What is WPF equivalent of Windows Forms Region.Xor in Paint event?

Question

I'm trying to move this WinForms code to WPF, but there is no Paint event.

private void OnPaint(object sender, PaintEventArgs e)
{
    var region = new Region(new Rectangle(0, 0, this.Width, this.Height));
    var rectangle = new Rectangle(0, 0, 50, 50);
    region.Xor(rectangle);
    e.Graphics.FillRegion(Brushes.Black, region);
}

Welcome to SO! I have edited your code so that it displays correctly. — Brian, Sep 06 '13 at 23:28
Please read [Rachel's Excellent Explanation](http://stackoverflow.com/a/15684569/643085) of what's required when upgrading from winforms to WPF. — Federico Berasategui, Sep 07 '13 at 03:18

score 1 · Answer 1 · answered Sep 06 '13 at 23:27

1

WPF doesn't work like WinForms in terms of graphics. You can't actually draw shapes, you have to place them into your content.

Geometry should serve as a good replacement for Region. You can use Geometry.Combine and specify GeometryCombineMode.Xor to replicate your drawing code.

RectangleGeometry is how you make rectangles. There are similar classes for other shapes.

To actually display the Geometry, put it in a Path, which can be used as a control's content.

answered Sep 06 '13 at 23:27

Kendall Frey

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You can actually draw shapes (as well as Geometry objects) using the `OnRender` override. That's how `Path` does it. The important thing to remember is that WPF uses retained mode graphics (opposed to immediate mode of GDI). – Eli Arbel Oct 03 '13 at 13:11

What is WPF equivalent of Windows Forms Region.Xor in Paint event?

1 Answers1

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