I have a WPF UserControl that contains a button. I also have a WPF Window that contains a button.
In both the UserControl and the Window I place the following line in XAML:
UIElement.PreviewMouseLeftButtonDown="OnPreviewMouseLeftButtonDown"
and in 'OnPreviewMouseLeftButtonDown' I've place a debug print that displays args.Source.
When I click on the button that is inside the window, I get the button as the EventArgs source. However, when I click the button that inside the UserControl (which is also inside a window, so I could test it, but not the same window) I get the UserControl as the EventArgs source.
I tired to see if there is some decorator around the UserControl (using snoop) but it seems straight forward.
I can't understand what is so special about UserControl in WPF that I don't get the right sender. Can someone please explain to me what am I missing?
While the question is old, I recently ran into a similar problem myself, involving the ContextMenuOpening event. Some amount of searching yielded the source code to UserControl here, which contains the following section:
// Set the EventArgs' source to be this UserControl
internal override void AdjustBranchSource(RoutedEventArgs e)
{
e.Source=this;
}
So, apparently UserControl sets the Source of ANY routed event to itself. I have no idea why it does this, though...
Use e.OriginalSource as mentioned above. If you need to find the button, then you can use VisualTreeHelper.GetParent to find the actual Button control.
I would like to create custom control that will look like standard WPF ComboBox, but instead of instead of having an ItemsPresenter in the popup there will be another custom control. So, I created a new class that derives from System.Windows.Controls.Control, added a IsDropDownOpen property and created a style that is actually a copy of default ComboBox style (main idea is that the Popup.IsOpen and ToggleButton.IsPressed properties are bound to the IsDropDownOpen property of the control).
The problem is that the Popup is not closed when I click outside of the control.
I took a look at the ComboBox class in the Reflector and found out that ComboBox used some logic to update the IsDropDownOpen property when it loses mouse capture. But that code uses some internal classes. Is there any alternative way to determine if the user clicked outside of the control and close the Popup?
UPD: I didn't find the way to attach a file to post, so I uploaded sample project here
There is a custom control that looks like ComboBox, but it has a TreeView in a popup. When you open popup and click outside of the control it closes automatically, but if you open popup, expand 'Item2' and then click outside the popup isn't closed. The question is how to fix this?
There is the Control.LostFocus event, maybe handling that would be sufficient for this.
This code solves the problem.
In the static contructor:
EventManager.RegisterClassHandler(typeof(CustomComboBox), Mouse.LostMouseCaptureEvent, new MouseEventHandler(OnMouseCaptureLost));
Event handler implementation:
private void OnMouseCaptureLost(object sender, MouseEventArgs e)
{
if (Mouse.Captured != _container)
{
if (e.OriginalSource != _container)
{
Mouse.Capture(_container, CaptureMode.SubTree);
e.Handled = true;
}
}
}
I have a ListBox that uses DataTemplateSelector to dynamically decide what
template to use based on the type of the item in the list. I now want to hook
the events that could be fired by controls within the DataTemplate. For example,
if one of the templates has a checkbox in it, I want the application using the
control to be notified when the checkbox is checked. If a different template has
a button within it, I want to be notified when the button is clicked.
Also, since its a ListBox, many of the items could have the same template. So
I will need some kind of RoutedEventArgs so I can walk up from OriginalSource to get
some context information to handle the event.
My solution was to use MouseLeftButtonUp. This works fine for TextBlocks, but it looks like CheckBox and Button controls set handled to true, so the event doesnt bubble up. How can I address these
events so I can assign handlers to them in my calling application?
(Also, Silverlight doesn't actually support DataTemplateSelector, so i followed this example to implement it)
If you are defining the templates in the Xaml for the user control where your event handlers are placed then you should simply be able to assign the event handlers in the Xaml.
However in the specific scenario you outline you can also listen for the MouseLeftButtonUp event via the AddHandler method:-
myListBox.AddHandler(UIElement.MouseLeftButtonUpEvent, myListBox_MouseLeftButtonUp, true);
...
private void myListBox_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
//e.OriginalSource available for your inspection
}
Note by using AddHandler and passing true in the third parameter you will get the event regardless of whether it has been handled.
I have a UserControl which contains a TextBox. When my main window loads I want to set the focus to this textbox so I added Focusable="True" GotFocus="UC_GotFocus" to the UserControls definition and FocusManager.FocusedElement="{Binding ElementName=login}" to my main windows definition. In the UC_GotFocus method i simply call .Focus() on the control i want to focus on but this doesn't work.
All i need to do is have a TextBox in a UserControl receive focus when the application starts.
Any help would be appreciated, thanks.
I recently fixed this problem for a login splash screen that is being displayed via a storyboard when the main window is first loaded.
I believe there were two keys to the fix. One was to make the containing element a focus scope. The other was to handle the Storyboard Completed event for the storyboard that was triggered by the window being loaded.
