Wpf – Focus on TextBox when UserControl change Visibility

focusinputtextboxuser-controlswpf

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?

Best Answer

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?

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Android – How to stop EditText from gaining focus at Activity startup in Android

Excellent answers from Luc and Mark. However, a good code sample is missing. Adding the tags android:focusableInTouchMode="true" and android:focusable="true" to the parent layout (e.g. LinearLayout or ConstraintLayout) like in the following example, will fix the problem.

<!-- Dummy item to prevent AutoCompleteTextView from receiving focus -->
<LinearLayout
    android:focusable="true" 
    android:focusableInTouchMode="true"
    android:layout_width="0px" 
    android:layout_height="0px"/>

<!-- :nextFocusUp and :nextFocusLeft have been set to the id of this component
to prevent the dummy from receiving focus again -->
<AutoCompleteTextView android:id="@+id/autotext"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    android:nextFocusUp="@id/autotext" 
    android:nextFocusLeft="@id/autotext"/>

Wpf – Set the caret/cursor position to the end of the string value WPF textbox

You can set the caret position using CaretIndex property of a TextBox. Please bear in mind that this is not a DependencyProperty. Nevertheless, you may still set it in XAML like this:

<TextBox Text="123" CaretIndex="{x:Static System:Int32.MaxValue}" />

Please remember to set CaretIndex after Text property or else it will not work. Thus it probably won't work if you bind to Text like in your example. In that case, simply use code-behind like this.

NumberOfDigits.CaretIndex = NumberOfDigits.Text.Length;

Best Answer

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