Question

I am trying to download some text output from the screen as a text file. Following is the code. It’s working on some pages and not working at all on other pages. Can anyone please suggest what’s wrong here?

protected void Button18_Click(object sender, EventArgs e){
    Response.Clear();
    Response.Buffer = true;
    Response.ContentType = "text/plain";
    Response.AppendHeader("content-disposition", "attachment;filename=output.txt");

    StringBuilder sb = new StringBuilder();
    string output = "Output";
    sb.Append(output);
    sb.Append("\r\n");
    Response.Write(sb.ToString());
}

Answer 1

As already mentioned by Joshua, you need to write the text to the output stream (using Response object). Also, don’t forget to invoke Response.End() after that.

protected void Button18_Click(object sender, EventArgs e)
{
    StringBuilder sb = new StringBuilder();
    string output = "Output";
    sb.Append(output);
    sb.Append("\r\n");
    
    string text = sb.ToString();
    
    Response.Clear();
    Response.ClearHeaders();

    Response.AppendHeader("Content-Length", text.Length.ToString());
    Response.ContentType = "text/plain";
    Response.AppendHeader("Content-Disposition", "attachment;filename=\"output.txt\"");

    Response.Write(text);
    Response.End();
}

Edit 1: added more details

Edit 2: I was reading other SO posts where users were recommending to put quotes around the filename:

Response.AppendHeader("content-disposition", "attachment;filename=\"output.txt\"");

Source:
https://stackoverflow.com/a/12001019/558486