TreeView控件的ContextMenu MVVM绑定 [英] TreeView ContextMenu MVVM Binding

问题描述

我现在有一个使用MVVM模型用户控件。

在该控件有一个TreeView，它显示一些项目。我添加了一个HierarchicalDataTemplate为此TreeView和在该模板的项目将ContextMenu。

在视图模型，这是DataContext的控制（命名RestoresTreeViewControl）是我要绑定的菜单项目之一的命令。但是我做了什么似乎并不奏效。我越来越平常绑定参考无法找到来源。

下面是$ C $的c为试图将EditDatabaseCommand绑定到菜单项中的一个的DataTemplate中的比特。

 ＆LT; HierarchicalDataTemplate数据类型={X：类型模式：数据库}＆GT;
                    ＆LT;＆StackPanel的GT;
                        ＆LT; TextBlock的文本={绑定名称}＆GT;
                            ＆LT; TextBlock.ContextMenu＆GT;
                                ＆LT;＆文本菜单GT;
                                    ＆LT;菜单项标题=编辑命令={绑定的ElementName = RestoresTreeViewControl，路径= DataContext.EditDatabaseCommand}/＆GT;
                                    ＆LT;菜单项标题=删除/＆GT;
                                    ＆LT;分离器/＆GT;
                                    ＆LT;菜单项标题=测试连接/＆GT;
                                ＆LT; /文本菜单＆GT;
                            ＆LT; /TextBlock.ContextMenu>
                        ＆LT; / TextBlock的＆GT;
                    ＆LT; / StackPanel的＆GT;
                ＆LT; / HierarchicalDataTemplate＆GT;
 

下面是视图模型的一个部分，在那里的命令。

 公共ICommand的EditDatabaseCommand {搞定;私人集; }
 

解决方案

不幸的是，文本菜单不在的VisualTree，所以它不是会看到你的DateContext。你可以做的就是这样的事情（从这里复制： MVVM结合命令文本菜单项）

 ＆LT;按钮高度=40保证金=0,2,0,0CommandParameter ={绑定名称}
标签={绑定的RelativeSource = {的RelativeSource模式= FindAncestor，
      AncestorType = {X：类型用户控件}}}命令={结合
      的RelativeSource = {的RelativeSource模式= FindAncestor，AncestorType = {X：类型用户控件}}，
      路径= DataContext.ConnectCommand}＆GT;
        ＆LT; Button.ContextMenu＆GT;
            ＆LT;＆文本菜单GT;
                ＆LT;菜单项标题=删除
               CommandParameter ={绑定名称}
            命令={绑定路径= PlacementTarget.Tag.DataContext.RemoveCommand，
            的RelativeSource = {的RelativeSource模式= FindAncestor，AncestorType =文本菜单}}/＆GT;
            ＆LT; /文本菜单＆GT;
＆LT; /Button.ContextMenu>
 

所以，简单地用PlacementTarget.Tag找到你的视图模型。

I currently have a UserControl that uses the MVVM model.

In that control there is a TreeView, which displays some items. I have added a HierarchicalDataTemplate for this TreeView and in that template is a ContextMenu for the Items.

In the ViewModel, which is DataContext of the control (named RestoresTreeViewControl) is a command I want to bind one of the menu items to. However what I have done doesn't seem to be working. I am getting the usual can't find source for binding reference.

Here is the bit of code for the datatemplate that tried to bind the EditDatabaseCommand to one of the menu items.

<HierarchicalDataTemplate DataType="{x:Type model:Database}" >
                    <StackPanel>
                        <TextBlock Text="{Binding Name}" >
                            <TextBlock.ContextMenu>
                                <ContextMenu>
                                    <MenuItem Header="Edit" Command="{Binding ElementName=RestoresTreeViewControl, Path=DataContext.EditDatabaseCommand}" />
                                    <MenuItem Header="Delete"/>
                                    <Separator/>
                                    <MenuItem Header="Test Connection"/>
                                </ContextMenu>
                            </TextBlock.ContextMenu>
                        </TextBlock>
                    </StackPanel>
                </HierarchicalDataTemplate>

Here is a section of the ViewModel where the command is.

public ICommand EditDatabaseCommand { get; private set; }

解决方案

Unfortunately the ContextMenu is not in the VisualTree, so it's not gonna see your DateContext. What you can do is something like this (copied from here: MVVM binding command to contextmenu item)

<Button Height="40" Margin="0,2,0,0" CommandParameter="{Binding Name}" 
Tag="{Binding RelativeSource={RelativeSource Mode=FindAncestor, 
      AncestorType={x:Type UserControl}}}" Command = "{Binding 
      RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type UserControl}},
      Path=DataContext.ConnectCommand}">
        <Button.ContextMenu>
            <ContextMenu>
                <MenuItem Header="Remove" 
               CommandParameter="{Binding Name}"
            Command="{Binding Path=PlacementTarget.Tag.DataContext.RemoveCommand,
            RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ContextMenu}}"/>
            </ContextMenu>
</Button.ContextMenu>

So simply use PlacementTarget.Tag to find your ViewModel.

这篇关于TreeView控件的ContextMenu MVVM绑定的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！