Question

我正在努力让这个绑定工作在我的ContextMenu上。

我正在使用Items Source，因此每个项目都是frm ItemsSource类型，所以我需要搜索树以获得正确的绑定上下文。

我试图执行的命令存在于ContextMenu的DataContext中，你可以看到它绑定在这里：

DataContext="{Binding PlacementTarget, RelativeSource={RelativeSource Self}}"

所以我尝试使用RelativeSource绑定到该数据上下文，但无论我尝试过什么，我总是会遇到绑定错误：

System.Windows.Data Error: 40 : BindingExpression path error: 'CreateNodeCommand' property not found on 'object' ''NodeGraphView' (Name='networkControl')'. BindingExpression:Path=DataContext.CreateNodeCommand; DataItem='ContextMenu' (Name='NodeGraphRightClickMenu'); target element is 'MenuItem' (Name=''); target property is 'Command' (type 'ICommand')

以下是代码：

  <ContextMenu x:Name="NodeGraphRightClickMenu" DataContext="{Binding PlacementTarget, RelativeSource={RelativeSource Self}}" ItemsSource="{Binding DataContext.PolymorphicTypes}">
<ContextMenu.ItemContainerStyle>
    <Style TargetType="MenuItem">
        <Setter Property="Command" Value="{Binding DataContext.CreateNodeCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ContextMenu}}"/>
        <Setter Property="CommandParameter">
            <Setter.Value>
                <MultiBinding Converter="{convertersDF:Converter_MultiBindingToArray}">
                    <Binding Path="."></Binding>
                    <Binding Path="Name"></Binding>
                </MultiBinding>
            </Setter.Value>
        </Setter>
        <Setter Property="Header">
            <Setter.Value>
                <Binding StringFormat="Create {0}" Path="Name"></Binding>
            </Setter.Value>
        </Setter>
    </Style>
</ContextMenu.ItemContainerStyle>

任何帮助都非常感激。

Answer 1

答案是如此明显。我需要绑定到DataContext的DataContext。这令人困惑所以我重写了它：

                                <ContextMenu x:Name="NodeGraphRightClickMenu" DataContext="{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}" ItemsSource="{Binding PolymorphicTypes}">
                                    <ContextMenu.ItemContainerStyle>
                                        <Style TargetType="MenuItem">
                                            <Setter Property="Command" Value="{Binding DataContext.CreateNodeCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ContextMenu}}"/>
                                            <Setter Property="CommandParameter">
                                                <Setter.Value>
                                                    <MultiBinding Converter="{convertersDF:Converter_MultiBindingToArray}">
                                                        <Binding Path="."></Binding>
                                                        <Binding Path="Name"></Binding>
                                                    </MultiBinding>
                                                </Setter.Value>
                                            </Setter>
                                            <Setter Property="Header">
                                                <Setter.Value>
                                                    <Binding StringFormat="Create {0}" Path="Name"></Binding>
                                                </Setter.Value>
                                            </Setter>
                                        </Style>
                                    </ContextMenu.ItemContainerStyle>
                                </ContextMenu>

ContextMenu使用MVVM（ItemsSource）尝试查找DataContext

1 个答案: