C#

<br />
public class MyControl : Control<br />
{<br />
 ...<br />
 //override Control.Visible,as this property doesn't take "false" value at design time<br />
 private bool visible = true;<br />
<br />
 //this value is insepcted by the form..so it knows if it should redraw the control<br />
 public bool isValid;<br />
<br />
...<br />
public Image GetImage() //returns control's present image(it can be changed)<br />
...<br />
protected override void OnPaintBackground(PaintEventArgs pevent)<br />
{<br />
 //don't do nothing,as the form takes care of all the painting<br />
}<br />
<br />
protected override void OnPaint(PaintEventArgs e)<br />
{<br />
 //HERE i don't know what to do<br />
 //I think i need this:<br />
 isVisible = false; //let the form now that the control was invalidated<br />
 Parent.Invalidate() //tell the parent that the control is invalidated..so redraw it<br />
 //use winapi to validate the window..so it doesn't keep sending WM_PAINT<br />
 ValidateRect(this.Handlde) <br />
}<br />

<br />
public partial class TestForm : Form<br />
{<br />
...<br />
 protected override void OnPaint(PaintEventArgs e)<br />
 {     <br />
  for (int i = Controls.Count - 1; i >= 0; i--)<br />
  {<br />
   if (Controls[i] is MyControl)<br />
   {<br />
    if (!((MyControl)Controls[i]).IsValid && ((MyControl)Controls[i]).GetImage() != null)<br />
    {<br />
      grafx.Graphics.DrawImageUnscaledAndClipped<br />
       (((MyControl)Controls[i]).GetImage(),<br />
       ((MyControl)Controls[i]).ImageRect);<br />
     ((MyControl)Controls[i]).IsValid = true; //validate it<br />
    }<br />
   }<br />
  }<br />
  grafx.Render(e.Graphics); // grafs is the BufferedGraphics<br />
}<br />