Question

我遇到了WPF事件触发器的问题：

在我的xaml中我得到了一个箭头：

<Path Data="{Binding Path=Points, Converter={StaticResource ResourceKey=pointCollectionConverter}}"
              Stroke="Black"
              MinWidth="1"
              MinHeight="1"
              Name="arrowPath"
              StrokeThickness="2">
            <i:Interaction.Triggers>
                <i:EventTrigger EventName="MouseLeftButtonDown">
                    <cmd:EventToCommand Command="{Binding Path=ArrowPathMouseLeftButtonDownCommand}"
                                        PassEventArgsToCommand="True"></cmd:EventToCommand>
                </i:EventTrigger>
                <i:EventTrigger EventName="MouseRightButtonDown">
                    <cmd:EventToCommand Command="{Binding Path=ArrowPathMouseRightButtonDownCommand}"
                                        PassEventArgsToCommand="True"></cmd:EventToCommand>
                </i:EventTrigger>
            </i:Interaction.Triggers>
        </Path>

事件正在按预期触发，一切都很好。现在我得到了一些Ellypses（在同一个xaml中），它应该像鼠标右键单击箭头一样。

所以我在我的xaml中添加了Ellypses触发器部分：

<ItemsControl ItemsSource="{Binding Points}">
        <ItemsControl.ItemsPanel>
            <ItemsPanelTemplate>
                <controls:DragCanvas AllowDragOutOfView="True" />
            </ItemsPanelTemplate>
        </ItemsControl.ItemsPanel>
        <ItemsControl.ItemTemplate>
            <DataTemplate>
                <Ellipse  Cursor="Hand"
                          Fill="Black"
                          Stroke="Black"
                          StrokeThickness="2"
                          Width="10"
                          Height="10"
                          Visibility="{Binding Visible, Converter={StaticResource ResourceKey=endPointTrimmer}}">
                    <i:Interaction.Triggers>
                        <i:EventTrigger EventName="MouseRightButtonDown">
                            <cmd:EventToCommand Command="{Binding Path=ArrowPathMouseRightButtonDownCommand}"
                                                PassEventArgsToCommand="True"></cmd:EventToCommand>
                        </i:EventTrigger>
                    </i:Interaction.Triggers>
                </Ellipse>
            </DataTemplate>
        </ItemsControl.ItemTemplate>
        <ItemsControl.ItemContainerStyle>
            <Style TargetType="ContentPresenter">
                <Setter Property="Canvas.Left"
                        Value="{Binding X, Mode=TwoWay}" />
                <Setter Property="Canvas.Top"
                        Value="{Binding Y, Mode=TwoWay}" />
            </Style>
        </ItemsControl.ItemContainerStyle>
    </ItemsControl>

但是我收到了绑定错误：

System.Windows.Data Error: 40 : BindingExpression path error: 'ArrowPathMouseRightButtonDownCommand' property not found on 'object' ''ConnectionPoint' (HashCode=54168362)'. BindingExpression:Path=ArrowPathMouseRightButtonDownCommand; DataItem='ConnectionPoint' (HashCode=54168362); target element is 'EventToCommand' (HashCode=42719917); target property is 'Command' (type 'ICommand')

我不明白为什么。请任何人帮助我

Answer 1

你必须使用Ancestor Relative Source Binding。喜欢

<cmd:EventToCommand Command="{Binding Path=ArrowPathMouseRightButtonDownCommand,RelativeSource={RelativeSource
                    Mode=FindAncestor,
                    AncestorType=Path}}"
                                                PassEventArgsToCommand="True"></cmd:EventToCommand>

Answer 2

为了获得与ItemsControl相同的ViewModel（即数据上下文）的访问权限，您必须为您的商品控制一个名称，例如像这样：

<ItemsControl x:Name="itemsCtrl" ...>

然后您可以使用以下绑定来访问ViewModel中的ArrowPathMouseRightButtonDownCommand属性：

{Binding Path=DataContext.ArrowPathMouseRightButtonDownCommand, ElementName=itemsCtrl}

WPF绑定中的事件触发器不起作用

2 个答案: