I have a UserControl that contains several ComboBoxes and Buttons.
In the window that hosts the UserControl I need to update some properties when the UserControl gets the focus.
My problem is, that every time, when the focus inside the user control changes, that get a GotFocus event in the hosting windows.
Is there some kind of best practice to make sure, that I only get one GotFocused event in the hosting window? I mean, if I step through controls inside the UserControl the focus is always inside the UserControl, so I don't want a GotFocused event.
This is the solution I came up to:
First of all this post was the key for my solution: WPF UserControl detect LostFocus ignoring children .
And Refer to active Window in WPF? .
Using the functions in these posts I registered the LostFocus event in my UserControl.
private void UserControl_LostFocus(object sender, RoutedEventArgs e)
{
var focused_element = FocusManager.GetFocusedElement(Application.Current.Windows.OfType<Window>().FirstOrDefault(x => x.IsActive));
var parent = (focused_element as FrameworkElement).TryFindParent<KeywordSelector>();
if (parent != this) userControlHasFocus=false;
}
And then ...
private void UserControl_GotFocus(object sender, RoutedEventArgs e)
{
if (userControlHasFocus == true) e.Handled = true;
else userControlHasFocus = true;
}
This way I keep track of the focus. userControlHasFocus is false be default. When the GotFocus() happens for the first time it's false and the GotFocus event is not stopped form bubbling up. But userControlHasFocus gets set to true, because now the focus is inside the UserControl.
Whenever the focus moves to another control, LostFocus checks if the new controls parent is the UserControl. If not, it resets the userControlHasFocus to false.
I have a program with a main window in which a user may alter data. The program also has a to-do-dialog, in which the user may see a list of stuff to do - and this dialog has it's own datacontext (connection to database) but needs to show let updated data.
I did not set UpdateSourceTrigger in all my fields in the main window to PropertyChanged (this wouldn't be wanted in all cases anyway because of functionality in the main window).
But I need the main window to do a updatesource on the "active" field in case the user activates the to-do-dialog so that the data may be saved to the database and re-read in the to-do-dialog.
If there were a "Deactivating" event on the window, I could use that to simply set focus to something else (forcing whatever currently focussed control to update it source). But no Deactivating event exists, only Deactivated which happens after the fact. And setting focus in the deactivated main window messes up up the activation of the to-do-dialog. Also, I cannot do this in the to-do-dialogs Actived event. A Activating event would have helped - but that does not exist.
Any good ideas how to force updatesource on my main window before the to-do-dialog gets activated (either by tabbing to it or by clicking it with the mouse)?
This kind of goes off of #AkselK's answer, but I find the keyboard focused control using the Keyboard.FocusedElement property and update the right bindings based on whether its a TextBox, Selector, or ToggleButton. I expected the Keyboard.FocusedElement to tell me the window I was swapping to is what has focus, but it actually does give me the control I was in inside the deactivating window.
void MyWindow_Deactivated(object sender, EventArgs e)
{
if(Keyboard.FocusedElement is TextBox)
{
(Keyboard.FocusedElement as TextBox).GetBindingExpression(TextBox.TextProperty).UpdateSource();
}
else if(Keyboard.FocusedElement is Selector)
{
(Keyboard.FocusedElement as Selector).GetBindingExpression(Selector.SelectedItemProperty).UpdateSource();
//todo: should this also update SelectedValueProperty?
}
else if(Keyboard.FocusedElement is ToggleButton)
{
(Keyboard.FocusedElement as ToggleButton).GetBindingExpression(ToggleButton.IsCheckedProperty).UpdateSource();
}
}
I am unsure if the Selector portion should also update the binding for SelectedValue.
You do not need to set Focus to a different element to update the binding. Instead, you can use the GetBindingExpression method:
valueTextBox.GetBindingExpression(TextBox.TextProperty).UpdateSource();
This might work in the Deactivating event.
My application's building a UI dynamically in which each ItemsControl in the view is a focus scope. The items displayed by each ItemsControl are controls in its focus scope. The user can tab through all of the controls in the view from start to end (i.e. the keyboard navigation mode is Continue). These controls are all bound to data source properties.
What seems to be happening is that when I'm on the last control in the first focus scope and press TAB, the keyboard focus moves to the second focus scope, but the previous control doesn't lose logical focus. So the bound property doesn't get updated.
I can make this problem go away (in theory, at least) by not making each ItemsControl a focus scope. But I didn't decide to implement logical focus capriciously: there are things the application needs to do when each ItemsControl loses logical focus, and if I get rid of the focus scopes it's going to be hard to make that happen.
