ItemContainerStyle内的Caliburn Micro Action-未找到方法的目标 [英] Caliburn Micro Action inside ItemContainerStyle - No target found for method

问题描述

我正在使用Caliburn Micro作为MVVM框架的WPF项目，在过去的一周中我很幸运地找到了StackOverflow上任何问题的所有解决方案，但是现在我面临着一个更大的问题

I'm working on a WPF project using Caliburn Micro as a framework for MVVM, and during the last week I've been lucky enough to find every solution to any problem on StackOverflow, but now I'm facing a bigger issue that I can't solve by myself.

我有一个包含TreeView的View；在以下情况下，树视图的每个项目都应调用一个方法：

I have a View containing a TreeView; each item of the treeview should invoke a method when:

• 双击[工作]


• 单击上下文菜单项[不起作用]

这是TreeView：

This is the TreeView:

<TreeView x:Name="projectTreeView"
              Visibility="{Binding ExplorerVisibility, Converter={StaticResource visibilityConverter}}">
        <TreeViewItem Header="{Binding ProjectName}" IsExpanded="True">
            <TreeViewItem Header="Category 1"/>
            <TreeViewItem Header="Category 2" ItemsSource="{Binding Images}">
                <TreeViewItem.ItemContainerStyle>
                    <Style TargetType="TreeViewItem">
                        <Setter Property="ContextMenu">
                            <Setter.Value>
                                <ContextMenu>
                                    <MenuItem Header="Remove"
                                              cal:Action.TargetWithoutContext="{Binding Path=DataContext, ElementName=projectTreeView}"
                                              cal:Message.Attach="[Event Click] = [Action RemoveResource()]"/>
                                </ContextMenu>
                            </Setter.Value>
                        </Setter>
                    </Style>
                </TreeViewItem.ItemContainerStyle>
                <TreeViewItem.ItemTemplate>
                    <HierarchicalDataTemplate>
                        <HierarchicalDataTemplate.ItemContainerStyle>
                            <Style TargetType="TreeViewItem">
                                <Setter Property="IsExpanded" Value="True" />
                                <Style.Triggers>
                                    <EventTrigger RoutedEvent="Collapsed">
                                        <EventTrigger.Actions>
                                            <BeginStoryboard>
                                                <Storyboard>
                                                    <BooleanAnimationUsingKeyFrames 
                                    Duration="0" 
                                    Storyboard.TargetProperty="(TreeViewItem.IsExpanded)">
                                                        <DiscreteBooleanKeyFrame KeyTime="0" Value="True" />
                                                    </BooleanAnimationUsingKeyFrames>
                                                </Storyboard>
                                            </BeginStoryboard>
                                        </EventTrigger.Actions>
                                    </EventTrigger>
                                </Style.Triggers>
                            </Style>
                        </HierarchicalDataTemplate.ItemContainerStyle>
                        <ContentControl cal:Action.TargetWithoutContext="{Binding Path=DataContext, ElementName=projectTreeView}"
                                        cal:Message.Attach="[Event MouseDoubleClick] = [Action OpenResource(projectTreeView.SelectedItem)]">
                            <StackPanel Orientation="Horizontal">
                                <TextBlock Text="{Binding ResourceName}" Margin="5,0,0,0"/>
                            </StackPanel>
                        </ContentControl>

                        <HierarchicalDataTemplate.ItemTemplate>
                            <DataTemplate>
                                <TextBlock Text="{Binding}"/>
                            </DataTemplate>
                        </HierarchicalDataTemplate.ItemTemplate>

                    </HierarchicalDataTemplate>
                </TreeViewItem.ItemTemplate>
            </TreeViewItem>
        </TreeViewItem>
    </TreeView>

附加的ViewModel包含两种方法：

The attached ViewModel contains both methods:

public class MyViewModel
{
    ...

    public void OpenResource(object obj) { ... }

    public void RemoveResource() { ... }

}

由于某种原因 OpenResource 可以完美运行，而当我单击上下文菜单项（右键单击后）时，应用程序崩溃，但出现以下异常：

For some reason OpenResource works perfectly, while when I click on the context menu item (after right click) the application crashes with the exception:

An unhandled exception of type 'System.Exception' occurred in WindowsBase.dll

Additional information: No target found for method RemoveResource.

我在论坛和支持论坛上发现了与同一问题有关的东西，

I found something related to the same problem here on the forum and on the support forum, but I was not able to fix the problem with those tips.

您对我的TreeView中发生的事情有任何了解吗？

Do you have any idea about what's going on in my TreeView?

非常感谢您的帮助！

推荐答案

ContextMenu 驻留在自己的可视树中，并且无法使用 ElementName 绑定到 TreeView 。

The ContextMenu resides in its own visual tree and can't bind to the TreeView using an ElementName.

您可以尝试将 TreeViewItem 的 Tag 属性绑定到父级 TreeView ，然后使用 ContextMenu PlacementTarget 属性绑定到它c>：

You could try to bind the Tag property of the TreeViewItem to the parent TreeView and then bind to it using the PlacementTarget property of the ContextMenu:

<Style TargetType="TreeViewItem">
    <Setter Property="Tag" Value="{Binding RelativeSource={RelativeSource AncestorType=TreeView}}" />
    <Setter Property="ContextMenu">
        <Setter.Value>
            <ContextMenu>
                <MenuItem Header="Remove"
                                  cal:Action.TargetWithoutContext="{Binding Path=PlacementTarget.Tag.DataContext, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ContextMenu}}"
                                  cal:Message.Attach="[Event Click] = [Action RemoveResource()]"/>
            </ContextMenu>
        </Setter.Value>
    </Setter>
</Style>

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