C# 如何在WPF应用程序中的页面之间切换？

我正在尝试创建一个WPF应用程序，它显示一个登录视图，成功登录后，将显示第一、第二和第三页（类似于向导）。包括登录视图在内的每个“页面”都有其各自的

ViewModel

。我有一个

main window.xaml

，其中包含四个

UserControls

，其中一个在任何给定状态下都可见

我在处理可见性的编排方面遇到了问题。对我来说最有意义的是，

MainWindowViewModel

是负责跟踪当前可见的

UserControl

的工具，但我似乎无法让代码正常工作

我将只显示

main窗口

和

LoginView

的相关文件，以简化操作

main window.xaml

<Grid>
    <local:LoginView Visibility="{Not sure what to bind to here}" />
    <local:PageOne Visibility="{Not sure what to bind to here}" />
    <local:PageTwo Visibility="{Not sure what to bind to here}" />
    <local:PageThree Visibility="{Not sure what to bind to here}" />
</Grid>

<UserControl x:Class="MyProject.View.LoginView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:MyProject.View"
             mc:Ignorable="d" 
             d:DesignHeight="800" d:DesignWidth="1200">

    <Grid>
      <!-- UI Layout stuff here -->
    </Grid>
</UserControl>

<Window>
  <Window.DataContext>
    <MainViewModel x:Key="MainViewModel" />
  </Window.DataContext>
  <Window.Resources>
    <!-- 
        The templates for the view of each page model.
        Can be moved to dedicated files.
    -->  
    <DataTemplate DataType="{x:Type LoginViewModel}">
      <Border Background="Coral">

        <!-- UserControl -->
        <local:LoginView />
      </Border>
    </DataTemplate>

    <DataTemplate DataType="{x:Type PageOneViewModel}">
      <Border Background="Red">
        <local:PageOne />
      </Border>
    </DataTemplate>    

    <DataTemplate DataType="{x:Type PageTwoViewModel}">
      <Border Background="DeepSkyBlue">
        <TextBox Text="{Binding PageTitle}" />
      </Border>
    </DataTemplate>    
  </Window.Resources>


<StackPanel>
    <Button Content="Load Login Page"
            Command="{Binding SelectPageFromIndexCommand}"
            CommandParameter="0" />
    <Button Content="Load Page One"
            Command="{Binding SelectPageFromIndexCommand}"
            CommandParameter="1" />
    <Button Content="Load Next Page"
            Command="{Binding SelectNextPageCommand}" />

    <!-- The actual page control -->
    <ContentControl Content="{Binding SelectedPage}" />
  </StackPanel>
</Window>

MainWindowViewModel.cs

public partial class MainWindow : Window
{        
    public MainWindow()
    {
        InitializeComponent();
        DataContext = new MainWindowViewModel();
    }     
}

public partial class Login : UserControl
{
    public Login()
    {
        InitializeComponent();
        DataContext = new LoginViewModel();
    }
}

public class LoginViewModel : BaseViewModel
{
    public ICommand ConnectCommand { get; }
    public ICommand WindowClosingCommand { get; }

    public LoginViewModel()
    {
        ConnectCommand = new ConnectCommand(this);
        WindowClosingCommand = new WindowClosingCommand(this);
    }

    public string UserName { get; set; }
}

class MainViewModel : INotifyPropertyChanged
{
  public MainViewModel()
  {
    this.Pages = new ObservableCollection<IPageViewModel>() 
    {
      new LoginViewModel(), 
      new PageOneViewModel(), 
      new PageTwoViewModel()
    };

    // Show startup page
    this.SelectedPage = this.Pages.First();
  }

  // Define the Execute and CanExecute delegates for the command
  // and pass them to the constructor
  public ICommand SelectPageFromIndexCommand => new SelectPageCommand(
    param => this.SelectedPage = this.Pages.ElementAt(int.Parse(param as string)),
    param => int.TryParse(param as string, out int index));

  // Define the Execute and CanExecute delegates for the command
  // and pass them to the constructor
  public ICommand SelectNextPageCommand => new SelectPageCommand(
    param => this.SelectedPage = this.Pages.ElementAt(this.Pages.IndexOf(this.SelectedPage) + 1),
    param => this.Pages.IndexOf(this.SelectedPage) + 1 < this.Pages.Count);

  private IPageViewModel selectedPage;    
  public IPageViewModel SelectedPage
  {
    get => this.selectedPage;
    set
    {
      if (object.Equals(value, this.selectedPage))
      {
        return;
      }

      this.selectedPage = value;
      OnPropertyChanged();
    }
  }

  private ObservableCollection<IPageViewModel> pages;    
  public ObservableCollection<IPageViewModel> Pages
  {
    get => this.pages;
    set
    {
      if (object.Equals(value, this.pages))
      {
        return;
      }

      this.pages = value;
      OnPropertyChanged();
    }
  }

  public event PropertyChangedEventHandler PropertyChanged;    
  protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
  {
    this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
  }
}

class SelectPageCommand : ICommand
{
  public SelectPageCommand(Action<object> executeDelegate, Predicate<object> canExecuteDelegate)
  {
    this.ExecuteDelegate = executeDelegate;
    this.CanExecuteDelegate = canExecuteDelegate;
  }

  private Predicate<object> CanExecuteDelegate { get; }
  private Action<object> ExecuteDelegate { get; }

  #region Implementation of ICommand

  public bool CanExecute(object parameter) => this.CanExecuteDelegate?.Invoke(parameter) ?? false;

  public void Execute(object parameter) => this.ExecuteDelegate?.Invoke(parameter);

  public event EventHandler CanExecuteChanged
  {
    add => CommandManager.RequerySuggested += value;
    remove => CommandManager.RequerySuggested -= value;
  }

  #endregion
}

// Base type for all pages
interface IPageViewModel : INotifyPropertyChanged
{
  public string PageTitle { get; set; }
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class LoginViewModel : BaseViewModel
{
  // Implementation
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class PageOneViewModel : IPageViewModel 
{    
  // Implementation
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class PageTwoViewModel : IPageViewModel 
{    
  // Implementation
}

公共类MainWindowViewModel:BaseViewModel { 公共ICommand WindowClosingCommand{get；}

    public MainWindowViewModel()
    {
        WindowClosingCommand = new WindowClosingCommand(this);
    }
}

LoginView.xaml

<Grid>
    <local:LoginView Visibility="{Not sure what to bind to here}" />
    <local:PageOne Visibility="{Not sure what to bind to here}" />
    <local:PageTwo Visibility="{Not sure what to bind to here}" />
    <local:PageThree Visibility="{Not sure what to bind to here}" />
</Grid>

<UserControl x:Class="MyProject.View.LoginView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:MyProject.View"
             mc:Ignorable="d" 
             d:DesignHeight="800" d:DesignWidth="1200">

    <Grid>
      <!-- UI Layout stuff here -->
    </Grid>
</UserControl>

<Window>
  <Window.DataContext>
    <MainViewModel x:Key="MainViewModel" />
  </Window.DataContext>
  <Window.Resources>
    <!-- 
        The templates for the view of each page model.
        Can be moved to dedicated files.
    -->  
    <DataTemplate DataType="{x:Type LoginViewModel}">
      <Border Background="Coral">

        <!-- UserControl -->
        <local:LoginView />
      </Border>
    </DataTemplate>

    <DataTemplate DataType="{x:Type PageOneViewModel}">
      <Border Background="Red">
        <local:PageOne />
      </Border>
    </DataTemplate>    

    <DataTemplate DataType="{x:Type PageTwoViewModel}">
      <Border Background="DeepSkyBlue">
        <TextBox Text="{Binding PageTitle}" />
      </Border>
    </DataTemplate>    
  </Window.Resources>


<StackPanel>
    <Button Content="Load Login Page"
            Command="{Binding SelectPageFromIndexCommand}"
            CommandParameter="0" />
    <Button Content="Load Page One"
            Command="{Binding SelectPageFromIndexCommand}"
            CommandParameter="1" />
    <Button Content="Load Next Page"
            Command="{Binding SelectNextPageCommand}" />

