I have 2 controls on a form. One numericUpDown (from the Silverlight Toolkit) and a simple Rectangle.
On the MouseLeftButtonDown of the Rectangle I popup a MessageBox with the numericUpDown value.
If I use the arrows to change the value of the numericUpDown, everyting is fine. But if I edit the value manually (with the keyboard) and immediately click on the Rectangle it shows the previous value of the numericUpDown. If I click a sencond time on the rectangle it will show the new value.
The numericUpDown.ValueChanged event is raised after the Rectangle.MouseLeftButtonDown event.
Is that a Silverlight bug? Anybody knows a workaround for that?
(btw I cannot change my Rectangle controls or events)
As workaround I propose you to create your own control like:
public class MyNumericUpDown : NumericUpDown
{
private TextBox _textBox;
public void Sync()
{
ApplyValue(_textBox.Text);
}
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
_textBox = (TextBox)GetTemplateChild("Text");
}
}
Now you can use method Sync to syncronize display text with control Value property. You can call method from XAML declaratively or in code behind. In your case:
private void Rectangle_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
myNumericUpDown.Sync();
MessageBox.Show(myNumericUpDown.Value.ToString());
}
Related
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 am making a map editor for a game which has a user control that has an image. Inside that control I attached the MouseWheel event to it, but I've noticed two issues that I hope to have a better understanding of why it behaves the way it does and how to properly implement it.
For one the event only seems to fire when the mouse is hovering over it instead of when the control is in focus. If possible I would like to switch that and be able to fire the event no matter where the mouse is as long as that control is in focus and the second issue is that checking the delta when the number is positive works fine, but when I get a number back when it's negative I get a value of 0xfffffffd or something in that range. How would I go about differentiating the difference between a positive balue and a negative value if I always get something positive?
Thanks in advance for the help.
If you want to fire MouseWheel event for focused element try:
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
this.MouseWheel += OnMouseWheel;
}
IInputElement focusedElement;
private void OnMouseWheel(object sender, MouseWheelEventArgs e)
{
if (focusedElement is TextBox)
{
var tbx = focusedElement as TextBox;
//do something
}
}
protected override void OnPreviewLostKeyboardFocus(KeyboardFocusChangedEventArgs e)
{
focusedElement = e.NewFocus;
}
}
I have an MVVM setup with a mainwindow that contains a ContentControl.
I set this to a particular viewmodel which then maps to a view.
A view is a usercontrol.
I want to be able to set the default keyboard focus to a default element in the usercontrol(View) when it loads so the application can eventually be driven just by using up, down, left, right and enter.
Some of my failed attempts are setting
FocusManager.FocusedElement="{Binding ElementName=DefaultElement}"
in my content control tag. This sets the logical focus but not the keyboard focus
I'd rather keep the solution in xaml if possable but have tried placing the following in code behind.
Keyboard.Focus(DefaultElement);
This does not work but if I popup a message box first it does. I'm a little confused as to why.
MessageBox.Show(Keyboard.FocusedElement.ToString());
Keyboard.Focus(DefaultElement);
EDIT::::
I just placed this in my onloaded event of my user control. It seems to work but can anyone see any issues that might arrise at this priority level. I.E a circumstance when the action will never run?
Dispatcher.BeginInvoke(
DispatcherPriority.ContextIdle,
new Action(delegate()
{
Keyboard.Focus(DefaultElement);
}));
It seems that this wpf the you have to implement a workaround on a case by case basis. The solution that seemed to work best, most of the time for me was to insert the focus code inside the dispatcher when OnVisible was changed. This sets the focus not only when the View/Usercontrol loads but also if you a changing Views by way of Visibility. If you Hide and then Show a ContentControl that is mapped to your ViewModels then the Loaded event won't fire and you'll be forced to Mouse input, or tabbing (Not so good if you want to navigate your app with a remote control).
