private void buttonPreview_Click(object sender, EventArgs e) { int width, height; int pagePadding; int lineDistance; int fontSize; if (checkBoxUserDefined.Checked) { width = (int)numericUpDownResolutionWidth.Value; height = (int)numericUpDownResolutionHeight.Value; } else { string resolutionStr = comboBoxPredefinedResolution.SelectedItem as string; int leftBracketIndex = resolutionStr.IndexOf('('); int rightBracketIndex = resolutionStr.IndexOf(')'); string resStr = resolutionStr.Substring(leftBracketIndex + 1, rightBracketIndex - leftBracketIndex - 1); string[] splits = resStr.Split('x'); width = Convert.ToInt32(splits[0]); height = Convert.ToInt32(splits[1]); } pagePadding = (int)numericUpDownPagePadding.Value; lineDistance = (int)numericUpDownLineDistance.Value; fontSize = Convert.ToInt32(comboBoxFontSize.SelectedItem as string); Bitmap img = DrawImage(width, height, pagePadding, lineDistance, fontSize); FormPreview previewer = new FormPreview(img); previewer.ShowDialog(); }