I have a little problem with winforms and mousewheel events.
I have a custom user control representing a slider. Now, I have a couple groups of sliders in which each group is wrapped inside a panel. All the groups are then wrapped in another panel (which has AutoScroll set to true) and this is wrapped in a form. The slider logic is implemented such that the mousewheel can be used to change its value. For this, the slider user control gets focus when the mouse is over the slider. However, when I scroll, also the AutoScroll parent panel scrolls with it.
I've already lost a lot of time on this issue. Anybody knows what is happening here and how I can solve it? I thought the event was bubbling to the parent panel but I don't find a Handled property on the event when handling it in the Slider control (as is possible with WPF).
many thanks
We implemented the Slider as a complete custom user control (inheriting the UserControl class) with own look-and-feel.
You might have noticed that a UserControl doesn't show the MouseWheel event in the Properties window. Hint of trouble there. The WM_MOUSEWHEEL message bubbles. If the control that has the focus doesn't handle it then Windows passes it on to its Parent. Repeatedly, until it finds a parent window that wants to handle it. The Panel in your case.
You'll need to invoke a bit of black magic in your slider control. The actual event args object that get passed to the MouseWheel event is not of the MouseEventArgs type as the event signature suggests, it is HandledMouseEventArgs. Which lets you stop the bubbling. Like this:
protected override void OnMouseWheel(MouseEventArgs e) {
base.OnMouseWheel(e);
// do the slider scrolling
//..
((HandledMouseEventArgs)e).Handled = true;
}
If you are creating event dynamically like
object.event += new EventHandler<EventArgs>(eventfunction);
try un-registering the event after the eventfunction is called like this
object.event -= new EventHandler<EventArgs>(eventfunction);
Related
I am developing a custom user control in WPF and trying to receive all touch events OUTSIDE of my control (so I can implement "cancel touches", where the user cancels an action by tapping somewhere else). Is there any good way to do this? Obviously, if I use TouchDown or other events I will only get notified of touches inside my control.
I tried receiving PreviewTouchDown events from Application.Current.MainWindow, but besides the fact it feels kind of dirty it also doesn't work that well - as soon as I capture those events, the SurfaceListBox inside my custom control stops working (it does not recognize touches anymore).
Is there a good way to solve this? Receiving simply ALL touch events would be sufficient as well, I can then check if they are inside my control.
In WPF, events travel the tree of elements. Events starting with "Preview" are the ones that travel up to bottom, meaning from the parent to the elements it contains. In your case, TouchDown event will travel from the control in which it originates and then it will bubble up towards the parents. PreviewTouchDown will travel in the opposite direction: from the parent towards the control.
Your idea of handling PreviewTouchDown event in the Application.Current.MainWindow is a good one and should handle all PreviewTouchDown events, if this is what you want. But in your case, if you want to check if the event originates in your custom control, you should catch all the TouchDown events in your MainWindow and check their Source property, like this:
private void CommonClickHandler(object sender, RoutedEventArgs e)
{
FrameworkElement feSource = e.Source as FrameworkElement;
if(feSource.Name == "MyCustomControlName")
{
//cancel whatever you want to cancel
e.Handled=true;
}
}
Do not catch the PreviewTouchDown event as this one will first pop in the MainWindow and just later will go all the way to your control.
This msdn link should give you more information: http://msdn.microsoft.com/en-us/library/ms742806.aspx
I added a Panel inside a UserControl i design time.
Then, I added this control to a form.
I want to show a focus dashed border when the control has the focus.
Unfortunately, the Enter event from the panel never fires. I only get a fire when I click on the user control itself.
To extend this question. How can I forward events from controls inside a user control to the base user control? A comment from Hans Passant in this question says that by default events are forwarded to their direct parent. I didn't change any of the control's properties. What am I doing wrong? Is there an obvious property I need to change on each control i order to force it to forward unhandled events?
I am using DevExpress controls but this behavior is same in windows WinForms controls.
edit: I understand that panel might not be able to get focus. If this is true, how do I forward each mouse event to the parent control?
Based on your comment, from inside your UserControl, handle the panel's MouseDown event and set the focus to the parent control:
public UserControl1() {
InitializeComponent();
panel1.MouseDown += new MouseEventHandler(panel1_MouseDown);
}
void panel1_MouseDown(object sender, MouseEventArgs e) {
if (!this.Focused)
this.Focus();
}
Use panel1.Select() on MouseClick event of the panel and you will be able to trigger panel1.Enter and panel1.Leave
I have a ScrollViewer that contains a large image. I want the user to be able to hold the mouse down and drag the image to move it side to side, and I'm trying to implement this using a Behavior. The problem is that the mouse down event doesn't seem to be able to fire on the ScrollViewer when a user presses down on the mouse button. With a code behind, I would handle that event on the image, but with a behavior that is only attached to one control I don't know how to approach this issue.
What approach should I use to create a System.Windows.Interactivity.Behavior that attaches to both objects?
