Question

我正在尝试设置我的Contextmenu的Datacontext - 但我的代码不起作用。非常相似的代码在另一个位置工作，所以如果有人能解释为什么它不起作用，我将不胜感激。

我的Treeview看起来像这样：注意：它相当长，但我认为嵌套结构是问题的一部分，所以我确实想缩小它。问题出现在ppChart Binding的第二个“级别”上。

    <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>

Answer 1

我认为你的问题恰恰在于这行代码：

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

要解决此问题，您需要将其更改为：

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

但仅此一项不会解决您的问题，因为操作消息的目标将是没有设置其Tag属性的TextBlock。

无论如何，你应该得到类似的代码：

<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>

我最近回复了similar question，您可以查看更多详情。

Answer 2

我找到了一个效果相当不错的解决方案 - 但为什么它的工作原理超出了我的范围：

<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>

注意如何使用Ancestertype树视图。我的赌注是它走向Visual树，直到找到Treeview，它有正确的DataContect。感谢Sniffer，它做得非常好！

Answer 3

如RelativeSource binding from a ToolTip or ContextMenu中所述，无需将标签添加到PlacementTarget。这使它更短，因为不需要向控件和ContextMenu的绑定路径添加标签，例如：

<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>

以及在ViewModel中

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 个答案: