WFP数据库依赖项

Question

在发布我的XAML之前，总结一下，这个表单现在非常简单。有一个ListBox、两个按钮和一个ListBox上下文菜单。

如果在ListBox中单击鼠标右键，而没有选择任何元素，则我的上下文菜单将执行添加操作，该操作现在只是简单地弹出一个消息框。

当选择元素(例如修改)时，我的绑定不起作用。因此，我认为，经过大量阅读，我在某个地方有继承问题。我试过用DataContext，RelativeSource，etc...and，仍然没有joy。

这是我的XAML

<Window x:Class="FracasReportSettings.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:ignore="http://www.ignore.com"
    mc:Ignorable="d ignore"
    Height="402"
    Width="578"
    Title="FRACAS Ticket Value Modification"
    DataContext="{Binding Main, Source={StaticResource Locator}}">

<Window.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="Skins/MainSkin.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Window.Resources>

<Grid x:Name="LayoutRoot">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="91*"/>
        <ColumnDefinition Width="194*"/>
    </Grid.ColumnDefinitions>

    <TextBlock FontSize="36"
               FontWeight="Bold"
               Foreground="Purple"
               Text="{Binding PageTitle}"
               VerticalAlignment="Center"
               HorizontalAlignment="Center"
               TextWrapping="Wrap" Margin="266,27,10,9" Width="112" Grid.Column="1" />

    <StackPanel HorizontalAlignment="Left" Height="311" Margin="40,22,0,0" VerticalAlignment="Top" Width="111">
        <Button Content="Detection Method" Margin="10,10,10,10"
                Command="{Binding MyBinding}"
                CommandParameter="DetectionMethod"/>
        <Button Content="Button" Margin="10,0,10,0"/>
    </StackPanel>

    <ListBox 
        Name="AdminList"
        ItemsSource="{Binding Names}"
        Height="302"  Width="231" Margin="151,22,0,0"
        HorizontalAlignment="Left"   VerticalAlignment="Top" Grid.ColumnSpan="2"
        SelectedItem="{Binding SomeName}"
       >

        <ListBox.Resources>
            <Style TargetType="ListBoxItem">
                <Style.Triggers>
                    <Trigger Property="IsKeyboardFocusWithin" Value="True">
                        <Setter Property="IsSelected" Value="True"/>
                    </Trigger>                                 
                </Style.Triggers> 
            </Style>                
        </ListBox.Resources>

       **<-- THIS WORKS FINE -->
       <ListBox.ContextMenu>
            <ContextMenu>
                <MenuItem Header="Add"                             
                          Command="{Binding RCContentMenu}">                        
                </MenuItem>
            </ContextMenu>
        </ListBox.ContextMenu>**

        <--MY ERROR IS IN HERE-->
        **<ListBox.ItemContainerStyle>                
            <Style TargetType="ListBoxItem">                    
                <Setter Property="ContextMenu">
                    <Setter.Value>
                        <ContextMenu DataContext="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListBox}}, Path=DataContext}">
                            <MenuItem Header="Modify"                                           
                                Command="{Binding Path=ModifyElementCommand}"
                                CommandParameter="{Binding Path=SelectedItem}"/>

                        </ContextMenu>
                    </Setter.Value>                        
                </Setter>
            </Style>
        </ListBox.ItemContainerStyle>**

    </ListBox>
</Grid>

​

ModifyElementCommand坐在一个名为MainViewModel的ViewModel中。

从输出窗口收到的错误是：

AncestorType='System.Windows.Controls.ListBox'，System.Windows.Data错误:4:无法找到引用'RelativeSource FindAncestor，RelativeSource AncestorLevel=‘1’绑定的源代码。BindingExpression:Path=DataContext；DataItem=null；目标元素是'ContextMenu‘(名称=’‘)；目标属性是'DataContext’(键入'Object')

我知道这意味着无法找到依赖性。

我该怎么做才能解决这个问题？

Answer 1

下面我的评论是XAML：

<ListBox.ItemContainerStyle>
    <Style TargetType="ListBoxItem">
        <Setter Property="ContextMenu">
            <Setter.Value>
                <ContextMenu DataContext="{Binding RelativeSource={RelativeSource Self},Path=PlacementTarget.Tag.DataContext}">
                    <MenuItem Header="Modify"                                           
                    Command="{Binding Path=ModifyElementCommand}"
                    CommandParameter="{Binding Path=SelectedItem}"/>

                </ContextMenu>
            </Setter.Value>
        </Setter>
        <Setter Property="Tag" Value="{Binding ElementName=AdminList}" />
    </Style>
</ListBox.ItemContainerStyle>