How to replace a line in a text file?

How to replace a line in a text file?

• maxal

  You'll have to re-write the whole file. Something like this:

  StreamReader r = new StreamReader(filenameIn);

  StreamWriter w = new StreamWriter(filenameOut);

  try {

  string line = string.Empty;

  while ((line = r.ReadLine()) != null) {

  if (line.Contains("some string")) {

  line = "some other string";

  }

  w.WriteLine(line);

  }

  }

  catch (Exception ex) {

  // handle exception

  }

  finally {

  r.Close();

  w.Close();

  }

  
  

• dreameR.78

  That'll work fine, but it's better to use "using" to automatically dispose of object so you don't need to manually include a "finally" block:
  
  

  using (StreamReader r = new StreamReader(filenameIn)) using (StreamWriter w = new StreamWriter(filenameOut)) { try { for (;;) { line = r.ReadLine(); if (line == null) break; if (line.Contains("some string")) { line = "some other string"; } w.WriteLine(line); } } catch (Exception ex) { // handle exception } }

  
  
  
  
• How to replace a line in a text file?