Need to modfy the default tab order of child elements

Question

I have custom control like below. When press tab key focus will move in the order elements arrangement.

Query:

When stackpanel receive tab focus I need to change default tab order toggle button present in stackpanel

Default Tab Order:

DockPanel--Border---StackPanel-->Button1-->button2-->button3

Expected Order

DockPanel--Border---StackPanel-->Button3-->button2-->button1

I need update TabOrder based on its parent. Please suggestion solution modify the tab order based on parent

Note: I need UI as like below arrangements, only i need to modify the tab order for buttons

<DockPanel VerticalAlignment="Center" HorizontalAlignment="Center">
            <Border x:Name="MainBorder">
                <StackPanel>
                    <ToggleButton>Button 1</ToggleButton>
                    <ToggleButton>Button 3</ToggleButton>
                    <ToggleButton>Button 3</ToggleButton>
                </StackPanel>
            </Border>
        </DockPanel>

Answer 1

As mentioned in comments do set the TabIndex property. To step within control do use KeyboardNavigation.TabNavigation attached property.

<DockPanel VerticalAlignment="Center" HorizontalAlignment="Center">
    <Border x:Name="MainBorder">
        <StackPanel KeyboardNavigation.TabNavigation="Local">
            <ToggleButton KeyboardNavigation.TabIndex="3">Button 1</ToggleButton>
            <ToggleButton KeyboardNavigation.TabIndex="2">Button 2</ToggleButton>
            <ToggleButton KeyboardNavigation.TabIndex="1">Button 3</ToggleButton>
        </StackPanel>
    </Border>
</DockPanel>

If you want to modify the tab order at run time I would advice you to create a behavior for it. See Use of Behavior in WPF MVVM? To access attached property from code see Get and set WPF custom attached property from code behind