C#, windows form, StremWriter, Header line

Question

I am trying to add a header in my running csv file log. This is what I want,

Project Name, Project SN, Project Build < first Row that will never change, unless file was deleted. In that case create a new header line.

After that row, I want the data to be added to next line every time.

Here is what I have so far.

// Write to CSV string path = if (!File.Exists(path)) { File.CreateText(path);

        }

        string projectName = ProjectName_TextBox.Text;
        string projetcBuild = ProjectBuild_TextBox.Text;
        string projectSN = SN_TextBox.Text;
        string header = "Project Name, Project Build, Project SN\n";

        
        using (StreamWriter sw = new StreamWriter(path, true)) // true for appending data to file, false to overwrite in file
        {
           
            sw.WriteLine(header);
            
           
            sw.WriteLine(string.Format(projectName + "," + projetcBuild.ToString() + "," + projectSN.ToString()));
            
            
        }

What this does is it adds the header and data each time a button is clicked. I want the header added to the file only once. Only the data from form will get appended to next line which I think I have. Please help.

Answer 1

File.CreateText returns you a streamwriter; you can use it and also take the opportunity to write the header

string header = "Project Name, Project Build, Project SN\n";

// Write to CSV string path
try{
  StreamWriter sw;

  if (!File.Exists(path)) {
    sw = File.CreateText(path);
    sw.WriteLine(header);
  } else
    sw = File.AppendText(path);

  string projectName = ProjectName_TextBox.Text;
  string projetcBuild = ProjectBuild_TextBox.Text;
  string projectSN = SN_TextBox.Text;
 
  sw.WriteLine(projectName + "," + projetcBuild + "," + projectSN);
            
}
finally{
  sw.Dispose(); 
}

You don't need to call ToString on a string. You don't need to call format on a string with no placeholders. You shouldn't really bother writing your own csv writer; there are so many good libraries out there that does it. This simple implementation will fall down as soon as someone puts a comma in one of the textboxes