ruberband in OCC

Hi everyone, the ruberband almost drives me crazy these days. It's very easy to accomplish in MFC with the R2_NOT mode in drawing. But I've got no idea in OCC. I've tried to erase the earlier objects and draw the new ones with erase, clear, remove method in AIS_InteractiveContext.However ,unless I choose to eraseAll, I can never get my work done.

Yeah, does anyone can provide me with a simple sample in ruberband rectangle

I've got my own pseudocode as the followings.
void OnLButtonDown(¡­¡­¡­¡­)
{
save the point for drawing;
}
void OnMouseMove(¡­¡­¡­¡­)
{
if the point Number == 1
{
drawLine(points[0],thisPoint);//thisPoint means the point in MouseMove
myAIScontext->EraseAll();
DisplayMyShape();
}
else if point Number == 2
{
drawRectangle(Points[0],Points[1],thisPoint);//I use Three Points to Draw a //Rectangle
myAIScontext->EraseAll();
DisplayMyShape();
}
else
{
}
}