我正在尝试使用TreeViewItem、KeyBinding和MenuContext执行ViewModel上的命令。当前,使用上下文菜单时,在正确的ViewModel实例上调用了该命令。但是,当我选择TreeViewItem并按下“C”键时,该命令会在“根”ViewModel上调用。我也尝试扩展KeyBinding类(Keybinding a RelayCommand),但没有成功。也许我走错了路:我只想在使用上下文菜单或按键时显示正确的MessageBox。以下是一个名为WpfTest的WPF项目的代码示例。
MainWindow.xaml
<Window x:Class="WpfTest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="clr-namespace:WpfTest"
Title="MainWindow" Height="350" Width="525">
<Grid>
<TreeView ItemsSource="{Binding}">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Child}" DataType="{x:Type vm:ViewModel}">
<TextBlock Text="{Binding Name}" />
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="ContextMenu">
<Setter.Value>
<ContextMenu>
<MenuItem Header="{Binding Name}" Command="{Binding SomeCommand}" CommandParameter="{Binding}"/>
</ContextMenu>
</Setter.Value>
</Setter>
<Setter Property="vm:MyAttached.InputBindings">
<Setter.Value>
<InputBindingCollection>
<KeyBinding Key="C" Command="{Binding SomeCommand}" CommandParameter="{Binding}"/>
</InputBindingCollection>
</Setter.Value>
</Setter>
</Style>
</TreeView.ItemContainerStyle>
</TreeView>
</Grid>
</Window>
MainWindow.xaml.cs:
namespace WpfTest
{
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Input;
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
this.DataContext = new List<ViewModel>
{
new ViewModel
{
Name = "Parent",
Child = new ObservableCollection<ViewModel>
{
new ViewModel { Name = "Child 1" },
new ViewModel { Name = "Child 2" },
new ViewModel { Name = "Child 3" }
}
}
};
}
}
public class ViewModel
{
public string Name { get; set; }
public ObservableCollection<ViewModel> Child { get; set; }
public ICommand SomeCommand { get; set; }
public ViewModel()
{
this.SomeCommand = new RelayCommand<ViewModel>(OnCommandExecuted);
}
private void OnCommandExecuted(ViewModel parameter)
{
MessageBox.Show("CommandExecuted on " + Name + " with parameter " + parameter.Name);
}
}
public class MyAttached
{
public static readonly DependencyProperty InputBindingsProperty =
DependencyProperty.RegisterAttached("InputBindings", typeof(InputBindingCollection), typeof(MyAttached),
new FrameworkPropertyMetadata(new InputBindingCollection(),
(sender, e) =>
{
var element = sender as UIElement;
if (element == null) return;
element.InputBindings.Clear();
element.InputBindings.AddRange((InputBindingCollection)e.NewValue);
}));
public static InputBindingCollection GetInputBindings(UIElement element)
{
return (InputBindingCollection)element.GetValue(InputBindingsProperty);
}
public static void SetInputBindings(UIElement element, InputBindingCollection inputBindings)
{
element.SetValue(InputBindingsProperty, inputBindings);
}
}
public class RelayCommand<T> : ICommand
{
readonly Action<T> _execute = null;
public RelayCommand(Action<T> execute) { _execute = execute; }
public bool CanExecute(object parameter) { return true; }
public void Execute(object parameter) { _execute((T)parameter); }
public event EventHandler CanExecuteChanged { add { CommandManager.RequerySuggested += value; } remove { CommandManager.RequerySuggested -= value; } }
}
}