Question

我想在WPF应用程序中实现导航。目前StartScreen.xaml在启动时显示，但是当我单击按钮时，未显示DeviceManagement.xaml。甚至不会调用 ShowDeviceManagement 命令。

这让我假设 Button 的 Command 不正确？我该如何解决？

的App.xaml

<Application.Resources>
    <DataTemplate DataType="{x:Type vm:DeviceManagementViewModel}">
        <view:DeviceManagement />
    </DataTemplate>

    <DataTemplate DataType="{x:Type vm:MainWindowViewModel}">
        <view:StartScreen />
    </DataTemplate>
</Application.Resources>

MainWindow.xaml

<Window ...>
    <Window.DataContext>
        <vm:MainWindowViewModel/>
    </Window.DataContext>
    <ContentControl
        Content="{Binding ViewModel}">
    </ContentControl>
</Window>

StartScreen.xaml

<UserControl ...>
     <Button
         Content="Click Me"
         Command="{Binding DataContext.ShowDeviceManagement, RelativeSource={RelativeSource AncestorType={x:Type vm:MainWindowViewModel}}, Mode=OneWay}"/>
</UserControl>

MainWindoViewModel.cs

class MainWindowViewModel : ViewModelBase
{
    public ViewModelBase ViewModel { get; set; }

    public MainWindowViewModel()
    {
        ViewModel = this;
    }

    public ICommand ShowDeviceManagement
    {
        get
        {
            return new RelayCommand(action => ViewModel = new DeviceManagementViewModel());
        }
    }
}

Answer 1

“DataContext”在命令绑定中已过时。 RelativeSource用于在可视树中查找祖先，而您的MainWindowViewModel不是Visual。应该是这样的：

Command="{Binding ShowDeviceManagement, Mode=OneWay}"

在WPF应用程序中未正确执行Command-Binding

1 个答案: