How to record a custom event upon button click?

Hi, maybe this is what you want:

...
            int remainder;
            string result = string.Empty;
            while (decimalNumber > 0)
            {
                remainder = decimalNumber % 2;
                decimalNumber /= 2;
                result = remainder.ToString() + result;
            }
            MessageBox.Show("Conversion was sucessful. Your binary code is: " + result, "Conversion Sucessful");
            using (SaveFileDialog dlg = new SaveFileDialog())
            {
                dlg.Filter = "txt file|*.txt";
                if (dlg.ShowDialog() == System.Windows.Forms.DialogResult.OK)
                {
                    using (System.IO.StreamWriter sw = new System.IO.StreamWriter(dlg.FileName))
                    {
                        sw.Write(result);
                    }
                }
            }

Or you can use File.WriteAllText:

...
            int remainder;
            string result = string.Empty;
            while (decimalNumber > 0)
            {
                remainder = decimalNumber % 2;
                decimalNumber /= 2;
                result = remainder.ToString() + result;
            }
            MessageBox.Show("Conversion was sucessful. Your binary code is: " + result, "Conversion Sucessful");
            using (SaveFileDialog dlg = new SaveFileDialog())
            {
                dlg.Filter = "txt file|*.txt";
                if (dlg.ShowDialog() == System.Windows.Forms.DialogResult.OK)
                {                   
                    System.IO.File.WriteAllText(dlg.FileName, result);
                }
            }