Im trying to add a UserControl in WPF to a grid, but it doesnt show up when im trying to add via MyGrid.Children.Add(UserControl). So i tried to display the number of childs of my grid and it says 1 after adding the usercontrol. (MyGrid.Children.Clear() doesn't work too. After clearing the grid it says that there are 0 childs left but there are still some UiElements when im compiling my program.)
This problem appears only in 1 function. In an other function (the same class) i can easily add childs to the same grid (myGrid).
My code:
private void AddDateOnClick(object sender, MouseButtonEventArgs e)
{
MyGrid.Children.Clear();
UserControlAddDate ucad = new UserControlAddDate();
MyGrid.Children.Add(ucad);
MessageBox.Show(MyGrid.Children.Count.ToString()); //Only to test if there are some childs
}
When i try to clear this grid in a other function (same class) it clears the grid. Only clearing in this function is a problem. Im not understanding why???
What is this UserControlAddDate? Maybe it is not initialized. That’s why it’s not getting added to the grid..
In that place try to add a textbox to the grid and check if it’s working. If it’s working then it’s the problem with your code.
As mentioned by Ed Plunkett, please try to use templates and databinding. It's the best way to work with WPF.
Try this anyway.
private void AddDateOnClick(object sender, MouseButtonEventArgs e)
{
MyGrid.Children.Clear();
TextBox ucad = new TextBox();
ucad.Text = “TEST”;
MyGrid.Children.Add(ucad);
MessageBox.Show(MyGrid.Children.Count.ToString()); //Only to test if there are some childs
}
Not finding a move event or redraw event in the FrameworkElement class. And Google not helping either. So...
I have a custom ItemsControl populated by an observable collection in the VM. The ItemsControl itself leverages the
<i:Interaction.Behaviors>
<ei:MouseDragElementBehavior ConstrainToParentBounds="True"/>
</i:Interaction.Behaviors>
behavior so the user can drag around the whole assembly.
When the user moves the assembly, I want to be notified by each item as the item is repositioned as a result of the assembly moving. So far I have tried registering for
this.myItem.LayoutUpdated += this.OnSomethingNeedsToUpdate;
but it doesn't seem to fire as I drag the assembly around.
Also
this.myItem.MouseMove += this.OnSomethingNeedsToUpdate;
only works if I mouse into the item which is not good enough. Because I am moving the ItemsControl and then have to go mouse into the item to get the event to fire.
Any ideas? Can I look to some ancestor in the visual tree for help in the form of a OneOfMyDecendantsWasRedrawn event or similar? Again I am trying to be notified when an item moves not be notified when the assembly moves.
I would say your best bet would be to add the MouseDragElementBehavior to your custom ItemsControl in code instead of in the Xaml. Here is how this might look (using a Grid since that is easier to demo):
public class DraggableGrid : Grid
{
public DraggableGrid()
{
Loaded += new RoutedEventHandler(DraggableGrid_Loaded);
}
void DraggableGrid_Loaded(object sender, RoutedEventArgs e)
{
MouseDragElementBehavior dragable = new MouseDragElementBehavior();
Interaction.GetBehaviors(this).Add(dragable);
dragable.Dragging += new MouseEventHandler(dragable_Dragging);
}
void dragable_Dragging(object sender, MouseEventArgs e)
{
// Custom Code Here
}
}
In the section that says Custom Code Here you would loop through you Items and notify them that they are being dragged.
I ended up writting another behavior for the individual items I care about and then wrote a LINQ query to search up the visual tree looking for ancestors with the MouseDragElementBehavior attached to them. That query found the ItemsControl since it was an eventual parent of the Item. I was then able to register for the Dragging event as desried.
Thanks again to Bryant for providing the solution over here.
how do you hide Quick Access Toolbar in a WPF's Ribbon?
For Microsoft Ribbon for WPF, you can hide it by using the VisualTreeHelper. On the Loaded event handler, just resize the row containing the Quick Access Toolbar to 0 :
private void RibbonLoaded(object sender, RoutedEventArgs e)
{
Grid child = VisualTreeHelper.GetChild((DependencyObject)sender, 0) as Grid;
if (child != null)
{
child.RowDefinitions[0].Height = new GridLength(0);
}
}
The Quick Access Toolbar is automatically hidden when the Ribbon control is in a RibbonWindow. When it is not, it seems impossible to hide it. I have already worked hours on this issue and was unable to hide it properly.
But there is one simple workaround: Place the Ribbon control inside of a Panel and give it a negative top margin so it will slide outside of the Panel. Set the Panel's ClipToBounds property to true and the QAT will be hidden.
By the way - there are multiple Ribbon implementations for WPF, even by Microsoft themselves ("Fluent Ribbon" and "Microsoft Ribbon for WPF"), so next time you should mention which one you are talking about.
Or if you want it all in the XAML, this works
<ribbon:Ribbon>
<ribbon:Ribbon.Loaded>CollapseQuickAccessToolbar</ribbon:Ribbon.Loaded>
<x:Code>
private void CollapseQuickAccessToolbar(Object sender, RoutedEventArgs e) {
((Grid)VisualTreeHelper.GetChild((DependencyObject)sender, 0)).RowDefinitions[0].Height = new GridLength(0);
}
</x:Code>
</ribbon:Ribbon>
Here is the solution :
this.ribbonControl1.ToolbarLocation = DevExpress.XtraBars.Ribbon.RibbonQuickAccessToolbarLocation.Hidden;
I know this is an old post, but found an easier solution...
Add this inside the ribbon :-
<ribbon:Ribbon.QuickAccessToolBar>
<ribbon:RibbonQuickAccessToolBar Visibility="Collapsed"/>
</ribbon:Ribbon.QuickAccessToolBar>
Bit late to the party.
<my:Ribbon >
<my:Ribbon.ApplicationMenu >
<my:RibbonApplicationMenu Visibility="Collapsed">
</my:RibbonApplicationMenu>
</my:Ribbon.ApplicationMenu>
This will help to hide the quick bar
The WinForm SplitContainer gets the focus when it's dragged or clicked, while the Splitter does not.
The side-effect of this, is that dragging a SplitContainer bar fires Leave/Validate on other controls, and I need to avoid this.
I already tried setting TabStop and CausesValidation to False, but with no success.
Is there a way to stop the SplitContainer from getting focused? (not a big deal, I can still use the old Splitter, but I lose some nice VS properties...)
Remove the SplitContainer control and replace it manually with Panel and Splitter controls. A little more effort, but a much cleaner outcome.
Try with this code:
//This code will move the focus from the splitContainer to TreeView shortly after moved.
private void splitContainer1_SplitterMoved(object sender, SplitterEventArgs e) {
if(this.splitContainer1.CanFocus) {
this.splitContainer1.ActiveControl = this.treeView1;
}
}
Filini,
The only time that the splitcontainer would have focus is when you are actually moving the splitter. So I would so something like this in your validating and leave events.
private void Button_Leave(object sender, EventArgs e)
{
if(SplitContainer.ContainsFocus)
return;
}
I reproduced your issue and when I added the above it still calls the event of course, but the code execution doesn't occur because the SplitContainer has focus while you are moving the splitter.
Hope that helps.
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.