wpf touchdown vs mousedown - wpf

In my application user can use touch and also a mouse.
I am listening for mousedown event:
obj->ImageContainer->MouseDown += ...
But there is a different behaviour when I click either I tap.
In the click handler there is a complex function.
Click works good, the touch tap stucks the application.
I can't understand why.
If I also listen for touchdown event - both of them called.
Anybody have an idea what may be a difference between both?
Thank you

Related

Is it possible that Drag and Drop events in WPF are not firing reliable?

I wonder if D&D events not always firing (DragLeave/DragEnter).
I implemented a D&D feature in my WPF GUI. While dragging some element around I 'dragleave' a GUI element. Normally it fires an appropriate 'DragLeave' event, but not always. I fear, that for some speed reasons sometimes these events get not fired reliable. If that's the case, how can I overcome these issue?
Short Version:
I wrote some sample app to check it myself - and yes - the DragLeave event is not fired reliable.
Long Version:
What I did:
I placed a Label as a draggable object inside a StackPanel. Then I implemented the code for the MouseMove and DragLeave events. An additional TextBlock - added to the StackPanel as well - served as event output. If the DragLeave handler gets called, I changed the Text Property of the TextBlock to 'DragLeave occured'. Afterwards I tested it dragging the Label towards the StackPanel.
What I recognized:
If I was fast enough or pressed the mouse button close to the border of the Label, the DragLeave event was not fired. If I did it slow, everything worked fine as expected.
What I conclude:
I guess, if the mouse leaves the Label before the 'DoDragDrop' thread is initiated, the event is not fired, since the mouse is already outside the Label. So there is a small glitch between starting the D&D and the firing of the first event.
One can see the same behavior in the DragOver/MouseMove handler. The faster you move the mouse, the fewer points (e.GetPosition(...)) you can capture in the event handler.
Problem is, that for the DragLeave that missing event can be critical, since it is only fired once. However, the DragOver event is fired very often during a dragging and a missing event can be balanced by the next DragOver event directly afterwards.

WPF TouchUp Event Strange behaivor

My WPF app functions perfectly, but only when using a mouse. Troubles start when using it on a device with a touch screen..
I have a grid that handles MouseLeftButtonUp and TouchUp events.
Now, I press on the grid, it handles related events, then I press on some other control, that other control catches TouchUp event as expected, then TouchUp event is transformed into MouseLeftButtonUp event, which is also something to expect.
However, the newly fired MouseLeftButtonUp event is fired NOT for the control that I pressed on, but for the above mentioned grid! Why does it behave this way?
Thank you in advance...
This is normal behaviour for all RoutedEvents. From the UIElement.MouseLeftButtonUp event page on MSDN:
Although this routed event seems to follow a bubbling route through an element tree, it actually is a direct routed event that is raised and reraised along the element tree by each UIElement.
MSDN provides far more answers and far quicker than Stack Overflow.

Fire the MouseUp event even when outside control in WPF

I want to be able in my WPF application to detect the MouseUp event from anywhere. That is to say, if the user clicks in the control and holds his click, then releases it outside the Control, I want my MouseUp event to fire.
I have done the MouseDown event, it works, but the MouseUp event isn't fired if released outside the Window.
Add the CaptureMouse method in your MouseButtonDown handler
You can look up here on what it actually does.
Another way is using the windows API's for mouse_event described here:
Simulating Mouse Clicks
I would use the CaptureMouse listed above first but if that doesn't work for you this one should.

previewmousewheel not getting raised when mouse is not on the control in wpf

I have a combobox control's previewmousewheel event been handled. When my mouse is on the control and i move the center wheel of my mouse then this event gets raised. But when my mouse is away from the control and i move the center wheel of my mouse then this event does not get raised.
Can anybody please explain me why is this happening?
If I want to raise an event when my mouse is away from the control then which event should I handle?
This is expected behaviour.
If the mouse cursor is not positioned over the control then no mouse events are routed through it. You wouldn't expect a mouse click event to be routed through it if the cursor was over a different control would you?
If you want this behaviour then I would suggest that you handle the mousewheel event in the page/view and route it from there, be cautious though as user expectation is for mouse and keyboard events to be handled by the in focus item.
In those cases that the user would expect the event to be forwarded to the control you could use Mouse.Capture(someControl) and Mouse.Capture(null) to stop the forwarding.
You should only use this when it makes sense. E.g. when dragging a scrollbar, when you started to drag on the thumb but are not required to stay on top of it as long as you keep the left mouse button down.
When using Mouse.Capture() make sure you always provide a way back from capturing.

WPF MouseMove Event Polling

I've created a WPF application where the title bar and chrome are turned off. I have a border around the entire app, with the idea that it would act like the chrome in some regards. The first thing I'm trying to do is have the mousemove event capture the movement of the mouse when the mouse is clicked, so that the window moves with the mouse. The problem is that if the mouse moves too quickly, it manages to leave the window and therefore the mousemove no longer fires. I've been able to do this with a normal WinForm with no problems regardless of the speed of the mouse. Is there any way to do this more efficiently, or perhaps tune the polling of the mousemove? Perhaps a different container other than border that would perform better?
Try Me.DragMove in the window's left click event handler. It much better than most custom solutions.
When the user clicks you should capture the mouse (see Mouse.Capture). That way, you'll get the mouse events regardless of whether the mouse cursor is over your element or not.

Resources