WPF DataTrigger to display and hide grid column XAML

Question

I have an WPF application that contains a grid. The grid is split into 3 columns with the 3rd grid having zero width upon loading.

I have two datagrids in the other two

Answer 1

Using the correct DataTrigger, this is totally possible. First, add the Trigger to the UI element that you want to change... the ColumnDefinition, not the Grid:

<ColumnDefinition>
    <ColumnDefinition.Style>
        <Style TargetType="{x:Type ColumnDefinition}">
            <Setter Property="Width" Value="10" />
            <Style.Triggers>
                <DataTrigger Binding="{Binding OrderSelected.Name}" Value="Mark">
                    <Setter Property="Width" Value="2*" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </ColumnDefinition.Style>
</ColumnDefinition>

Next, don't set the Width on the ColumnDefinition element, but in the Style instead. Otherwise the Width on the ColumnDefinition element will override the value set from the DataTrigger.