Question

I’m having a problem here. I have a .txt-file where one line contains “message”, this is the line I wanna change. But I can’t get this code to work, anyone that can help me?
I have this code here that is working for only replacing a string, but I don’t know how to do it so it changes the whole line.

public void t()
{
   string filename = @"F:\test\test.txt";
   StringBuilder result = new StringBuilder();

   if (System.IO.File.Exists(filename))
   {
       using (StreamReader streamReader = new StreamReader(filename))
       {
           String line;
           while ((line = streamReader.ReadLine()) != null)
           {
              string newLine = String.Concat(line, Environment.NewLine);
              newLine = newLine.Replace("message", "HEJHEJ ");
              result.Append(newLine);
           }
       }
   }

   using (FileStream fileStream = new FileStream(filename, FileMode.Open, FileAccess.ReadWrite))
   {
       StreamWriter streamWriter = new StreamWriter(fileStream);
       streamWriter.Write(result);
       streamWriter.Close();
       fileStream.Close();
   }
}

This code is changeing “” to “HEJHEJ”, but I want to whole line in the txt-document to change to “HEJHEJ”, not just only the “message” part

Answer 1

How about changing this:

string newLine = String.Concat(line, Environment.NewLine);
newLine = newLine.Replace("message", "HEJHEJ ");
result.Append(newLine);

to this:

string newLine;
if (line.Contains("message")) {
    newLine = String.Concat("HEJHEJ ", Environment.NewLine);
}
else {
    newLine = String.Concat(line, Environment.NewLine);
}
result.Append(newLine);

There’s a lot cleaner ways to do this, of course.