The MouseLeftButtonDown event is raised just fine on the ScrollViewer. The problem is that the ScrollViewer is handling the event itself (e.Handled = true). And since it is already handled your behavior do not receive it.
Depending on what you are doing you might be able to just use the PreviewMouseLeftButtonDown event instead. This way it doesn't matter if the ScrollViewer will handle it since the Behavior is receiving it first.
You could also try to use the Drag&Drop events directly. But I'm not sure if that will work.
You don't need to attach to an element to be able to add an event handler to it. If your AssociatedObject is a ScrollViewer then you might be able to get a reference to the image like this:
var image = AssociatedObject.Content as Image;
and then you can add a mouse event handler:
image.MouseLeftButtonDown += (s, e) => Debug.WriteLine("Clicked!");
So the object you are attached to, your associated object, is your "home base", but you can work with any object you can get your hands on up to and including using VisualTreeHelper to walk the visual tree.
I have a MyButton class that inherits from Button. On this class I have placed several other controls (Labels, Progessbar). The problem with this is that the controls on the Button make it impossible to fire the Button.Click or Button.MouseHover event. How can I achieve it that the controls on the Button are only displayed but are "event transparent": A click/hover on the label and progessbar is the same as if I clicked/hover directly on the Button (including sender and everything). Something like "inheriting the events from the parent".
class MyButton : Button
{
Label foo = new Label();
ProgressBar bar = new ProgessBar();
}
You should derive from UserControl then have the button as a child control, and bubble up the button child's on click event.
This link is probably more than what you need, but it's a good starting point.
UPDATE
As pointed out, you may not be using ASP.NET. So here is another post that talks about different custom user controls, specifically what you're after is a Composite Control. This is for Windows Forms.
Write Click event handlers for the label and PB, have them call PerformClick().
Making controls transparent to the mouse is possible but is ugly to do. You'd have to override WndProc() to catch WM_NCHITTEST and return HTTRANSPARENT. The all-around better solution is to not use controls. A Label is just TextRenderer.DrawText() in the button's Paint event. ProgressBar isn't hard either, e.Graphics.FillRectangle().
Having the child controls be real controls in front of the button (either in a class inheriting from Button or from UserControl) may make it hard to get button-specific events working properly, as you have found. (Edit: Although it's hard, it's not impossible -- see Hans Passant's answer)
As a workaround, instead of using child controls, you could custom-paint them onto the button surface, since you don't need most of the functionality of the controls (events, focusing, etc.), just their display.
You can do the additional painting in the OnPaint method of your class. Something like:
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
e.Graphics.DrawString("My fake label", Font,
SystemBrushes.ControlText, new Point(10, 10))
// draw progressbar
}
To update the display, you would need to trigger a repaint of the Button using Invalidate().
Take a look at Custom Bitmap Button Using C# on CodeProject for a more complete example.
This answer was here a moment ago, but got deleted:
Can you inherit from UserControl instead? This will allow you to place other controls on the control surface, including your button and subscribe to their events.
If you're using WPF, I guess what you're looking for would be something called Bubbled Events. It's a feature in WPF by which events are bubbled from a control to its parent (in your case, it would be from your ProgressBar and Label to your button). I found this article on the matter which I think would be of help to you.
Hope this helps :)
I'm making a calendar From in C# using WinForms.
I've put it together using a two-dimensional array of Panels, and inside them I have a List<> of custom controls which represent appointments.
The user needs to be able to drag appointment controls from one Panel to another (from day to day).
The custom control has a MouseDown and MouseUp event, which passes a message up from the control to the Parent.Parent (custom control -> day panel -> calendar form) and calls public methods StartDragging() and StopDragging() respectively.
Inside these methods, I make a clone of the custom control and add it to the Form, and store it in a global variable in the form which is called DraggedControl.
The Form has an event handler for MouseMove which goes like this:
void Calendar_MouseMove(object sender, MouseEventArgs e)
{
if (DraggedControl == null)
return;
DraggedControl.Location = PointToClient(MousePosition);
Refresh();
}
There are two problems, however:
First of all, the custom control is under everything else. I can see it being added and removed on MouseDown and MouseUp, but it is being added at 0,0 under the panels and day Labels.
Secondly, it does not appear to be moving with the MouseMove at all. I have a feeling this might be because I am moving the mouse with the button pressed, and this would represent a drag action rather than a basic MouseMove.
If I remove the MouseUp code, the control does drag with the mouse, however as soon as the mouse enters the panels (which the control is, sadly, underneath), the drag action stops.
What would you suggest I do?
I suspect there is probably a better way to do what I am trying to do.
custom control is under everything
else
bring it on top:
DraggedControl.BringToFront();
it does not appear to be moving with
the MouseMove at all
Control, which handled MouseDown event, captures mouse input and receives all following MouseMove events until it releases mouse input on MouseUp event, that's why Calendar_MouseMove() is not called. Handle MouseMove event for the same control, which generated MouseDown event.