菜单单击未触发其绑定命令

Question

我从这个视图开始：

<Window x:Class="MyApp.UI.Views.MainView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:MyApp.UI.Views"
        mc:Ignorable="d"
        Title="MyApp" Height="300" Width="500" WindowStartupLocation="CenterScreen">
  <Grid>
    <Button
      HorizontalAlignment="Left"
      VerticalAlignment="Top"
      Command="{Binding ShutdownCommand}"
      Content="_Exit" 
      Margin="390,225,0,0"
      Width="75"/>
  </Grid>
</Window>

Code-behind

Imports MyApp.UI.ViewModels

Namespace MyApp.UI.Views
  Public Class MainView
    Public Sub New(ViewModel As IMainViewModel)
      Me.InitializeComponent()

      Me.ViewModel = ViewModel
      Me.DataContext = Me.ViewModel
    End Sub

    Private Sub MainView_Loaded(Sender As MainView, e As RoutedEventArgs) Handles Me.Loaded
      Me.ViewModel.Load
    End Sub

    Private ReadOnly ViewModel As MainViewModel
  End Class
End Namespace

ViewModel

Imports MyApp.UI.Commands

Namespace MyApp.UI.ViewModels
  Public Class MainViewModel
    Implements IMainViewModel

    Public Sub New()
      Me.ShutdownCommand = New DelegateCommand(AddressOf Me.Shutdown)
    End Sub

    Public Sub Shutdown() Implements IMainViewModel.Shutdown
      Application.Current.Shutdown()
    End Sub

    Public Sub Load() Implements IMainViewModel.Load
    End Sub

    Public ReadOnly Property ShutdownCommand As ICommand
  End Class
End Namespace

DelegateCommand

Imports Intexx

Namespace MyApp.UI.Commands
  Public Class DelegateCommand
    Implements ICommand

    Public Sub New(Execute As Action(Of Object))
      Me.New(Execute, Nothing)
    End Sub

    Public Sub New(Execute As Action(Of Object), CanExecute As Func(Of Object, Boolean))
      If Execute.IsNothing Then
        Throw New ArgumentNullException(NameOf(Execute))
      Else
        Me._CanExecute = CanExecute
        Me._Execute = Execute
      End If
    End Sub

    Public Function CanExecute(Parameter As Object) As Boolean Implements ICommand.CanExecute
      Return Me._CanExecute.IsNothing OrElse Me._CanExecute(Parameter)
    End Function

    Public Sub Execute(Parameter As Object) Implements ICommand.Execute
      Me._Execute(Parameter)
    End Sub

    Public Sub RaiseCanExecuteChanged()
      RaiseEvent CanExecuteChanged(Me, EventArgs.Empty)
    End Sub

    Public Event CanExecuteChanged As EventHandler Implements ICommand.CanExecuteChanged

    Private ReadOnly _CanExecute As Func(Of Object, Boolean)
    Private ReadOnly _Execute As Action(Of Object)
  End Class
End Namespace

单击 Exit 按钮按预期工作。应用程序退出。

然后我添加了一个菜单：

<Window x:Class="MyApp.UI.Views.MainView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:MyApp.UI.Views"
        mc:Ignorable="d"
        Title="MyApp" Height="300" Width="500" WindowStartupLocation="CenterScreen">
  <Grid>
    <Menu>
      <MenuItem Header="_File">
        <MenuItem
          Header="E_xit"
          Command="{Binding ShutDownCommand}"/>
      </MenuItem>
      <MenuItem Header="_Help">
        <MenuItem Header="_About MyApp"/>
      </MenuItem>
    </Menu>
    <Button
      HorizontalAlignment="Left"
      VerticalAlignment="Top"
      Command="{Binding ShutdownCommand}"
      Content="_Exit" 
      Margin="390,225,0,0"
      Width="75"/>
  </Grid>
</Window>

单击 Exit 按钮仍然有效，但单击 File=>Exit 没有任何结果。我没有在我的 code-behind 或我的 ViewModel 中进行任何更改。

This one相关，但不完全相同。我的 MenuItem 与绑定命令是 child，而不是 parent。

我在这里错过了什么？为什么 File=>Exit 单击不调用绑定命令？

Answer 1

好的，明白了。

作为 WPF 的新手，我忘记了命令绑定（除其他事项外）区分大小写。

当我将 MenuItem 的命令绑定从 ShutDownCommand 更改为 ShutdownCommand 时，它起作用了。应用程序按预期退出。

要是 IntelliSense 能在这里工作就好了。

菜单单击未触发其绑定命令

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