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如何将命令绑定到动态上下文菜单

prism contextmenu wpf c#

sflee · 技术社区 · 5 年前

我使用c#、prism、wpf。我想在列表视图中动态创建一个上下文列表,如下图所示:

当我单击这些菜单项时,它将回调到我的自定义函数。在该函数中,我可以识别单击了哪个菜单项,例如,我可以获取菜单项的标题。

我尝试添加一个命令标记并绑定到ICommand。但当我点击它时,没有任何反应。

我读过网络上的不同示例,但它们从未同时显示xaml和viewmodel的实现。我想问一下怎么做?非常感谢你。

在App.xaml.cs中:

ViewModelLocationProvider.Register<MainWindowView, MainWindowViewModel>();

以下是我的名字:

<ListView Grid.Row="2"  ItemsSource="{Binding ServiceObjects}" ItemContainerStyle="{StaticResource LstBoxItemStyleNormal}">
    <ListView.ItemTemplate>
        <DataTemplate>
            <Grid>
                <TextBlock Text="{Binding ServiceName}">
                    <TextBlock.ContextMenu>
                        <ContextMenu ItemsSource="{Binding ContextMenuList}">
                            <ContextMenu.ItemTemplate>
                                <HierarchicalDataTemplate>
                                    <MenuItem Header="{Binding MenuName}" Command="{Binding ConfirmButtonCommand}"/>
                                </HierarchicalDataTemplate>
                            </ContextMenu.ItemTemplate>
                        </ContextMenu>
                    </TextBlock.ContextMenu>
                </TextBlock>
            </Grid>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

以下是我的视图模型:

class MainWindowViewModel : BindableBase
{
    public class MenuNode : BindableBase
    {
        private string _menuName;
        public string MenuName
        {
            get => _menuName;
            set => SetProperty(ref _menuName, value);
        }
    }
    public class ServiceNode : BindableBase
    {
        private string _serviceName;
        public string ServiceName
        {
            get => _serviceName;
            set => SetProperty(ref _serviceName, value);
        }
        public ObservableCollection<MenuNode> ContextMenuList { get; } = new ObservableCollection<MenuNode>();
    }
    public ObservableCollection<ServiceNode> ServiceObjects { get; } = new ObservableCollection<ServiceNode>();
    
    public MainWindowViewModel()
    {
        for (int i = 0; i < 10; i++)
        {
            ServiceNode tempNode = new ServiceNode { ServiceName = "AP", State = "Normal" };
            tempNode.ContextMenuList.Add(new MenuNode { MenuName = "A Item" });
            tempNode.ContextMenuList.Add(new MenuNode { MenuName = "B Item" });
            tempNode.ContextMenuList.Add(new MenuNode { MenuName = "C Item" });
            ServiceObjects.Add(tempNode);
        }
        ConfirmButtonCommand = new DelegateCommand(HandleConfirmButtonCommand);
    }
    public ICommand ConfirmButtonCommand { get; }

    private void HandleConfirmButtonCommand()
    {
        
    }

1 回复 | 直到 5 年前

Quercus 5 年前

首先,绑定到 Command 对于 MenuItem 应该是花括号: {Binding ConfirmButtonCommand} .
其次,您的命令定义在 MainWindowViewModel 类,而 DataContext 对于 菜单项 是 MenuNode ,因此找不到该命令。
最简单的修复方法是-命名 List 当绑定到命令时,请参考其 数据上下文 .
例如:

<ListView x:Name="list" ...>

然后

<MenuItem Header="{Binding MenuName}" Command="{Binding DataContext.ConfirmButtonCommand, ElementName=list}"/>

此外,对于命令,您可能还需要知道 ServiceNode 它被点击了,你可以通过 CommandParameter (取 数据上下文 从 ContextMenu 这是成立的 菜单项 ):

<MenuItem ... CommandParameter="{Binding DataContext, RelativeSource={RelativeSource FindAncestor, AncestorType=ContextMenu}}">

sflee 5 年前

这是我最后使用的答案。谢谢

在App.xaml.cs中:

ViewModelLocationProvider.Register<MainWindowView, MainWindowViewModel>();

以下是我的名字:

<ListView Grid.Row="2"  ItemsSource="{Binding ServiceObjects}" ItemContainerStyle="{StaticResource LstBoxItemStyleNormal}">
    <ListView.ItemTemplate>
        <DataTemplate>
            <Grid>
                <TextBlock Text="{Binding ServiceName}" Tag="{Binding DataContext, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ListView}}">
                    <TextBlock.ContextMenu>
                        <ContextMenu ItemsSource="{Binding ContextMenuList}">
                            <ContextMenu.ItemTemplate>
                                <HierarchicalDataTemplate>
                                    <MenuItem Header="{Binding MenuName}"
                                              Command="{Binding PlacementTarget.Tag.ConfirmButtonCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ContextMenu}}"
                                              CommandParameter="Binding MenuName"/>
                                </HierarchicalDataTemplate>
                            </ContextMenu.ItemTemplate>
                        </ContextMenu>
                    </TextBlock.ContextMenu>
                </TextBlock>
            </Grid>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

以下是我的视图模型:

class MainWindowViewModel : BindableBase
{
    public class MenuNode : BindableBase
    {
        private string _menuName;
        public string MenuName
        {
            get => _menuName;
            set => SetProperty(ref _menuName, value);
        }
    }
    public class ServiceNode : BindableBase
    {
        private string _serviceName;
        public string ServiceName
        {
            get => _serviceName;
            set => SetProperty(ref _serviceName, value);
        }
        public ObservableCollection<MenuNode> ContextMenuList { get; } = new ObservableCollection<MenuNode>();
    }
    public ObservableCollection<ServiceNode> ServiceObjects { get; } = new ObservableCollection<ServiceNode>();
    
    public MainWindowViewModel()
    {
        for (int i = 0; i < 10; i++)
        {
            ServiceNode tempNode = new ServiceNode { ServiceName = "AP", State = "Normal" };
            tempNode.ContextMenuList.Add(new MenuNode { MenuName = "A Item" });
            tempNode.ContextMenuList.Add(new MenuNode { MenuName = "B Item" });
            tempNode.ContextMenuList.Add(new MenuNode { MenuName = "C Item" });
            ServiceObjects.Add(tempNode);
        }
        ConfirmButtonCommand = new DelegateCommand<string>(HandleConfirmButtonCommand);
    }
    public ICommand ConfirmButtonCommand { get; }

    private void HandleConfirmButtonCommand(string parameter)
    {
        
    }