How to make custom WPF ContentControl that supports drag-and-drop at design time?

Question

I want to create custom WPF control that has a single "child" control inside. Subclassing ContentControl or UserControl works, but has one flaw: these controls don't work in designer mode.

By "don't work" I mean this scenario: suppose I have a Canvas with my custom control in it. I want to put, say, a Button inside my control. I drag it from the toolbox, and it appears inside my control. However, XAML view shows that the new button actually belongs to Canvas, not to my control.

I can place it inside my control by manually editing XAML, but I want the designer to work too.

Interestingly, when I subclass Canvas, Grid or Panel, designer works as expected. However, these controls have many children, which is not what I need.

How can I make a single-child control that works in designer?

Here's a good link, looks like you're going to need s set of calsses with design time functionality http://www.codeproject.com/KB/WPF/XPlorerBar2.aspx — , Mar 04 '11 at 12:59
Sorry, dude, I didn't mean to vote down, how do I revert the it? — , Mar 04 '11 at 13:51
@Dmitry I haven't found an answer by your link, but it is still very helpful for other WPF stuff I have to do, thanks. — Nevermind, Mar 05 '11 at 09:20
@Dmitry: I made an "edit", see if you can revert your downvote now. — BoltClock, Mar 05 '11 at 18:35

score 3 · Accepted Answer · edited Feb 04 '13 at 23:26

3

how about inheriting from Border? that way you could spare yourself the hassle with Designer Extensibility

edited Feb 04 '13 at 23:26

Dave Clemmer

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answered Mar 04 '11 at 19:35

Markus Hütter

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SDP190 · Answer 2 · 2017-05-24T15:51:02.393

I also had a similar question here.

But after digging and digging it seams that the real answer is "NO", there isn't any official way to support dragging controls straight into a custom Content-Control at Design-Time, even implementing 'HitTestCore' as Stephan's answer suggests, does not enable drag&drop at design-time for ContentControl.

For such purposes you should consider inheriting from either Grid or Panel (to allow multiple child controls), or Border (to allow single child).

score 1 · Answer 3 · edited May 23 '17 at 11:48

1

I had the same problem with a content control I am writing and found an easy solution on this StackOverflow thread.

Just implement the HitTestCore method:

protected override System.Windows.Media.HitTestResult HitTestCore(System.Windows.Media.PointHitTestParameters hitTestParameters)
{
    return new PointHitTestResult(this, hitTestParameters.HitPoint);
}

edited May 23 '17 at 11:48

Community

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answered Mar 26 '12 at 06:34

Stephen

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How to make custom WPF ContentControl that supports drag-and-drop at design time?

3 Answers3

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