    <!-- The actual page control -->
    <ContentControl Content="{Binding SelectedPage}" />
  </StackPanel>
</Window>

LoginViewModel.cs

public partial class MainWindow : Window
{        
    public MainWindow()
    {
        InitializeComponent();
        DataContext = new MainWindowViewModel();
    }     
}

public partial class Login : UserControl
{
    public Login()
    {
        InitializeComponent();
        DataContext = new LoginViewModel();
    }
}

public class LoginViewModel : BaseViewModel
{
    public ICommand ConnectCommand { get; }
    public ICommand WindowClosingCommand { get; }

    public LoginViewModel()
    {
        ConnectCommand = new ConnectCommand(this);
        WindowClosingCommand = new WindowClosingCommand(this);
    }

    public string UserName { get; set; }
}

class MainViewModel : INotifyPropertyChanged
{
  public MainViewModel()
  {
    this.Pages = new ObservableCollection<IPageViewModel>() 
    {
      new LoginViewModel(), 
      new PageOneViewModel(), 
      new PageTwoViewModel()
    };

    // Show startup page
    this.SelectedPage = this.Pages.First();
  }

  // Define the Execute and CanExecute delegates for the command
  // and pass them to the constructor
  public ICommand SelectPageFromIndexCommand => new SelectPageCommand(
    param => this.SelectedPage = this.Pages.ElementAt(int.Parse(param as string)),
    param => int.TryParse(param as string, out int index));

  // Define the Execute and CanExecute delegates for the command
  // and pass them to the constructor
  public ICommand SelectNextPageCommand => new SelectPageCommand(
    param => this.SelectedPage = this.Pages.ElementAt(this.Pages.IndexOf(this.SelectedPage) + 1),
    param => this.Pages.IndexOf(this.SelectedPage) + 1 < this.Pages.Count);

  private IPageViewModel selectedPage;    
  public IPageViewModel SelectedPage
  {
    get => this.selectedPage;
    set
    {
      if (object.Equals(value, this.selectedPage))
      {
        return;
      }

      this.selectedPage = value;
      OnPropertyChanged();
    }
  }

  private ObservableCollection<IPageViewModel> pages;    
  public ObservableCollection<IPageViewModel> Pages
  {
    get => this.pages;
    set
    {
      if (object.Equals(value, this.pages))
      {
        return;
      }

      this.pages = value;
      OnPropertyChanged();
    }
  }

  public event PropertyChangedEventHandler PropertyChanged;    
  protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
  {
    this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
  }
}

class SelectPageCommand : ICommand
{
  public SelectPageCommand(Action<object> executeDelegate, Predicate<object> canExecuteDelegate)
  {
    this.ExecuteDelegate = executeDelegate;
    this.CanExecuteDelegate = canExecuteDelegate;
  }

  private Predicate<object> CanExecuteDelegate { get; }
  private Action<object> ExecuteDelegate { get; }

  #region Implementation of ICommand

  public bool CanExecute(object parameter) => this.CanExecuteDelegate?.Invoke(parameter) ?? false;

  public void Execute(object parameter) => this.ExecuteDelegate?.Invoke(parameter);

  public event EventHandler CanExecuteChanged
  {
    add => CommandManager.RequerySuggested += value;
    remove => CommandManager.RequerySuggested -= value;
  }

  #endregion
}

// Base type for all pages
interface IPageViewModel : INotifyPropertyChanged
{
  public string PageTitle { get; set; }
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class LoginViewModel : BaseViewModel
{
  // Implementation
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class PageOneViewModel : IPageViewModel 
{    
  // Implementation
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class PageTwoViewModel : IPageViewModel 
{    
  // Implementation
}

正如您所看到的，我希望避免在代码隐藏文件

.xaml.cs

中放入大量逻辑，因为这是最佳实践，我有一个

ViewModel

文件，它的

.xaml

文件

public PageType CurrentPage;

public enum PageType
{
    Login, PageOne, PageTwo, PageThree
}

public Visibility LoginVisibility
{
    get { (CurrentPage == PageType.Login) ? Visibility.Visible : Visibility.Collapsed }
}

