Controlling navigation on tab button press based on conditions in WPF C#

Question

I have few drop downs in my screen and I want to control the navigation from one drop down to another on tab button press if nothing is selected in the drop downs. How I can achieve this.I'm using mvvm pattern wpf application.

Answer 1

If I understand correctly, basically you want a combobox to be a tab stop ONLY if there's nothing selected (perhaps to facilitate form filling?). Would a style like this work?

    <Style TargetType="ComboBox">
        <Setter Property="IsTabStop" Value="False"></Setter>
        <Style.Triggers>
            <Trigger Property="SelectedItem" Value="{x:Null}">
                <Setter Property="IsTabStop" Value="True"/>
            </Trigger>
        </Style.Triggers>
    </Style>