Visual Basic 2005: A Developer's Notebook

Improve Redraw Speeds for GDI+

Every control and form in .NET inherits from the base Control class. In .NET 2.0, the Control class sports a new property named DoubleBuffered. If you set this property to True, the form or control will automatically use double-buffering, which dramatically reduces flicker when you add custom drawing code.

Note

Need to turbocharge your GDI+ animations? In . NET 2.0, the Form class can do the double-buffering for you.

How do I do that?

In some applications you need to repaint a window or control frequently. For example, you might refresh a window every 10 milliseconds to create the illusion of a continuous animation. Every time the window is refreshed, you need to erase the current contents and draw the new frame from scratch.

In a simple application, your drawing logic might draw a single shape. In a more complex animation, you could easily end up rendering dozens of different graphical elements at a time. Rendering these elements takes a small but significant amount of time. The problem is that if you paint each graphical element directly on the form, the animation will flicker as the image is repeatedly erased and reconstructed. To avoid this annoying problem, developers commonly use a technique known as double-buffering. With double-buffering, each new frame is fully assembled in memory, and only painted on the form when it's complete.

.NET 2.0 completely saves you the hassle of double-buffering. All you need to do is set the DoubleBuffered property ...