// Repeat for each of the other three pages

然后根据是否在每页上单击了“下一步”或“上一步”按钮，我会正确设置

CurrentPage

字段

但是，如果我们回到我的

MainWindow.xaml

，我不能只做：

<local:LoginView Visibility="{Binding LoginVisibility}" />

因为

LoginVisibility

不存在于

LoginViewModel

中，而这正是用户控件的数据上下文。将该字段放在那里是不对的，因为所有

ViewModels

都需要知道自己的可见性状态，并以某种方式将其传达到

main窗口

---

基本上，我对如何在应用程序中的页面之间切换感到困惑和不确定。任何帮助或指导都将不胜感激。

您可以在主窗口资源中创建数据模板，并将适当的数据模板绑定到控件模板，而不是绑定可见性（在您希望显示它的网格内）基于枚举更改

下面是一个粗略的想法

在mainwindow.xaml中

 <Window.Resources>
    <ResourceDictionary>
        <DataTemplate x:Key="DTLoginView">
            <local:LoginView />
        </DataTemplate>
        <DataTemplate x:Key="DTPageOne">
            <local:PageOne />
        </DataTemplate>
    </ResourceDictionary>
</Window.Resources>

在主窗口的XAML中。（在其中有网格）

如果您查看上面的xaml代码，我将datatrigger绑定的值设置为“0”“1”，因为枚举应该有0,1,2,3等等。但是，您也可以直接将枚举绑定为值。进行一些搜索，您可以轻松找到答案

当前页面的属性（枚举值）应该由某些逻辑（由您实现）设置。一旦设置完成，它将自动触发对xaml的通知

---

希望这能对您有所帮助。

与使用

框架相比，最简单、最轻量级的方法是为每个页面创建一个视图模型。然后创建一个包含所有页面并管理其选择的主视图模型。
ContentControl
将使用分配给e
ContentControl.ContentTemplate
属性，或者在多页场景中，通过只定义
DataTemplate.DataType
而不定义
键
属性，将
DataTemplateSelector
分配给
ContentControl.ContentTemplateSelector
或隐式模板：

景色
main window.xaml

<Grid>
    <local:LoginView Visibility="{Not sure what to bind to here}" />
    <local:PageOne Visibility="{Not sure what to bind to here}" />
    <local:PageTwo Visibility="{Not sure what to bind to here}" />
    <local:PageThree Visibility="{Not sure what to bind to here}" />
</Grid>

<UserControl x:Class="MyProject.View.LoginView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:MyProject.View"
             mc:Ignorable="d" 
             d:DesignHeight="800" d:DesignWidth="1200">

    <Grid>
      <!-- UI Layout stuff here -->
    </Grid>
</UserControl>

<Window>
  <Window.DataContext>
    <MainViewModel x:Key="MainViewModel" />
  </Window.DataContext>
  <Window.Resources>
    <!-- 
        The templates for the view of each page model.
        Can be moved to dedicated files.
    -->  
    <DataTemplate DataType="{x:Type LoginViewModel}">
      <Border Background="Coral">

        <!-- UserControl -->
        <local:LoginView />
      </Border>
    </DataTemplate>

    <DataTemplate DataType="{x:Type PageOneViewModel}">
      <Border Background="Red">
        <local:PageOne />
      </Border>
    </DataTemplate>    

    <DataTemplate DataType="{x:Type PageTwoViewModel}">
      <Border Background="DeepSkyBlue">
        <TextBox Text="{Binding PageTitle}" />
      </Border>
    </DataTemplate>    
  </Window.Resources>


<StackPanel>
    <Button Content="Load Login Page"
            Command="{Binding SelectPageFromIndexCommand}"
            CommandParameter="0" />
    <Button Content="Load Page One"
            Command="{Binding SelectPageFromIndexCommand}"
            CommandParameter="1" />
    <Button Content="Load Next Page"
            Command="{Binding SelectNextPageCommand}" />

    <!-- The actual page control -->
    <ContentControl Content="{Binding SelectedPage}" />
  </StackPanel>
</Window>

