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.NET PowerPacks RectangleShape flickers on form resize

I can do something as simple as:

  1. Create a new .NET form application
  2. Put a single RectangleShape onto the form
  3. add the following into the InitializeComponent method in the designer code

    Me.SetStyle(ControlStyles.AllPaintingInWmPaint Or _
        ControlStyles.UserPaint Or _
        ControlStyles.DoubleBuffer, True)
    Me.UpdateStyles()
    
  4. Run the program
  5. Resize th开发者_运维问答e form
  6. Watch angrily as the rectangle flickers

Is it possible to get rid of this? Or is the ShapeContainer internally flawed and I need to find a different solution?


It's fairly flawed. It uses its own window that's overlaid onto the form with the WS_EX_TRANSPARENT style turned on. That style makes it invisible, but also prevents any kind of double-buffering from working properly. Double-buffering the form has no effect, wrong window.

It is otherwise a rather expensive way to draw shapes. The cheap and flicker-free way is using e.Graphics.FillRectangle() in the form's OnPaint() override or Paint event handler.


I've never used the ShapeContainer but when ever I do custom graphics like that, I create a subclass for a Panel and in the constructor of my subclass I set DoubleBuffered to true.

More specific code example here.

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