This seems like a problem that should have a straightforward solution, but nothing in the documentation seems to suggest a way around it. Any ideas?
The problem is that you're trying to make logical focus in-line with keyboard focus which as the documentation shows is really not how it is supposed to be used. Logical focus provides a way to maintain what the previous control that had focus in a given focus scope so you can refocus again on it when you regain keyboard focus.
Looking at your question I think what you really want to do is pick up the event when your item contol, or one of the visual child elements, loses keyboard focus. This can
be achieved using IsKeyboardFocusedWithin property and you can trigger actions based on the associated event.
If you need this to be a routed event, then you'll need a custom control like follows which exposes a routing event for gaining and losing focus.
public partial class FocusManagingControl : UserControl
{
public static readonly RoutedEvent KeyboardLostFocusWithinEvent = EventManager.RegisterRoutedEvent("KeyboardLostFocusWithin",
RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(FocusManagingControl));
public static readonly RoutedEvent KeyboardGotFocusWithinEvent = EventManager.RegisterRoutedEvent("KeyboardGotFocusWithin",
RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(FocusManagingControl));
public event RoutedEventHandler KeyboardLostFocusWithin
{
add { AddHandler(KeyboardLostFocusWithinEvent, value); }
remove { RemoveHandler(KeyboardLostFocusWithinEvent, value); }
}
public event RoutedEventHandler KeyboardGotFocusWithin
{
add { AddHandler(KeyboardGotFocusWithinEvent, value); }
remove { RemoveHandler(KeyboardGotFocusWithinEvent, value); }
}
public FocusManagingControl()
{
this.InitializeComponent();
this.IsKeyboardFocusWithinChanged += FocusManagingControl_IsKeyboardFocusWithinChanged;
}
private void FocusManagingControl_IsKeyboardFocusWithinChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if((bool)e.OldValue && !(bool)e.NewValue)
RaiseEvent(new RoutedEventArgs(KeyboardLostFocusWithinEvent, this));
if(!(bool)e.OldValue && (bool)e.NewValue)
RaiseEvent(new RoutedEventArgs(KeyboardGotFocusWithinEvent, this));
}
}
Which you can use in your XAML with the entry
<local:FocusManagingControl>
<local:FocusManagingControl.Triggers>
<EventTrigger RoutedEvent="local:FocusManagingControl.KeyboardLostFocusWithin">
....
I am trying to make a nice "drag and drop zone" in WPF that is displayed in the adorner layer when something is being dragged into the main application. The problem is that I do not get any events from my adorner, even though it according to documentation should receive all input events since it is in a higher z-order.
To debug my problem I created a really simple example where I have a user control with only a button in it. This user control is displayed in the adorner layer, but I cannot click the button. Why? What have I done wrong?
My adorner class is constructed like this:
public ShellOverlayAdorner(UIElement element, AdornerLayer adornerLayer)
:base(element)
{
_adornerLayer = adornerLayer;
_overlayView = new AdornedElement();
_overlayView.AllowDrop = true;
_adornerLayer.Add(this);
}
and is created in the main window by
private void Window_Loaded(object sender, RoutedEventArgs e)
{
adornerLayer = AdornerLayer.GetAdornerLayer(MyTopGridWithButtonInIt);
ShellOverlayAdorner shell = new ShellOverlayAdorner(MyTopGridWithButtonInIt, adornerLayer);
}
I do not get any events at all from my control, i.e. no mouse clicks, mouse over, button clicks. I cannot even click the button in the adorner layer. What have I done wrong?
I don't know if you already tried that:
If you want the element added to react to events, I think that the element must be bound to the visual tree of the adorner.
The way to do it is to use a VisualCollection, intitialized to the adorner itself, or at least, this way it seems to be working:
VisualCollection visualChildren;
FrameworkElement #object;
public CustomAdorner(UIElement adornedElement) :
base(adornedElement)
{
visualChildren = new VisualCollection(this);
#object = new Button {Content = "prova"};
visualChildren.Add(#object);
}
protected override Visual GetVisualChild(int index)
{
return visualChildren[index];
}
This way the events are correctly routed.
I just had the same issue. Following the advice from MSDN sorted it for me:
Adorners receive input events just
like any other FrameworkElement.
Because an adorner always has a higher
z-order than the element it adorns,
the adorner receives input events
(such as Drop or MouseMove) that may
be intended for the underlying adorned
element. An adorner can listen for
certain input events and pass these on
to the underlying adorned element by
re-raising the event.
To enable pass-through hit testing of
elements under an adorner, set the hit
test IsHitTestVisible property to
false on the adorner.
i.e In the adorner itself, make sure IsHitTestVisible = false
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.