具有多个视图的 WPF 加上 Prism 和 Unity

Question

我必须用 WPF C# 编写应用程序。我的问题是我不知道如何使用多个视图。直到知道我知道如何使用 Prism 在基本级别通过绑定将 ViewModel 连接到 View。通过覆盖 OnStartup 方法和使用 UnityContainer，我学会了一些 Unity 来注册 ViewModel 到 App.xml.cs 中的视图。

我想知道如何从视图 1 导航到视图 2，反之亦然。我想通过一个按钮导航，但视图不同。

你能帮帮我吗？有什么建议吗？

像这样，退相干！

Answer 1

我有一个我很久以前写的例子，它不需要任何框架废话，根据我的经验，WPF MVVM 框架在大多数情况下是无用的，并且往往会使简单的事情复杂化你所需要的只是一个 ICommand 实现和实现 INotiftyPropertyChanged 的 ViewModelBase，这是一个简单的说明：

XML:

   <Window.Resources>
        <DataTemplate DataType="{x:Type local:ViewModel1}">
            <local:View1/>
        </DataTemplate>
        <DataTemplate DataType="{x:Type local:ViewModel2}">
            <local:View2/>
        </DataTemplate>
        <DataTemplate DataType="{x:Type local:ViewModel3}">
            <local:View3/>
        </DataTemplate>
    </Window.Resources>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*"></RowDefinition>
            <RowDefinition></RowDefinition>
        </Grid.RowDefinitions>
        <ContentControl Content="{Binding CurrentViewModel}">
        </ContentControl>

        <StackPanel Orientation="Horizontal" Grid.Row="1" VerticalAlignment="Bottom">
            <Button Command="{Binding PrevViewModel}">Previouws View</Button>
            <Button Command="{Binding NextViewModel}">Next View</Button>
            <Button Command="{Binding SwitchToViewModel}" CommandParameter="{x:Type local:ViewModel1}">Switch To View1</Button>
            <Button Command="{Binding SwitchToViewModel}" CommandParameter="{x:Type local:ViewModel2}">Switch To View2</Button>
            <Button Command="{Binding SwitchToViewModel}" CommandParameter="{x:Type local:ViewModel3}">Switch To View3</Button>
        </StackPanel>
    </Grid>

鉴于上述情况，每当 CurrentViewModel 属性发生变化时，将根据 DataTemplate 资源选择视图，并设置 Window 的 DataContext MainViewModel.

主 ViewModel 如下所示：

 public class MainViewModel : ViewModelBase
    {
        //add instances to all the ViewModels you want to switch between here, and add templates for them in your resources specifying the x:type and the view or data template to be used
        public ObservableCollection<ViewModelBase> ViewModels { get; set; } = new ObservableCollection<ViewModelBase>();

        private ViewModelBase _currentViewModel;

        public ViewModelBase CurrentViewModel {
            get { return _currentViewModel; }
            set { SetField(ref _currentViewModel, value); }
        }

        private ICommand _nextViewModel;
        public ICommand NextViewModel
        {
            get
            {
                return _nextViewModel = _nextViewModel ?? new RelayCommand(p =>
                  {
                      CurrentViewModel = ViewModels[ViewModels.IndexOf(CurrentViewModel) +1];
                  }, p =>
                  {
                      return ViewModels.IndexOf(CurrentViewModel) + 1 != ViewModels.Count && CurrentViewModel != null;
                  });
            }
        }

        public ICommand _prevViewModel;
        public ICommand PrevViewModel
        {
            get
            {
                return _prevViewModel = _prevViewModel ?? new RelayCommand(p =>
                {
                    CurrentViewModel = ViewModels[ViewModels.IndexOf(CurrentViewModel) - 1];
                }, p =>
                {
                    return ViewModels.IndexOf(CurrentViewModel) != 0 && CurrentViewModel!=null;
                });
            }
        }

        private ICommand _switchToViewModel;
        public ICommand SwitchToViewModel
        {
            get
            {
               return _switchToViewModel = _switchToViewModel ?? new RelayCommand(p =>
                {
                    CurrentViewModel = this.ViewModels.FirstOrDefault(vm=>vm.GetType()==p as Type);
                }, p =>
                {
                    return this.ViewModels.FirstOrDefault(vm => vm.GetType() != p as Type) != null;
                });
            }
        }
    }

结果看起来像