WPF: Controlling focus in a custom control - wpf

I am developing a custom control (say BoxControl) which will have many controls in it like a textbox, few buttons etc.
I will have many BoxControls in a row and while navigating via tabs, I want it to behave like when a BoxControl gets focus, it always passes the focus to its textbox and when its textbox loses the focus, the entire BoxControl loses the focu and passes the focus to next BoxControl.
Any ideas how can it be done?

You will need to add an event handler to your BoxControl to handle the GotFocus event and then put the focus on its text box.
You will need also to add an event handler to the LostFocus event of the textbox and then you can raise a custom event on BoxControl so it's controller can know that has to pass the focus to the next BoxControl
Hope it helps.

You can set Focusable property to false by a Setter in your custom control's template. Both on the control and on the various elements inside.

Related

Lostfocus actingas gotfocus for combobox in wpf

I'm using a combobox for which I have Lostfocus event set. But the lostfocus event is fired even when the combobox gets focus i.e gotfocus. Why is it happening so? If that is the default behavior is there any alternative solution for this?
From MSDN UIElement.LostFocus Event :
Because this event uses bubbling routing, the element that loses focus might be a child element instead of the element where the event handler is actually attached. Check the Source in the event data to determine the actual element that gained focus.
You can also use the IsFocused property of your ComboBox check if it has lost focus or not.

How do I find out where the focus is going in my WPF application?

I have a search screen in my WPF application. The screen is implemented as a UserControl in a TabItem of a TabControl. When the user switches to the Search tab, I want the focus to go into one particular field.
So I added a Loaded event handler to the UserControl tag in the Xaml and I called the Focus method of the control I want to have the initial focus in the Loaded event handler. This worked great until I upgraded the Telerik control library I'm using today. Now, when I switch to the Search tab, the focus is NOT in the field I want to have it, but I can't tell what control does have the focus.
The field I want to have focus already has GotFocus & LostFocus event handlers for other reasons. I remembered that in Win Forms, the LostFocus event handler arguments tell you which control is going to get the focus. So I put a breakpoint in my LostFocus handler & discovered that the arguments to the LostFocus event handler in WPF don't include that information.
How can I figure out where the focus is going without putting GotFocus handlers on every control in my UserControl?
Tony
You can try putting your breakpoint on the LostKeyboardFocus Attached Event instead of the LostFocus Event. It uses the KeyboardFocusChangedEventArgs Class which does have properties that show which element had focus and where the focus is going.
private void textBox1_LostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
textBox1.Text = ((FrameworkElement)e.NewFocus).Name ;
}
Try to press Tab Key and see if it helps you find the control in focus.
You can also use Snoop as suggested in this Q/A: Any tips on debugging focus issues in WPF?
For starters, Snoop shows the current focused element and the current
FocusScope in the status bar.
You can get it to show you all the GotFocus and LostFocus events:
1. Run your app.
2. Run Snoop.
3. Choose your app in the dropdown.
4. Click the binoculars ("Snoop") button.
5. On the right pane, click the Events tab.
6. Click to bring down the dropdown.
7. Scroll down to the Keyboard section and check GotKeyboardFocus, LostKeyboardFocus, and optionally the PreviewXXX events.
8. Now do what you need to do to manipulate focus and watch the Snoop window.
Similarly you can track the FocusManager events the same way.

Why does TextBox Leave fire when mouse leaves?

I thought that Leave was supposed to fire when a control loses focus, and MouseLeave was supposed to fire when the mouse is no longer in the control.
I have a TextBox, and if I click in it, then take the mouse out, the Leave event fires. I'm using Leave to validate the entry in the box, like when people hit tab to go to the next control.
Does this mean that a TextBox can't have focus unless the mouse remains in it?
You must have some other code setting focus, because Leave does not fire when the mouse moves out of the control.
You should not be using Leave or LostFocus for validation purposes, instead use TextBox.Validating which is designed specifically for validation scenarios.
This way, if you want to have a Cancel button for example, you can just set its CausesValidation property to false and editor controls Validating events will not fire.
It doesn't matter if the mouse is in it. Property Focus refers to another type of event, when a component is ready to have its value changed, It doesn't matter if you use the keyboard or the mouse. Why don't you validate TextBox value when the Textbox looses Focus?

wpf selecting controls inside a listbox

I have a textbox and some labels inside the data template of bounded listbox.
When I click on any label the whole item is highlighted in blue, but when I click directly on a different textbox the selection does not change.
Is there a way to make the selection of the listbox change even when a textbox is clicked?
thanks
This is what I've exactly asked few days ago, see post: "WPF: Trigger SelectedIndex changed whilst clicking on any control within a ListBoxItem area"
basically there are few solutions, using code behind and XAML, but I've not verified latter approach yet
The reason is because the TextBox handles the click event in order to receive focus. There are a number of ways to handle this, including but not limited to:
stop the TextBox handling mouse events (which prevents the user from focussing it using the mouse)
use an eventhandler when the TextBox gains focus (or PreviewClick or similar), to select the parent ListItem

How to get notified when a window get focus in WPF?

I want to get notified when I click a window in WPF (I use the GotFocus event), but it only triggers when I click on a Combobox in the window. What I want is to get notified when the the window or any of the controls in the window is clicked. Any ideas of how to do this?
The GotFocus event doesn't get fired when the Window gets focus, it's intended to be used with controls only. The Activated event serves this particular purpose.
Use Activated event instead of GotFocus.
You could try the IsKeyboardFocusWithinChanged event. It should trigger when the keyboard focus is taken by an element of the window, or when it is taken by another window

Resources