSplitOptions.None); if (sCols.Length >= iLine) { if (!bReplace) sCols[iLine - 1] = sLines + "\r\n" + sCols[iLine - 1]; else sCols[iLine - 1] = sLines; sContent = ""; for (int x = 0; x < sCols.Length-1; x++) { sContent += sCols[x] + "\r\n"; } sContent += sCols[sCols.Length-1]; } else { for (int x = 0; x < iLine - sCols.Length; x++) sContent += "\r\n"; sContent += sLines; } StreamWriter mySaveFile = new StreamWriter(sFilename); mySaveFile.Write(sContent); mySaveFile.Close(); } }