Caliburn Micro未在ListView中的ContextMenu中找到DataContext

Question

我用对象填充了ListView,并将ContextMenu绑定到ListView中的那些项目.只能通过单击项目来打开ContextMenu.问题是Caliburn Micro抛出一个错误,它无法找到ShowProperties()的目标方法.

我认为出现此问题是因为Caliburn没有可用的ViewModel的正确DataContext.我在Stackoverflow上尝试了很多解决方案,使ViewModel可用于ContextMenu项目,但无济于事,例如:

WPF:将ContextMenu绑定到MVVM命令

Caliburn Message.Attach()抛出"找不到方法的目标"

Caliburn Micro中的WPF上下文菜单

这是我的观点的XAML代码:

<Window x:Class="CueMaster.Views.AppView"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:dragDrop="clr-namespace:GongSolutions.Wpf.DragDrop;assembly=GongSolutions.Wpf.DragDrop"
         xmlns:cal="http://www.caliburnproject.org"
         Height="500" Width="800">
<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="*" />
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="200" />
        <ColumnDefinition Width="*" />
    </Grid.ColumnDefinitions>

    <ListView Grid.Column="1" Margin="5"
        ItemsSource="{Binding Cues}" 
        dragDrop:DragDrop.IsDragSource="True" 
        dragDrop:DragDrop.IsDropTarget="True"
        dragDrop:DragDrop.DropHandler="{Binding}">

        <ListView.Resources>
            <ContextMenu x:Key="ItemContextMenu">
                <MenuItem Header="Properties" cal:Message.Attach="ShowProperties($dataContext)" Command="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ListView}}">
                    <MenuItem.Icon>
                        <Image Source="../PropertyIcon.png" />
                    </MenuItem.Icon>
                </MenuItem>
            </ContextMenu>
        </ListView.Resources>

        <ListView.ItemContainerStyle>
            <Style TargetType="{x:Type ListViewItem}" >
                <Setter Property="ContextMenu" Value="{StaticResource ItemContextMenu}" />
            </Style>
        </ListView.ItemContainerStyle>

        <ListView.View>
            <GridView >
                <GridViewColumn Width="70" Header="Cue"  DisplayMemberBinding="{Binding Id}" />
                <GridViewColumn Width="100" Header="Name"  DisplayMemberBinding="{Binding Name}" />
                <GridViewColumn Width="100" Header="Description"  DisplayMemberBinding="{Binding Description}" />
                <GridViewColumn Width="70" Header="Duration"  DisplayMemberBinding="{Binding Duration}" />
                <GridViewColumn Width="70" Header="Elapsed"  DisplayMemberBinding="{Binding Elapsed}" />
                <GridViewColumn Width="70" Header="Remaining"  DisplayMemberBinding="{Binding Remaining}" />
            </GridView>
        </ListView.View>
    </ListView>
</Grid>

我错过了什么？

Answer 1

您可以通过放置Command绑定来覆盖CM将执行的操作.由于可视树不知道上下文菜单存在,更不用说背后目的的datacontext.

<ListView.ItemContainerStyle>
<Style TargetType="{x:Type ListViewItem}">
    <Setter Property="Tag" Value="{Binding Path=DataContext, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ListView}}"/>
    <Setter Property="ContextMenu">
        <Setter.Value>
            <ContextMenu cal:Action.TargetWithoutContext="{Binding Path=PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
               <MenuItem Header="Properties"  cal:Message.Attach="ShowProperties($dataContext)" >
                <MenuItem.Icon>
                    <Image Source="../PropertyIcon.png" />
                </MenuItem.Icon>
            </MenuItem>
            </ContextMenu>
        </Setter.Value>
    </Setter>
</Style>
</ListView.ItemContainerStyle>

虽然我理解你在使用ListView中的资源尝试做什么,但是你正在使用Command绑定自己.删除资源给ItemContainerStyle一个roll并查看它是否有效.您可以随时将其分解为资源.为了测试目的,看它是否有效现在尝试内部风格.