WPF: Canvas mouse events not firing on empty space

Question

I have set mouse events on a Canvas as follows:

<Canvas MouseUp="CanvasUp" MouseDown="CanvasDown" MouseMove="CanvasMove">
...
</Canvas>

But these are active only on the child elements like Image and Rectangle, not on the empty space. How can I solve this?

Rob Fonseca-Ensor · Accepted Answer · 2010-03-24T11:45:28.767

98

A control with no background color set (explicitly or through styles etc) will default to having a background color of null - making it not hit-testable.

If you set the background to "Transparent" (or anything other than null ({x:Null})) then it will be able to pick up the mouse events

edited Mar 24 '10 at 11:45

answered Mar 24 '10 at 11:38

Rob Fonseca-Ensor

15,510
44
57

18

Thanks for the answer, but what a STUPID design decision the WPF team did with that. – cdiggins Oct 04 '11 at 16:09
1

This advice is valuable a golden coin ! I'd rather default Canvas background to Transparent, rather than {x:null} as normally you'd expect event (with appropriate arguments) to fire when you click on canvas empty space. The default x:null behavior should be optionally settable, rather. – Sold Out May 18 '17 at 12:50

score 5 · Answer 2 · edited Jun 30 '14 at 18:57

5

Set the background color. It defaults to null.

Use Background="White" for instance.

edited Jun 30 '14 at 18:57

Pieniadz

653
3
9
22

answered Mar 24 '10 at 11:33

Mark Synowiec

5,385
1
22
18

WPF: Canvas mouse events not firing on empty space

2 Answers2

Linked

Related