WPF TextBlock Trigger Question

Kevin Marois

I am trying to hide a text block. When a Checkbox is checked, it should be hidden. When it's unchecked the textblock should be visible. The checkbox is bound to an object called SelectedProcess. If SelectedProcess is null, the textblock should be hidden. Here's my XAML:

        <Style.Triggers>
            <DataTrigger Binding="{Binding SelectedProcess}" Value="Null">
                <Setter Property="UIElement.Visibility" Value="Hidden"/>
            </DataTrigger>
            <DataTrigger Binding="{Binding SelectedProcess.Enabled}" Value="True">
                <Setter Property="UIElement.Visibility" Value="Hidden"/>
            </DataTrigger>
            <DataTrigger Binding="{Binding SelectedProcess.Enabled}" Value="False">
                <Setter Property="UIElement.Visibility" Value="Visible"/>
            </DataTrigger>
        </Style.Triggers>

It works when SelectedProcess is NOT null, but when SelectedProcess IS null, the text is still visible. What am I doing wrong here? Thanks

If it's not broken, fix it until it is

Richard Deeming

Try Value="{x:Null}" instead. http://msdn.microsoft.com/en-us/library/ms743649%28v=vs.110%29.aspx[^]

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

Kevin Marois

That did it. Thank you!

If it's not broken, fix it until it is

BubingaMan

Your issue seems fixed, which is great. However, I wonder why you use datatriggers to accomplish this. Consider doing it through binding instead with the help of a converter. If the visibility of the texblock is always directly related to the checkbox being checked / unchecked, then you could use elementbinding to do so.

The resulting XAML is simpler and achieves the same result.