c# – WPF – 如何使用绑定创建菜单和子菜单

我正在尝试使用绑定创建一个动态菜单.我的viewmodel我有一个包含头和命令的对象列表.但是,它不工作.我认为问题在数据模板中.请参阅我的代码：

<Menu Background="{x:Null}" Grid.Row="0" Grid.Column="1" Panel.ZIndex="2" Width="865" Height="85" HorizontalAlignment="Left" ItemsSource="{Binding Path=MenuItems}">

        <Menu.ItemTemplate>
            <HierarchicalDataTemplate DataType="MenuItemviewmodel" ItemsSource="{Binding Path=MenuItems}">
                <MenuItem Header="{Binding Header}" Style="{DynamicResource MenuItemStyle1}" ItemsSource="{Binding Path=MenuItems}" Padding="10,12,10,0" Height="44.1" Margin="30,0" FontWeight="Bold">
                    <MenuItem.ItemsPanel>
                        <ItemsPanelTemplate>
                            <VirtualizingStackPanel Orientation="Horizontal"/>
                        </ItemsPanelTemplate>
                    </MenuItem.ItemsPanel>
                </MenuItem>
                <HierarchicalDataTemplate.ItemTemplate>
                    <DataTemplate>
                        <MenuItem Header="{Binding Header}" Style="{DynamicResource MenuItemStyle1}" Padding="0,8,0" Height="38">
                        </MenuItem>
                    </DataTemplate>
                </HierarchicalDataTemplate.ItemTemplate>
            </HierarchicalDataTemplate>
        </Menu.ItemTemplate>            
    </Menu>

结果只显示第一个菜单.子菜单没有显示,但是它们在那里,因为有孩子的菜单,箭头在菜单标题后打印.

有没有人会发现绑定有问题？还是任何建议？

MenuItems是MenuItemviewmodel对象的列表,它有一个名为MenuItems的MenuItemviewmodel对象(子菜单)的头和列表.

解决方法

对我来说,它与这个简单的模板一起工作：

<Menu.ItemContainerStyle>
    <Style TargetType="{x:Type MenuItem}">
        <Setter Property="Command" Value="{Binding Command}" />
    </Style>
</Menu.ItemContainerStyle>
<Menu.ItemTemplate>
    <HierarchicalDataTemplate DataType="{x:Type local:MenuItemviewmodel}" ItemsSource="{Binding Path=MenuItems}">
        <TextBlock Text="{Binding Header}"/>
    </HierarchicalDataTemplate>
</Menu.ItemTemplate>

这是完整的例子：

MainWindow.xaml：

<Window x:Class="WpfApplication14.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfApplication14"
        Title="MainWindow" Height="350" Width="525">
    <DockPanel>
        <Menu DockPanel.Dock="Top" ItemsSource="{Binding MenuItems}">
            <Menu.ItemContainerStyle>
                <Style TargetType="{x:Type MenuItem}">
                    <Setter Property="Command" Value="{Binding Command}" />
                </Style>
            </Menu.ItemContainerStyle>
            <Menu.ItemTemplate>
                <HierarchicalDataTemplate DataType="{x:Type local:MenuItemviewmodel}" ItemsSource="{Binding Path=MenuItems}">
                    <TextBlock Text="{Binding Header}"/>
                </HierarchicalDataTemplate>
            </Menu.ItemTemplate>
        </Menu>
        <Grid>
        </Grid>
    </DockPanel>
</Window>

MainWindow.xaml.cs：

using System;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Input;

namespace WpfApplication14
{
    public partial class MainWindow : Window
    {
        public ObservableCollection<MenuItemviewmodel> MenuItems { get; set; }

        public MainWindow()
        {
            InitializeComponent();

            MenuItems = new ObservableCollection<MenuItemviewmodel>
            {
                new MenuItemviewmodel { Header = "Alpha" },new MenuItemviewmodel { Header = "Beta",MenuItems = new ObservableCollection<MenuItemviewmodel>
                        {
                            new MenuItemviewmodel { Header = "Beta1" },new MenuItemviewmodel { Header = "Beta2",MenuItems = new ObservableCollection<MenuItemviewmodel>
                                {
                                    new MenuItemviewmodel { Header = "Beta1a" },new MenuItemviewmodel { Header = "Beta1b" },new MenuItemviewmodel { Header = "Beta1c" }
                                }
                            },new MenuItemviewmodel { Header = "Beta3" }
                        }
                },new MenuItemviewmodel { Header = "Gamma" }
            };

            DataContext = this;
        }
    }

    public class MenuItemviewmodel
    {
        private readonly ICommand _command;

        public MenuItemviewmodel()
        {
            _command = new Commandviewmodel(Execute);
        }

        public string Header { get; set; }

        public ObservableCollection<MenuItemviewmodel> MenuItems { get; set; }

        public ICommand Command
        {
            get
            {
                return _command;
            }
        }

        private void Execute()
        {
            // (NOTE: In a view model,you normally should not use MessageBox.Show()).
            MessageBox.Show("Clicked at " + Header);
        }
    }

    public class Commandviewmodel : ICommand
    {
        private readonly Action _action;

        public Commandviewmodel(Action action)
        {
            _action = action;
        }

        public void Execute(object o)
        {
            _action();
        }

        public bool CanExecute(object o)
        {
            return true;
        }

        public event EventHandler CanExecuteChanged
        {
            add { }
            remove { }
        }
    }
}

结果窗口如下所示：

c# – WPF – 如何使用绑定创建菜单和子菜单

解决方法

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