WPF TabControl cannot switch tabs when hosting DataGrid

Question

In the default TabControl you can switch tabs using Ctrl+Tab, however if one of the tabs contain DataGrid it all breaks. For example, if I had a simple TabControl containing nothing but TextBoxes:

<TabControl>
    <TabItem Header="Tab1">
        <TextBox/>
    </TabItem>
    <TabItem Header="Tab2">
        <TextBox/>
    </TabItem>
    <TabItem Header="Tab3">
        <TextBox/>
    </TabItem>
</TabControl>

And repeatedly pressed Ctrl+Tab, current Tab would cycle:

Tab1 > Tab2 > Tab3 > Tab1 > ...etc

but if I were to put virtually any DataGrid in one of the middle Tabs, for example:

...    
<TabItem Header="Tab2"> <!--replacing 2nd tab content-->
    <TabItem.Resources>
        <x:Array x:Key="Items" Type="{x:Type Run}">
            <Run Text="Foo"/>
            <Run Text="Bar"/>
            <Run Text="Baz"/>
        </x:Array>
    </TabItem.Resources>
    <DataGrid ItemsSource="{StaticResource Items}"/>
</TabItem>

the Ctrl+Tab would get stuck not being able to ever get past said Tab:

Tab1 > Tab2 > Tab1 > Tab2 > ...etc

How can I fix the issue?

I have tried IsTabStop="False" on the DataGrid and several combinations of KeyBoardNavigation properties, all of those had either no effect or were contraproductive.

Edit(2): the issue seems to appear mainly when the DataGrid is the first focusable child of TabItem, for example content:

<StackPanel>
    <TextBox/>
    <DataGrid ItemsSource="{StaticResource Items}"/>
</StackPanel>

almost works, until user selects the DataGrid. If the grid is selected next Ctrl+Tab goes back to first Tab rather than to the next one.

Not sure what are you talking about, ctrl/tab works fine at my end with a DG in one of the tabs, something else might be causing that! — SamTh3D3v
@SamTheDev I am using empty 4.7.2 project running on Windows 10 machine, with nothing else but XAML code included in the question (pasted as the Window content), what is your setup? — wondra
Same I guess, just pasted your code, three tabs where the third one is the one with the grid, .net 4.7.2 on a win 10 1903. — SamTh3D3v
@SamTheDev try putting the grid in second tab. The cycle stops/restarts at first grid encountered - if the grid is in the last tab you would not be able to tell if it stopped there or the cycle completed as normal. — wondra

SamTh3D3v SamTh3D3v · Accepted Answer · 2019-11-13T13:48:57

Looks like it's a focus problem, when the Datagrid gets the focus it's lost from the TabControl, so set that focus programmatically whenever the ctrl/tab is pressed where the DataGrid is:

 <TabControl  x:Name="TabCtrl">
        <TabItem Header="Tab1" x:Name="Tab1" >
            <TextBox/>
        </TabItem>
        <TabItem Header="Tab3" x:Name="Tab2"  PreviewKeyDown="UIElement_OnPreviewKeyDown">
            <TabItem.Resources>
                <x:Array x:Key="Items" Type="{x:Type Run}">
                    <Run Text="Foo"/>
                    <Run Text="Bar"/>
                    <Run Text="Baz"/>
                </x:Array>
            </TabItem.Resources>
            <DataGrid ItemsSource="{StaticResource Items}" />
        </TabItem>
        <TabItem Header="Tab2"  x:Name="Tab3">
            <TextBox/>
        </TabItem>
    </TabControl>

The handler:

 private void UIElement_OnPreviewKeyDown(object sender, KeyEventArgs e)
    {
        if (e.Key == Key.Tab &&
            (Keyboard.Modifiers & ModifierKeys.Control) == ModifierKeys.Control && sender is TabItem)
        {
            TabCtrl.Focus();
        }
    }

WPF TabControl cannot switch tabs when hosting DataGrid

2 Answers