Unable to programmatically focus

[ITC]

Hi,
I'm using 2017.3.913.45 and I've been trying to focus a NumericUpDown-Control when the user changes the current Tab of a RadTabControl.

So I've got a RadTabControl:

<telerik:RadTabControl ... SelectionChanged="TabControl_SelectionChanged" ...>

    ..

    <telerik:RadTabItem Name="MyTab">

        ..

        <telerik:RadNumericUpDown Name="MyNumericUpDown" ..></telerik:RadNumericUpDown>
         ..


    </telerik:RadTabItem>

    ..

</telerik:RadTabControl>

 

And a TabControl_SelectionChanged Method:

private void TabControl_SelectionChanged(object sender, RadSelectionChangedEventArgs e)
{
    try
    {
        if(e.AddedItems[0] == MyTab)
        {
           MyNumericUpDown.Focus();
            Keyboard.Focus(MyNumericUpDown);
        }
    }
    catch
    {
        System.Diagnostics.Debugger.Break();
    }
}

 

I initially only tried with MyNumericUpDown.Focus() which did not work, a colleague asked me to add the Keyboard.Focus(MyNumericUpDown) call, but that also does not work.

What's the workflow here?

[Dinko | Tech Support Engineer]

Hi Rolf,

Thank you for your interest in RadNumericUpDown control.

Let me first elaborate on the default focus behavior of the RadTabItem content. Internally in code, we are setting focus to the first element placed in the content of the RadTabItem. Currently, this logic cannot be overridden. 

As a workaround, you can use a dispatcher to focus the desired control. You also need to set the DispatcherPriority to ApplicationIdle. Check the following code snippet.

this.Dispatcher.BeginInvoke(new Action(() =>
{
    MyNumericUpDown.Focus();

}),DispatcherPriority.ApplicationIdle);

Regards,
Dinko
Progress Telerik

[ITC]

Hi Dinko,

thanks for the reply, I replaced the code and it seems to work. However, strangely the two lines I had there first worked the last two days without me even realizing it. Seems arbitrary.

Thanks!