This storyboard makes the username and password canvas visible and then fades into being 100% opaque. The key is that the username control was not visible until the storyboard ran and therefore that control could not get keyboard focus until it was visible. What threw me off for awhile was that it had "focus" (i.e. focus was true, but as it turns out this was only logical focus) and I did not know that WPF had the concept of both logical and keyboard focus until reading Kent Boogaart's answer and looking at Microsoft's WPF link text
Once I did that the solution for my particular problem was straightforward:
1) Make the containing element a focus scope
<Canvas FocusManager.IsFocusScope="True" Visibility="Collapsed">
<TextBox x:Name="m_uxUsername" AcceptsTab="False" AcceptsReturn="False">
</TextBox>
</Canvas>
2) Attach a Completed Event Handler to the Storyboard
<Storyboard x:Key="Splash Screen" Completed="UserNamePassword_Storyboard_Completed">
...
</Storyboard>
and
3) Set my username TextBox to have the keyboard focus in the storyboard completed event handler.
void UserNamePassword_Storyboard_Completed(object sender, EventArgs e)
{
m_uxUsername.Focus();
}
Note that calling item.Focus() results in the call Keyboard.Focus(this), so you don't need to call this explicitly. See this question about the difference between Keyboard.Focus(item) and item.Focus.
Its stupid but it works:
Pop a thread that waits a while then comes back and sets the focus you want. It even works within the context of an element host.
private void ListView_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
System.Threading.ThreadPool.QueueUserWorkItem(
(a) =>
{
System.Threading.Thread.Sleep(100);
someUiElementThatWantsFocus.Dispatcher.Invoke(
new Action(() =>
{
someUiElementThatWantsFocus.Focus();
}));
}
);
}
Just recently I had a list-box that housed some TextBlocks. I wanted to be able to double click on the text block and have it turn into a TextBox, then focus on it and select all the text so the user could just start typing the new name (Akin to Adobe Layers)
Anyway, I was doing this with an event and it just wasn't working. The magic bullet for me here was making sure that I set the event to handled. I figure it was setting focus, but as soon as the event went down the path it was switching the logical focus.
The moral of the story is, make sure you're marking the event as handled, that might be your issue.
“When setting initial focus at application startup, the element to
receive focus must be connected to a PresentationSource and the
element must have Focusable and IsVisible set to true. The recommended
place to set initial focus is in the Loaded event handler"
(MSDN)
Simply add a "Loaded" event handler in the constructor of your Window (or Control), and in that event handler call the Focus() method on the target control.
public MyWindow() {
InitializeComponent();
this.Loaded += new RoutedEventHandler(MyWindow_Loaded);
}
void MyWindow_Loaded(object sender, RoutedEventArgs e) {
textBox.Focus();
}
since i tried a fuzquat's solution and found it the most generic one, i thought i'd share a different version, since some complained about it looking messy. so here it is:
casted.Dispatcher.BeginInvoke(new Action<UIElement>(x =>
{
x.Focus();
}), DispatcherPriority.ApplicationIdle, casted);
no Thread.Sleep, no ThreadPool. Clean enough i hope.
UPDATE:
Since people seem to like pretty code:
public static class WpfExtensions
{
public static void BeginInvoke<T>(this T element, Action<T> action, DispatcherPriority priority = DispatcherPriority.ApplicationIdle) where T : UIElement
{
element.Dispatcher.BeginInvoke(priority, action);
}
}
now you can call it like this:
child.BeginInvoke(d => d.Focus());
WPF supports two different flavors of focus:
Keyboard focus
Logical focus
The FocusedElement property gets or sets logical focus within a focus scope. I suspect your TextBox does have logical focus, but its containing focus scope is not the active focus scope. Ergo, it does not have keyboard focus.
So the question is, do you have multiple focus scopes in your visual tree?
I found a good series of blog posts on WPF focus.
Part 1: It’s Basically Focus
Part 2: Changing WPF focus in code
Part 3: Shifting focus to the first available element in WPF
They are all good to read, but the 3rd part specifically deals with setting focus to a UI element in a UserControl.
Set your user control to Focusable="True" (XAML)
Handle the GotFocus event on your control and call yourTextBox.Focus()
Handle the Loaded event on your window and call yourControl.Focus()
I have a sample app running with this solution as I type. If this does not work for you, there must be something specific to your app or environment that causes the problem. In your original question, I think the binding is causing the problem.
I hope this helps.
After having a 'WPF Initial Focus Nightmare' and based on some answers on stack, the following proved for me to be the best solution.
First, add your App.xaml OnStartup() the followings:
EventManager.RegisterClassHandler(typeof(Window), Window.LoadedEvent,
new RoutedEventHandler(WindowLoaded));
Then add the 'WindowLoaded' event also in App.xaml :
void WindowLoaded(object sender, RoutedEventArgs e)
{
var window = e.Source as Window;
System.Threading.Thread.Sleep(100);
window.Dispatcher.Invoke(
new Action(() =>
{
window.MoveFocus(new TraversalRequest(FocusNavigationDirection.First));
}));
}
The threading issue must be use as WPF initial focus mostly fails due to some framework race conditions.
