Wpf Treeview Contextmenu DataContext

Question

I am trying to set the Datacontext of my Contextmenu - but my Code does not work. Very similar code works at another location, so I would be grateful if somebody could explain why it does not work.

My Treeview looks like this: Beware: it is rather long, but I think the nested structure is part of the problem, so I do want to shrink it. The Problem occurs on the second "level" at the ppChart Binding.

    <TreeView x:Name ="Presentation_SlidesWithIndex" Grid.ColumnSpan="1" HorizontalAlignment="stretch" Height="auto" Margin="0,0,3,0" VerticalAlignment="stretch" Width="auto" Tag="{Binding DataContext, ElementName=LayoutRoot}">
        <TreeView.ItemContainerStyle>
            <!--expand Charts when they contain elements-->
            <Style TargetType="TreeViewItem">
                <Setter Property="IsExpanded" Value="{Binding HasCharts}"/>
            </Style>
        </TreeView.ItemContainerStyle>

        <TreeView.Resources>
            <HierarchicalDataTemplate DataType="{x:Type pp:PPSlide}" ItemsSource="{Binding Charts}">
                <StackPanel x:Name="PPSlideElements" Orientation="Horizontal">
                    <StackPanel.Style>
                        <Style TargetType="{x:Type StackPanel}">
                            <Style.Triggers>
                                <!--Trigger for Slides with Charts-->
                                <DataTrigger Binding="{Binding Path=HasCharts}"  Value="True" >
                                    <Setter Property="Background" Value="LightBlue" />
                                </DataTrigger>
                                <!--Trigger for Slides with NO Charts-->
                                <DataTrigger Binding="{Binding Path=HasCharts}"  Value="False" >
                                    <Setter Property="Opacity" Value=".5" />
                                </DataTrigger>
                            </Style.Triggers>
                        </Style>
                    </StackPanel.Style>
                    <TextBlock FontSize="15">
                        <Run Text="Slide "></Run>
                        <Run Text="{Binding Path=Index}"></Run>
                    </TextBlock>
                    <!--<Image Source="/Images/pptIcon.png" Height="10"></Image>-->
                </StackPanel>
            </HierarchicalDataTemplate>
            <HierarchicalDataTemplate DataType="{x:Type pp:PPChart}" ItemsSource="{Binding ExcelSource}">
                <StackPanel x:Name="PpChartElements" Orientation="Horizontal" AllowDrop="True" cal:Message.Attach="[Event Drop] = [Action DropItem($eventArgs,$view)]" Tag="{Binding DataContext, RelativeSource={RelativeSource AncestorType=UserControl}}">
                    <StackPanel.Style>
                        <Style TargetType="{x:Type StackPanel}">
                            <Style.Triggers>
                                <!--Trigger for Charts with DataSource set-->
                                <DataTrigger Binding="{Binding Path=HasDataSourceSet}"  Value="True" >
                                    <Setter Property="Background" Value="LightGreen" />
                                </DataTrigger>
                                <!--Trigger for Charts with DataSource nit set-->
                                <DataTrigger Binding="{Binding Path=HasDataSourceSet}"  Value="False" >
                                    <Setter Property="Background" Value="Orange" />
                                </DataTrigger>
                            </Style.Triggers>
                        </Style>
                    </StackPanel.Style>
                    <Image Source="{Binding ChartType, Converter={StaticResource PowerPointChartTypeConverter}}" Width="19" Height="19" Margin="2,2,4,2"></Image>
                    <TextBlock  FontSize="14" Text="{Binding Path=ShapeName}" VerticalAlignment="Center">
                        <TextBlock.ContextMenu>
                            <ContextMenu cal:Action.TargetWithoutContext="{Binding Path=PlacementTarget.Tag.AddEntityCommand, RelativeSource={RelativeSource AncestorType=ContextMenu}}">
                                <MenuItem Header="Löse Verknüpfung" cal:Message.Attach="DeleteLink($datacontext)" ToolTip="Löscht einen bestehenden Link zu einer Excel Datei"/>
                            </ContextMenu>
                        </TextBlock.ContextMenu>
                    </TextBlock>
                    <Image Source="{Binding PowerPointWriteStatus, Converter={StaticResource PowerPointWriteStatusConverter}}" Width="19" Height="19" Margin="2,2,4,2" ToolTip="Zeigt erfolg oder misserfolg des Erstellens an"></Image>
                </StackPanel>
            </HierarchicalDataTemplate>
            <HierarchicalDataTemplate DataType="{x:Type pp:PPSourceExcelLink}">
                <StackPanel x:Name="PpSourceExcelLinkStackPanel" Orientation="Vertical">
                    <TextBlock FontSize="14">
                        <Run Text="Datei: "></Run>
                        <Run Text="{Binding Path=ExcelFileName, Mode=OneWay}"></Run>
                    </TextBlock>
                    <TextBlock FontSize="14">
                        <Run Text="Tabelle: "></Run>
                        <Run Text="{Binding Path=SourceTableID}"></Run>
                    </TextBlock>
                </StackPanel>
            </HierarchicalDataTemplate>

