WPF MVVM从同一等级级别浏览视图

Question

我正在尝试制作一个主要用于学习MVVM的小程序。它是一个小书库。

我有4个视图（和4个viewmodels）。 MainWindow是父视图，其中我在内容控件中显示其他3视图。

其他3个子视图是HomeView，BookManagingView，ReaderManagingView。

在HomeView中，我显示2个ListViews（一个带有阅读器，一个带有书本），另外两个视图中我编辑/添加书籍或阅读器。

在我的HomeView中，我也有2个按钮。当我点击我想从HomeView切换到BookManagingView或ReaderManagingView的按钮时。

如果我试图从MainWindow切换到任何视图，它的工作原理。

我想要做的是从HomeView切换到BookManagingView或ReaderManagingView。我怎么能做到这一点？

主窗口：

<Grid> 
    <ContentControl Content="{Binding CurrentView}" Height="340" Width="500" /> 
    <Button x:Name="btnHomeView" Content="Home" Command="{Binding ChangeViewToHomeView, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" Margin="16,70,0,0" VerticalAlignment="Top" Width="75"/> 
    <Button x:Name="btnBookManagingView" Content="Reader Options" Command="{Binding ChangeViewToReaderManagView,UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" Margin="96,70,0,0" VerticalAlignment="Top" Width="92"/> 
    <Button x:Name="btnReaderManagingView" Content="Books Options" Command="{Binding ChangeViewToBookManagView,UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" Margin="193,70,0,0" VerticalAlignment="Top" Width="92"/> 
</Grid> 

MainWindowVM：

public class MainWindowViewModel : ViewModelBase 
{ 
    private object currentView; 
    private HomeViewModel homeVM; 
    private ReaderManagingViewModel readerManagingVM; 
    private BookManagingViewModel bookManagingVM; 


    public MainWindowViewModel() 
    { 
     homeVM = new HomeViewModel(); 
     readerManagingVM = new ReaderManagingViewModel(); 
     bookManagingVM = new BookManagingViewModel(); 
     CurrentView = homeVM; 

     ChangeViewToHomeView = new DefCommand(DisplayHomeView); 
     ChangeViewToReaderManagView = new DefCommand(DisplayReaderManagingView); 
     ChangeViewToBookManagView = new DefCommand(DisplayBookManagingView); 
    } 

    public DefCommand ChangeViewToHomeView { get; private set; } 
    public DefCommand ChangeViewToReaderManagView { get; private set; } 
    public DefCommand ChangeViewToBookManagView { get; private set; } 


    public object CurrentView 
    { 
     get { return currentView; } 
     set { currentView = value; RaisePropertyChanged(); } 
    } 

    public void DisplayHomeView() 
    { 
     CurrentView = homeVM; 
    } 

    public void DisplayReaderManagingView() 
    { 
     CurrentView = readerManagingVM; 
    } 

    public void DisplayBookManagingView() 
    { 
     CurrentView = bookManagingVM; 
    } 

HomeView：

<Grid> 
    <ListView x:Name="listviewReaders" ItemsSource="{Binding ReadersList}" SelectedItem="{Binding SelectedReader, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Width="160" Margin="25,23,315,40"> 

...

<ListView x:Name="listviewBooks" ItemsSource="{Binding BookList, Mode=OneWay}" SelectedItem="{Binding SelectedBook, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Width="160" Margin="316,50,24,117"> 

...

<Button x:Name="btnEditReader" Command="{Binding EditReaderSwitch, UpdateSourceTrigger=PropertyChanged}" Content="EditR" HorizontalAlignment="Left" Margin="316,305,0,0" VerticalAlignment="Top" Width="74"/> 
    <Button x:Name="btnEditBook" Command="{Binding EditBookSwitch, UpdateSourceTrigger=PropertyChanged}" Content="EditB" HorizontalAlignment="Left" Margin="402,305,0,0" VerticalAlignment="Top" Width="74"/> 
</Grid> 

HomeVM：

private Reader selectedReader; 
    private Book selectedBook; 
    private BookListFilter selectedFilter; 

    private ObservableCollection<Book> bookList; 
    private ObservableCollection<Reader> readerList; 
    private IEnumerable<BookListFilter> bookLstItemSrc; 

    public HomeViewModel() 
    { 
     SelectedReader = new Reader(); 
     SelectedBook = new Book(); 
     SelectedFilter = BookListFilter.AllBooks; 

     BookDBDataContext rdb = new BookDBDataContext(); 

     ReadersList = new ObservableCollection<Reader>(rdb.Readers); 
     GetBookList(); 

     EditReaderSwitch = new DefCommand(EditReaderInfo); 
     EditBookSwitch = new DefCommand(EditBookInfo); 
    } 

    public DefCommand EditReaderSwitch { get; private set; } 
    public DefCommand EditBookSwitch { get; private set; } 
private void EditBookInfo() 
    { 
     var tmpBook = new BookManagingViewModel(this); 
     var tmpMwvm = new MainWindowViewModel(); 
     tmpMwvm.DisplayBookManagingView(); 
    } 

    private void EditReaderInfo() 
    { 
     var tmpReader = new ReaderManagingViewModel(this); 
     var tmpMwvm = new MainWindowViewModel(); 
     tmpMwvm.DisplayReaderManagingView(); 
    } 

书&读者ManagingViews有增加，从数据库中删除到/一堆文本框和按钮。

书&读者ManagingVM有添加方法/从数据库中删除以/（现在他们是空的，我会完成他们，如果我设法解决这个问题第一）

我试图从HomeView到导航Book/ReaderManagingView与EditBook/ReaderSwitch命令和EditBook/ReaderInfo（）方法，但它不起作用。

我在做什么错，我应该怎么做才能解决它？

对不起，很长的文章。

Answer 1

您需要设置现有MainWindowViewModel实例的CurrentView属性。现在你正在创建一个新的类的实例。

你可以注入HomeViewModel用MainWindowViewModel：

private readonly MainWindowViewModel _x; 
public HomeViewModel(MainWindowViewModel x) 
{ 
    _x = x; 
    SelectedReader = new Reader(); 
    ... 
} 

private void EditBookInfo() 
{ 
    _x.DisplayBookManagingView(); 
} 

MainWindowViewModel：

public MainWindowViewModel() 
{ 
    homeVM = new HomeViewModel(this); 
}