VisibilityChanged will always fire however. This is what I ended up with for my listbox.
private void ItemsFlowListBox_IsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if ((bool)e.NewValue == true)
{
Dispatcher.BeginInvoke(
DispatcherPriority.ContextIdle,
new Action(delegate()
{
ItemsFlowListBox.Focus();
ItemsFlowListBox.ScrollIntoView(ItemsFlowListBox.SelectedItem);
}));
}
}
I had the same symptom for a WPF UserControl hosted in a Winforms application. Just wanted to note I was about to try this solution when I found a normal TabIndex in the Winforms app fixed it
Per How to set which control gets the focus on application start
"The one with the minimum tab index automatically gets the focus
(assuming the TabStop property is set to true). Just set the tab
indices appropriately."
It's a tricky one with no easy answer. I'm currently doing this, although I'm not sure I like it:
public MyView()
{
InitializeComponent();
// When DataContext changes hook the txtName.TextChanged event so we can give it initial focus
DataContextChanged +=
(sender, args) =>
{
txtName.TextChanged += OnTxtNameOnTextChanged;
};
}
private void OnTxtNameOnTextChanged(object o, TextChangedEventArgs eventArgs)
{
// Setting focus will select all text in the TextBox due to the global class handler on TextBox
txtName.Focus();
// Now unhook the event handler, since it's no longer required
txtName.TextChanged -= OnTxtNameOnTextChanged;
}
And in case you're wondering what the global class handler does, it's this:
protected override void OnStartup(StartupEventArgs e)
{
...
// Register a global handler for this app-domain to select all text in a textBox when
// the textBox receives keyboard focus.
EventManager.RegisterClassHandler(
typeof (TextBox), UIElement.GotKeyboardFocusEvent,
new RoutedEventHandler((sender, args) => ((TextBox) sender).SelectAll()));
which auto selects TextBox text when receiving keyboard focus.
I am WPF newbie. In a WPF sample code I am looking at, there is a mouse event handler as follows:
namespace Recipe_04_15
{
public class DragCanvasControl : Canvas
{
...
static DragCanvasControl()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(DragCanvasControl),
new FrameworkPropertyMetadata(typeof(DragCanvasControl)));
}
protected override void OnPreviewMouseLeftButtonDown(MouseButtonEventArgs e)
{
...
}
...
What I don't understand is how the OnPreviewMouseLeftButtonDown method is wired to the mouse button down event. The XAML code does not have events specified?
The function is already wired in the UIElement class.
http://msdn.microsoft.com/en-us/library/system.windows.uielement.previewmouseleftbuttondown.aspx
Since you inherit from the canvas you also inherit also from UIElement somewhere deeper.
DragCanvasControl => Canvas => Panel => FrameworkElement => UIElement
By overiding the OnPreviewMouseLeftButtonDown from UIElement you get access to this event.
If it is not in the XAML, it has to be attached in the code-behind. If it is not, the method will not be executed.
Be aware that you are actually looking for the PreviewMouseLeftButtonDown event and not some Click or MouseDown.
I have a usercontrol loaded inside a canvas; this usercontrol on default have visibility collapsed. When a specific textbox of my window is focused the usercontrol become visible.
When usercontrol become visible I want set focus to another textbox inside usercontrol.
I try to do that:
private void UserControl_IsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if (this.Visibility == Visibility.Visible)
{
FocusManager.SetFocusedElement(this, TextBlockInput);
}
}
It seems work but there is a problem: the textbox seems focused but the cursor into textbox don't blink and I can't type chars for input.
I would that after focus the textbox is ready for input. How can I do?
Well, I solve in this way:
private void UserControl_IsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if (this.Visibility == Visibility.Visible)
{
this.Dispatcher.BeginInvoke((Action)delegate
{
Keyboard.Focus(TextBlockInput);
}, DispatcherPriority.Render);
}
}
I think that the problem was tha focus call into IsVisibleChanged event "scope"...right?
try
Keyboard.Focus(TextBlockInput);
see here for more details
Another possible workaround is instead of Visibility property use Opacity. In this case calling Focus() actually sets focus.