Question

I’m trying to create .txt files with my program and saving the contents of a richtextbox in them (or simply editing existing files, but this already works). The problem is that when I save try saving the file, it creates the file but without the .txt extension. I’ve tried a couple of things, including the following two, but both create a file without extension. How can I fix this?

            SaveFileDialog op = new SaveFileDialog();
            op.Title = "Save";
            op.Filter = "Text Document(*.txt)|*txt";
            //op.DefaultExt = "txt";
            //op.AddExtension = true;

            if (op.ShowDialog() == DialogResult.OK)
            {
                using (Stream s = File.Open(op.FileName, FileMode.CreateNew))
                using (StreamWriter sw = new StreamWriter(s))
                {
                    sw.Write(richTextBox1.Text);
                }
            }

And:

   SaveFileDialog op = new SaveFileDialog();
   op.Title = "Save";
   op.Filter = "Text Document(*.txt)|*txt";
   if (op.ShowDialog() == DialogResult.OK)
   {
       richTextBox1.SaveFile(op.FileName, RichTextBoxStreamType.PlainText);
       filename = op.FileName;
       this.Text = op.FileName;
   }

Answer 1

You need to add a dot before the extension here:

op.Filter = "Text Document(*.txt)|*txt";

So it becomes this:

op.Filter = "Text Document(*.txt)|*.txt";