Set Visibility of Button depending from selected Tab

Question

I have a Button and a TabControl with some Tabs. I want to hide the button, if the second tab is selected. This is my approach, but the button does not disappear if I click on the second tab. What could be wrong?

<Button Content="New" x:Name="NewButton">

    <Button.Style>
        <Style TargetType="Button">
            <Style.Triggers>

                <DataTrigger Binding="{Binding TabMainControl.SelectedIndex}" Value="1">
                    <Setter Property="Visibility" Value="Hidden" />
                </DataTrigger>

            </Style.Triggers>
        </Style>
    </Button.Style>

</Button>



<TabControl TabStripPlacement="Top"  x:Name="TabMainControl">

    <TabItem Header="Name" x:Name="NameTab">...</TabItem>

    <TabItem Header="Code" x:Name="CodeTab">...</TabItem>

    <TabItem Header="Maleware" x:Name="MalewareTab">...</TabItem>

    <TabItem Header="Custom" x:Name="CustomTab">...</TabItem>

</TabControl>

Answer 1

Because you want to bind to the property of another element in your application you should use Binding.ElementName Property and Path like this:

<DataTrigger Binding="{Binding  ElementName=TabMainControl, Path=SelectedIndex}" Value="1">
    <Setter Property="Visibility" Value="Hidden" />
</DataTrigger>