LoginViewModel.cs

public partial class MainWindow : Window
{        
    public MainWindow()
    {
        InitializeComponent();
        DataContext = new MainWindowViewModel();
    }     
}

public partial class Login : UserControl
{
    public Login()
    {
        InitializeComponent();
        DataContext = new LoginViewModel();
    }
}

public class LoginViewModel : BaseViewModel
{
    public ICommand ConnectCommand { get; }
    public ICommand WindowClosingCommand { get; }

    public LoginViewModel()
    {
        ConnectCommand = new ConnectCommand(this);
        WindowClosingCommand = new WindowClosingCommand(this);
    }

    public string UserName { get; set; }
}

class MainViewModel : INotifyPropertyChanged
{
  public MainViewModel()
  {
    this.Pages = new ObservableCollection<IPageViewModel>() 
    {
      new LoginViewModel(), 
      new PageOneViewModel(), 
      new PageTwoViewModel()
    };

    // Show startup page
    this.SelectedPage = this.Pages.First();
  }

  // Define the Execute and CanExecute delegates for the command
  // and pass them to the constructor
  public ICommand SelectPageFromIndexCommand => new SelectPageCommand(
    param => this.SelectedPage = this.Pages.ElementAt(int.Parse(param as string)),
    param => int.TryParse(param as string, out int index));

  // Define the Execute and CanExecute delegates for the command
  // and pass them to the constructor
  public ICommand SelectNextPageCommand => new SelectPageCommand(
    param => this.SelectedPage = this.Pages.ElementAt(this.Pages.IndexOf(this.SelectedPage) + 1),
    param => this.Pages.IndexOf(this.SelectedPage) + 1 < this.Pages.Count);

  private IPageViewModel selectedPage;    
  public IPageViewModel SelectedPage
  {
    get => this.selectedPage;
    set
    {
      if (object.Equals(value, this.selectedPage))
      {
        return;
      }

      this.selectedPage = value;
      OnPropertyChanged();
    }
  }

  private ObservableCollection<IPageViewModel> pages;    
  public ObservableCollection<IPageViewModel> Pages
  {
    get => this.pages;
    set
    {
      if (object.Equals(value, this.pages))
      {
        return;
      }

      this.pages = value;
      OnPropertyChanged();
    }
  }

  public event PropertyChangedEventHandler PropertyChanged;    
  protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
  {
    this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
  }
}

class SelectPageCommand : ICommand
{
  public SelectPageCommand(Action<object> executeDelegate, Predicate<object> canExecuteDelegate)
  {
    this.ExecuteDelegate = executeDelegate;
    this.CanExecuteDelegate = canExecuteDelegate;
  }

  private Predicate<object> CanExecuteDelegate { get; }
  private Action<object> ExecuteDelegate { get; }

  #region Implementation of ICommand

  public bool CanExecute(object parameter) => this.CanExecuteDelegate?.Invoke(parameter) ?? false;

  public void Execute(object parameter) => this.ExecuteDelegate?.Invoke(parameter);

  public event EventHandler CanExecuteChanged
  {
    add => CommandManager.RequerySuggested += value;
    remove => CommandManager.RequerySuggested -= value;
  }

  #endregion
}

// Base type for all pages
interface IPageViewModel : INotifyPropertyChanged
{
  public string PageTitle { get; set; }
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class LoginViewModel : BaseViewModel
{
  // Implementation
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class PageOneViewModel : IPageViewModel 
{    
  // Implementation
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class PageTwoViewModel : IPageViewModel 
{    
  // Implementation
}

PageOneViewModel.cs

public partial class MainWindow : Window
{        
    public MainWindow()
    {
        InitializeComponent();
        DataContext = new MainWindowViewModel();
    }     
}

public partial class Login : UserControl
{
    public Login()
    {
        InitializeComponent();
        DataContext = new LoginViewModel();
    }
}

public class LoginViewModel : BaseViewModel
{
    public ICommand ConnectCommand { get; }
    public ICommand WindowClosingCommand { get; }

    public LoginViewModel()
    {
        ConnectCommand = new ConnectCommand(this);
        WindowClosingCommand = new WindowClosingCommand(this);
    }

    public string UserName { get; set; }
}

class MainViewModel : INotifyPropertyChanged
{
  public MainViewModel()
  {
    this.Pages = new ObservableCollection<IPageViewModel>() 
    {
      new LoginViewModel(), 
      new PageOneViewModel(), 
      new PageTwoViewModel()
    };

