private void button1_Click(object sender, EventArgs e)
        {
            int selstart = textBox1.SelectionStart;

            //get previous newline...
            int linestart = textBox1.Text.LastIndexOf(Environment.NewLine,selstart);
            if (linestart == -1) linestart = 0; else linestart += Environment.NewLine.Length;
            int lineend = textBox1.Text.IndexOf(Environment.NewLine, selstart);
            if(lineend==-1) lineend = textBox1.Text.Length;
            String theline = textBox1.Text.Substring(linestart, lineend - linestart);


            Debug.Print("line was: " + theline);
            //select the line...
            textBox1.SelectionStart = linestart;
            textBox1.SelectionLength = theline.Length;
            textBox1.SelectedText = "#" + theline;
            textBox1.SelectionStart = selstart + 1;


        }