I found the following solution best as it is used globally for the whole app.
Hope it helps...
Oran
I converted fuzquat's answer to an extension method. I'm using this instead of Focus() where Focus() did not work.
using System;
using System.Threading;
using System.Windows;
namespace YourProject.Extensions
{
public static class UIElementExtension
{
public static void WaitAndFocus(this UIElement element, int ms = 100)
{
ThreadPool.QueueUserWorkItem(f =>
{
Thread.Sleep(ms);
element.Dispatcher.Invoke(new Action(() =>
{
element.Focus();
}));
});
}
}
}
I've noticed a focus issue specifically related to hosting WPF UserControls within ElementHosts which are contained within a Form that is set as an MDI child via the MdiParent property.
I'm not sure if this is the same issue others are experiencing but you dig into the details by following the link below.
Issue with setting focus within a WPF UserControl hosted within an ElementHost in a WindowsForms child MDI form
I don't like solutions with setting another tab scope for UserControl. In that case, you will have two different carets when navigating by keyboard: on the window and the another - inside user control. My solution is simply to redirect focus from user control to inner child control. Set user control focusable (because by default its false):
<UserControl ..... Focusable="True">
and override focus events handlers in code-behind:
protected override void OnGotFocus(RoutedEventArgs e)
{
base.OnGotFocus(e);
MyTextBox.Focus();
}
protected override void OnGotKeyboardFocus(KeyboardFocusChangedEventArgs e)
{
base.OnGotKeyboardFocus(e);
Keyboard.Focus(MyTextBox);
}
What did the trick for me was the FocusManager.FocusedElement attribute. I first tried to set it on the UserControl, but it didn't work.
So I tried putting it on the UserControl's first child instead:
<UserControl x:Class="WpfApplication3.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Grid FocusManager.FocusedElement="{Binding ElementName=MyTextBox, Mode=OneWay}">
<TextBox x:Name="MyTextBox"/>
</Grid>
... and it worked! :)
I have user control - stack panel with two text boxes.The text boxes were added in contructor, not in the xaml. When i try to focus first text box, nothing happend.
The siggestion with Loaded event fix my problem. Just called control.Focus() in Loaded event and everthing.
Assuming you want to set focus for Username textbox, thus user can type in directly every time it shows up.
In Constructor of your control:
this.Loaded += (sender, e) => Keyboard.Focus(txtUsername);
After trying combinations of the suggestions above, I was able to reliably assign focus to a desired text box on a child UserControl with the following. Basically, give focus to the child control and have the child UserControl give focus to its TextBox. The TextBox's focus statement returned true by itself, however did not yield the desired result until the UserControl was given focus as well. I should also note that the UserControl was unable to request focus for itself and had to be given by the Window.
For brevity I left out registering the Loaded events on the Window and UserControl.
Window
private void OnWindowLoaded(object sender, RoutedEventArgs e)
{
ControlXYZ.Focus();
}
UserControl
private void OnControlLoaded(object sender, RoutedEventArgs e)
{
TextBoxXYZ.Focus();
}
I set it in the PageLoaded() or control loaded, but then I'm calling WCF async service and doing stuff that seems to lose the focus. I have to to set it at the end of all the stuff I do. That's fine and all, but sometimes I make changes to the code and then I forget that I'm also setting the cursor.
I had same problem with setting keyboard focus to canvas in WPF user control.
My solution
In XAML set element to Focusable="True"
In element_mousemove event create simple check:
if(!element.IsKeyBoardFocused)
element.Focus();
In my case it works fine.
When the user clicks on certain part of a window, I add a UserControl to the window's controls. The UserControl has a close button. What can I do in the UserControl's button handler to destroy the UserControl? There seems to be no .net analog to the Win32 DestroyWindow call, and there is no Close() method for a control. So far I have this:
private void sbClose_Click(object sender, EventArgs e)
{
Parent.Controls.Remove(this);
this.Dispose();
}
And, in case the parent needs to destroy the control, what are the steps? This is what I have so far:
Controls.Remove(control);
control.Dispose();
You're working in a managed code environment with garbage collection - there's nothing you can do to force the user control to be destroyed.
All you need to do, all you can do is to remove it from the parent and make sure there are no remaining references.
This will generally be sufficient:
private void sbClose_Click(object sender, EventArgs e)
{
Parent.Controls.Remove(this);
}
The only time you'll need more is if you tie things together with events, as you'll need to deregister those as well.
A control can't destroy itself. In terms of having a parent do it, you are on the right track. You can have the parent or another control call Dispose on it and remove all references to this control. Dereferencing the control this way will allow the GC to clean things up.