    // Show startup page
    this.SelectedPage = this.Pages.First();
  }

  // Define the Execute and CanExecute delegates for the command
  // and pass them to the constructor
  public ICommand SelectPageFromIndexCommand => new SelectPageCommand(
    param => this.SelectedPage = this.Pages.ElementAt(int.Parse(param as string)),
    param => int.TryParse(param as string, out int index));

  // Define the Execute and CanExecute delegates for the command
  // and pass them to the constructor
  public ICommand SelectNextPageCommand => new SelectPageCommand(
    param => this.SelectedPage = this.Pages.ElementAt(this.Pages.IndexOf(this.SelectedPage) + 1),
    param => this.Pages.IndexOf(this.SelectedPage) + 1 < this.Pages.Count);

  private IPageViewModel selectedPage;    
  public IPageViewModel SelectedPage
  {
    get => this.selectedPage;
    set
    {
      if (object.Equals(value, this.selectedPage))
      {
        return;
      }

      this.selectedPage = value;
      OnPropertyChanged();
    }
  }

  private ObservableCollection<IPageViewModel> pages;    
  public ObservableCollection<IPageViewModel> Pages
  {
    get => this.pages;
    set
    {
      if (object.Equals(value, this.pages))
      {
        return;
      }

      this.pages = value;
      OnPropertyChanged();
    }
  }

  public event PropertyChangedEventHandler PropertyChanged;    
  protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
  {
    this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
  }
}

class SelectPageCommand : ICommand
{
  public SelectPageCommand(Action<object> executeDelegate, Predicate<object> canExecuteDelegate)
  {
    this.ExecuteDelegate = executeDelegate;
    this.CanExecuteDelegate = canExecuteDelegate;
  }

  private Predicate<object> CanExecuteDelegate { get; }
  private Action<object> ExecuteDelegate { get; }

  #region Implementation of ICommand

  public bool CanExecute(object parameter) => this.CanExecuteDelegate?.Invoke(parameter) ?? false;

  public void Execute(object parameter) => this.ExecuteDelegate?.Invoke(parameter);

  public event EventHandler CanExecuteChanged
  {
    add => CommandManager.RequerySuggested += value;
    remove => CommandManager.RequerySuggested -= value;
  }

  #endregion
}

// Base type for all pages
interface IPageViewModel : INotifyPropertyChanged
{
  public string PageTitle { get; set; }
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class LoginViewModel : BaseViewModel
{
  // Implementation
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class PageOneViewModel : IPageViewModel 
{    
  // Implementation
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class PageTwoViewModel : IPageViewModel 
{    
  // Implementation
}

PageTwoViewModel.cs

public partial class MainWindow : Window
{        
    public MainWindow()
    {
        InitializeComponent();
        DataContext = new MainWindowViewModel();
    }     
}

public partial class Login : UserControl
{
    public Login()
    {
        InitializeComponent();
        DataContext = new LoginViewModel();
    }
}

public class LoginViewModel : BaseViewModel
{
    public ICommand ConnectCommand { get; }
    public ICommand WindowClosingCommand { get; }

    public LoginViewModel()
    {
        ConnectCommand = new ConnectCommand(this);
        WindowClosingCommand = new WindowClosingCommand(this);
    }

    public string UserName { get; set; }
}

class MainViewModel : INotifyPropertyChanged
{
  public MainViewModel()
  {
    this.Pages = new ObservableCollection<IPageViewModel>() 
    {
      new LoginViewModel(), 
      new PageOneViewModel(), 
      new PageTwoViewModel()
    };

