WPF UserControl Context Menu Visibility Binding

Question

My user control context menu visibility can't bind a dependency property. Any idea?

Here is my WPF code

<UserControl.ContextMenu>
    <ContextMenu Visibility="{Binding ElementName=wellControl, Path=IsInCompactMode, Converter={StaticResource BooleanToVisibilityConverter}}">
    <MenuItem Command="local:GCommands.Edit" />
    <MenuItem Command="local:GCommands.Delete" />
    <MenuItem Command="local:GCommands.ExportFcsFiles" />
    <MenuItem Command="local:GCommands.BatchExportStatistics" />
    <Separator/>
    <MenuItem Command="local:GCommands.SaveAs" Header="Save As..." />
    </ContextMenu>
</UserControl.ContextMenu>

If I set Visibility="Hidden" it will work for me. like this:

<ContextMenu Visibility="Hidden"/>

If use this it won't work

<ContextMenu Visibility="{Binding ElementName=wellControl, Path=IsInCompactMode, Converter={StaticResource BooleanToVisibilityConverter}}">

I'm pretty sure Visibility="{Binding ElementName=wellControl, Path=IsInCompactMode, Converter={StaticResource BooleanToVisibilityConverter}}" has not problem, cuz it works for others.

here is my dependency property

public bool IsInCompactMode
        {
            get {return (bool)GetValue(IsInCompactModeProperty); }
            set {SetValue(IsInCompactModeProperty, value); }
        }
        public static readonly DependencyProperty IsInCompactModeProperty =
            DependencyProperty.Register("IsInCompactMode", typeof(bool), typeof(WellControl), new PropertyMetadata(false));

I tried this way, it seems it still doesn't work, this is really weird!!!

<ContextMenu x:Name="menu" IsOpen="{Binding ElementName=wellControl, Path=IsInCompactMode}"> 

I'm really confuse about it, what's wrong? "Binding ElementName=wellControl, Path=IsInCompactMode" works for other part of the user control, just doesn't work for the weird context menu? it doesn't make sence

Disconcerted

Why not? What happens? What are you trying to do? – Affra

With this amount of information, nobody is going to be able to help you... – Cunha

Sorry guys, I posted this by my cellphone didn't able to add more information. – Disconcerted

Answer 1

1> ContextMenu, Popups, DataGridColumns are not part of visual tree. So the binding using ElementName or RelativeSource wont work just like that.

2> When you want the context menu to not display under particular situation use the triggers to unset the context menu from the visual itself.

      <TextBlock Text="ContextMenu is not shown when DataContext.IsShow is false"}">
            <TextBlock.Style>
                <Style TargetType="{x:Type TextBlock}">
                    <Setter Property="ContextMenu"
                            Value="{StaticResource TextBlockContextMenu}" />
                   <Style.Triggers>
                       <DataTrigger Binding="{Binding IsShow}"
                                    Value="False">
                            <Setter Property="ContextMenu"
                                    Value="{x:Null}" />
                       </DataTrigger>   
                   </Style.Triggers>
                </Style>
            </TextBlock.Style>
      </TextBlock>

3> To attach these items to the visual tree, so that binding works, we use the proxy element method...

Bind datagrid column visibility MVVM

I prefer second step.

Directional

Answer 2

If you are trying to show/hide a context menu you should use the IsOpen property of the ContextMenu, rather than the Visibility property.

Stepaniestepbrother

but this way still doesn't work <ContextMenu x:Name="menu" IsOpen="{Binding ElementName=wellControl, Path=IsInCompactMode}"> – Disconcerted

this does not work. I have tested. – Apportion

Answer 3

You should add the Update Trigger : "UpdateSourceTrigger=PropertyChanged"

<DataGrid.ContextMenu >
    <ContextMenu Visibility="{Binding IsSelectionEnabled, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged,Converter={StaticResource BooleanToVisibilityConverter}}" >
        <ContextMenu.Items>
            <MenuItem Header="Create Layer" Command="{Binding DefineLayerName }" />
        </ContextMenu.Items>
    </ContextMenu>
</DataGrid.ContextMenu>

Ancalin