title: Drawing a line in Winforms
body: <p>I am having trouble drawing a line within a group box in a simple windows form.</p>
  
  <p>here is my code:</p>
  
  <pre><code>public partial class Form1 : Form
      {
          public Form1()
          {
              InitializeComponent();                        
          }
  
          protected override void OnPaint(PaintEventArgs e)
          {
              base.OnPaint(e);            
              DrawLShapeLine(groupBox1.CreateGraphics(), 10, 10, 20, 40);
          }
  
          public void DrawLShapeLine(System.Drawing.Graphics g, int intMarginLeft, int intMarginTop, int intWidth, int intHeight)
          {
              Pen myPen = new Pen(Color.Black);
              myPen.Width = 2;
              // Create array of points that define lines to draw.
              int marginleft = intMarginLeft;
              int marginTop = intMarginTop;
              int width = intWidth;
              int height = intHeight;
              int arrowSize = 3;
              Point[] points =
               {
                  new Point(marginleft, marginTop),
                  new Point(marginleft, height + marginTop),
                  new Point(marginleft + width, marginTop + height),
                  // Arrow
                  new Point(marginleft + width - arrowSize, marginTop + height - arrowSize),
                  new Point(marginleft + width - arrowSize, marginTop + height + arrowSize),
                  new Point(marginleft + width, marginTop + height)
               };
  
              g.DrawLines(myPen, points);
          }
      }
  </code></pre>
  
  <p>If I attach the DrawLShapeLine method to a button click event, it draws fine, but it does not draw on load of the form.</p>
  
  <p>Please advice.</p>