    // Show startup page
    this.SelectedPage = this.Pages.First();
  }

  // Define the Execute and CanExecute delegates for the command
  // and pass them to the constructor
  public ICommand SelectPageFromIndexCommand => new SelectPageCommand(
    param => this.SelectedPage = this.Pages.ElementAt(int.Parse(param as string)),
    param => int.TryParse(param as string, out int index));

  // Define the Execute and CanExecute delegates for the command
  // and pass them to the constructor
  public ICommand SelectNextPageCommand => new SelectPageCommand(
    param => this.SelectedPage = this.Pages.ElementAt(this.Pages.IndexOf(this.SelectedPage) + 1),
    param => this.Pages.IndexOf(this.SelectedPage) + 1 < this.Pages.Count);

  private IPageViewModel selectedPage;    
  public IPageViewModel SelectedPage
  {
    get => this.selectedPage;
    set
    {
      if (object.Equals(value, this.selectedPage))
      {
        return;
      }

      this.selectedPage = value;
      OnPropertyChanged();
    }
  }

  private ObservableCollection<IPageViewModel> pages;    
  public ObservableCollection<IPageViewModel> Pages
  {
    get => this.pages;
    set
    {
      if (object.Equals(value, this.pages))
      {
        return;
      }

      this.pages = value;
      OnPropertyChanged();
    }
  }

  public event PropertyChangedEventHandler PropertyChanged;    
  protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
  {
    this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
  }
}

class SelectPageCommand : ICommand
{
  public SelectPageCommand(Action<object> executeDelegate, Predicate<object> canExecuteDelegate)
  {
    this.ExecuteDelegate = executeDelegate;
    this.CanExecuteDelegate = canExecuteDelegate;
  }

  private Predicate<object> CanExecuteDelegate { get; }
  private Action<object> ExecuteDelegate { get; }

  #region Implementation of ICommand

  public bool CanExecute(object parameter) => this.CanExecuteDelegate?.Invoke(parameter) ?? false;

  public void Execute(object parameter) => this.ExecuteDelegate?.Invoke(parameter);

  public event EventHandler CanExecuteChanged
  {
    add => CommandManager.RequerySuggested += value;
    remove => CommandManager.RequerySuggested -= value;
  }

  #endregion
}

// Base type for all pages
interface IPageViewModel : INotifyPropertyChanged
{
  public string PageTitle { get; set; }
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class LoginViewModel : BaseViewModel
{
  // Implementation
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class PageOneViewModel : IPageViewModel 
{    
  // Implementation
}

// BaseViewModel implementation. 
// Consider to introduce dedicated abstract class Page which implements IPageViewModel 
class PageTwoViewModel : IPageViewModel 
{    
  // Implementation
}

在VMMS中使用“代码>内容控制< /代码>。在MaVIM上创建属性以存储当前VM。一旦将内容控件绑定到当前视图模型，就不需要EnUM。也不需要处理可视性。通常我会先推荐VIEWMIDE。向导是我考虑的少数需求之一。一个框架中的g个页面。您可以轻松地在一个框架内前后导航。每个页面都保留其视图状态。在di容器或资源或中介对象中放置对viewmodels的引用，并使页面从中获取其datacontext。如果需要重置，请再次实例化页面并替换这些实例。或者您可以uld首先进入viewmodel。你有用户控件。你有viewmodels。你所需要做的就是告诉它哪个uc用于哪个vm，谢谢你的评论。我想我在想你在这里要做什么。但是，页面模型（例如
PageA.cs
和
PageB.cs
）与用户控件中的UI有什么关系（
PageOne.xaml
）我设计的？我调整了代码示例。您现在可以复制和粘贴代码，它将运行。只需添加视图模型的实现，并添加视图实现，以便可以实例化
DataTemplate
中定义的对象。基本思想是将页面视图包装到
DataTemplate
它的
DataType
设置为作为数据源的模型类型，即包装视图的
DataContext
。我还添加了一个
SelectNextPageCommand
，并在视图中添加了一个相应的
按钮
，以显示其基本原理和简单性。您现在可以通过索引和下一页进行选择。只需在e所有页面模型都派生自一个公共类型。Thia common type是包含所有页面的集合的通用参数。还要确保公共基类型的每个实现