        </TreeView.Resources>
    </TreeView>

When you say "my Code does not work", what you exactly mean ? — Nitesh, Jul 26 '13 at 14:49
@Nitesh Caliburn.Micro just throws an exception that it cannot find the method on the target viewmodel, where the methods exists. — Christian Sauer, Jul 31 '13 at 09:01

score 2 · Accepted Answer · edited May 23 '17 at 10:27

2

I think your problem lies exactly in this line of code:

cal:Action.TargetWithoutContext="{Binding Path=PlacementTarget.Tag.AddEntityCommand, RelativeSource={RelativeSource AncestorType=ContextMenu}}"

To fix it you need to change this to:

cal:Action.TargetWithoutContext="{Binding Path=PlacementTarget.Tag.AddEntityCommand, RelativeSource={RelativeSource Self}}"

but this alone won't fix your problem because the target of the action message will be the TextBlock which doesn't have its Tag property set.

Anyway you should end up with code similar to this:

<TextBlock FontSize="14" Text="{Binding Path=ShapeName}" VerticalAlignment="Center" Tag="{Binding DataContext, RelativeSource={RelativeSource Self}}">
    <TextBlock.ContextMenu>
        <ContextMenu cal:Action.TargetWithoutContext="{Binding RelativeSource={RelativeSource Self},Path=PlacementTarget.Tag}">
            <MenuItem Header="Löse Verknüpfung" cal:Message.Attach="DeleteLink($datacontext)" ToolTip="Löscht einen bestehenden Link zu einer Excel Datei" />
        </ContextMenu>
    </TextBlock.ContextMenu>
</TextBlock>

I answered a similar question recently and you can take a look at for more details.

edited May 23 '17 at 10:27

Community

1
1

answered Jul 26 '13 at 15:06

Ibrahim Najjar

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Hello Sniffer, please excuse my very late response - I had some very high priority tasks dropped at me in the meantime. I started with your answer, which I use in another view where the answer works perfectly fine - but in this context, caliburn.micro just throws an exception that it cannot find the DeleteLink method. – Christian Sauer Jul 31 '13 at 09:00
@ChristianSauer make sure the `DeleteLink` method has the right signature, that is it takes an object of type $datacontext as a parameter and make sure it is located on the right object. Since CM is telling you it can't find the method the problem has to be one the above issues. – Ibrahim Najjar Jul 31 '13 at 09:28
The Method has the Signature DeleteLink(object DataContext) - this works in the other View / Viewmodel too. CM does not tell me which ViewModel has the Problem, so I am guessing that it does not find the correct ViewModel. – Christian Sauer Jul 31 '13 at 10:15
@ChristianSauer I guess you will have to put the method on whatever the DataContext of the TextBlock which contains the ContextMenu is. – Ibrahim Najjar Jul 31 '13 at 11:46
@ChristianSauer Thank you for accepting and voting the answer, glad i was able to help. – Ibrahim Najjar Jul 31 '13 at 12:22

score 0 · Answer 2 · answered Jul 31 '13 at 11:45

I found a Solution which works fairly well - but why it works is beyond me:

<TextBlock FontSize="14" Text="{Binding Path=ShapeName}" VerticalAlignment="Center" Tag="{Binding DataContext, RelativeSource={AncestorType=TreeView}}">
    <TextBlock.ContextMenu>
        <ContextMenu cal:Action.TargetWithoutContext="{Binding RelativeSource={RelativeSource Self},Path=PlacementTarget.Tag}">
            <MenuItem Header="Löse Verknüpfung" cal:Message.Attach="DeleteLink($datacontext)" ToolTip="Löscht einen bestehenden Link zu einer Excel Datei" />
        </ContextMenu>
    </TextBlock.ContextMenu>
</TextBlock>

Note how the Ancestertype treeview is used. my bet guess is that it walks the Visual tree until it finds the Treeview, which has the proper DataContect. Thanks to Sniffer, which did a very good job !

score 0 · Answer 3 · answered May 25 '20 at 20:10

As stated in RelativeSource binding from a ToolTip or ContextMenu there is no need to add the tag to the PlacementTarget. This makes it shorter, as there is no need to add a tag to the control and to the binding path of the ContextMenu, e.g.:

<TextBlock FontSize="14" Text="{Binding Path=ShapeName}" VerticalAlignment="Center">
    <TextBlock.ContextMenu>
        <ContextMenu cal:Action.TargetWithoutContext="{Binding Path=PlacementTarget, RelativeSource={RelativeSource Self}}">
            <MenuItem Header="Löse Verknüpfung" cal:Message.Attach="DeleteLink($datacontext)" ToolTip="Löscht einen bestehenden Link zu einer Excel Datei" />
        </ContextMenu>
    </TextBlock.ContextMenu>
</TextBlock>

and in the ViewModel

public void DeleteLink(object parameter)
{
    if (parameter == null)
        return;
    var param = parameter as YourDataContextType;
    if (! (param is YourDataContextType))
        return;

    // your delete handling
}

Wpf Treeview Contextmenu DataContext

3 Answers3