What does Binding="{Binding (0)}" mean?
controltemplate, datatrigger, expression-blend, ribbon-control, wpf
Solution
It looks like a bug. As far as I know, in WPF can not be `Binding` of this type. Below is a list of deficiencies, please pay attention to the first paragraph, quoted from `connect.microsoft.com` (archive):
I'm trying to style the ribbon control (System.Windows.Controls.Ribbon) and I keep running into problems.
If I use Blend or another tool to copy the default template of the Ribbon, the RibbonGroup, the RibbonTab, etc. these templates have errors. There are Bindings like `{Binding (0)}`.
I cannot change the height of the ribbon control.
It's not possible to change the template of the RibbonGroup, to change the appearance of the separator and to place the header in the top left corner of the group.
It's not possible to add a label to the ApplicationMenuButton. Furthermore this button has a fixed width.
I can't manage to remove the borders at the bottom of the ribbon control.
As I understand it, there is no hotfix.
Problem
I found this: ``` <DataTrigger Value="True" Binding="{Binding (0)}"> ``` triggers in `RibbonMenuButton` template. What does it mean? I've tried to google, but found nothing. UPD more code: ``` <ControlTemplate x:Key="RibbonMenuButtonControlTemplate1" TargetType="{x:Type RibbonMenuButton}"> ... <DataTrigger Binding="{Binding (0)}" Value="True"> <Setter Property="TextElement.Foreground" TargetName="MainGrid" Value="{DynamicResource {x:Static SystemColors.MenuTextBrushKey}}"/> <Setter Property="PathFill" TargetName="TwoLineText" Value="{DynamicResource {x:Static SystemColors.MenuTextBrushKey}}"/> <Setter Property="CornerRadius" TargetName="OuterBorder" Value="0"/> <Setter Property="Background" TargetName="OuterBorder" Value="Transparent"/> <Setter Property="BorderBrush" TargetName="OuterBorder" Value="Transparent"/> </DataTrigger> ... ``` This code created in Blend after "edit template" button pressed on `RibbonMenuButton` control.