在WPF中使用MVVM進行視圖導航

Question

對WPF和MVVM的新增功能。 我試圖創建使用MVVM的登錄窗口，我成功創建。
這裏是Login.xmal代碼。

<Button x:Name="btnLogin" Content="Login" HorizontalAlignment="Left" Margin="51,0,0,10" 
      VerticalAlignment="Bottom" Width="124" Height="57" Grid.Column="1" 
      CommandParameter="{Binding ElementName=txtPassword}" 
      Command="{Binding LoginCommand}" 
      >   
    </Button> 

    <Button x:Name="btnClose" Content="Close" HorizontalAlignment="Left" Margin="180,0,0,10" 
     VerticalAlignment="Bottom" Width="124" Height="57" Grid.Column="1" Command="{Binding ExitCommand}"> 

    </Button> 

    <Label Content="User Name" Margin="10,74,0,0" VerticalAlignment="Top" Height="49" 
      VerticalContentAlignment="Center" Grid.Column="1" HorizontalAlignment="Left" Width="130"/> 

    <TextBox x:Name="txtUserName" HorizontalAlignment="Right" Height="49" Margin="0,74,10,0" 

      TextWrapping="Wrap" VerticalAlignment="Top" Width="185" 
      VerticalContentAlignment="Center" Grid.Column="1" FontSize="18"> 
     <TextBox.Text> 
      <Binding Path="Username" Mode="OneWayToSource"> 
       <Binding.ValidationRules> 
        <ExceptionValidationRule></ExceptionValidationRule> 
       </Binding.ValidationRules> 
      </Binding> 
     </TextBox.Text> 
    </TextBox> 

    <Label Content="Password" Margin="10,128,0,0" VerticalAlignment="Top" Height="49" 
      VerticalContentAlignment="Center" Grid.Column="1" HorizontalAlignment="Left" Width="130"/> 
    <PasswordBox x:Name="txtPassword" HorizontalAlignment="Right" 
      Height="49" Margin="0,128,10,0" 
      VerticalAlignment="Top" Width="185" 
     VerticalContentAlignment="Center" Grid.Column="1" FontSize="18"> 

    </PasswordBox> 

在這之後我已經創建了我實現INotifyPropertyChanged的的viewModeBase.cs類，這包括在LoginViewModel.cs ... 這裏是LoginViewModel.cs代碼

public class LoginViewModel : ViewModelBase 
{ 
    private string m_username; 
    public string Username 
    { 
     get { return m_username; } 
     set 
     { 
      m_username = value; 
      OnPropertyChanged("Username"); 

     } 
    } 

    private string m_password; 
    public string Password 
    { 
     get { return m_password; } 
     set 
     { 
      m_password = value; 
      OnPropertyChanged("Password"); 
     } 
    } 
    private DelegateCommand exitCommand; 

    public ICommand ExitCommand 
    { 
     get 
     { 
      if (exitCommand == null) 
      { 
       exitCommand =new DelegateCommand(Exit); 
      } 
      return exitCommand; 
     } 
    } 

    private void Exit() 
    { 
     Application.Current.Shutdown(); 
    } 

    public LoginViewModel() 
    { 

    } 

    private DelegateCommand<object> loginCommand; 
    public ICommand LoginCommand 
    { 
     get 
     { 
      if (loginCommand == null) 
      { 
       loginCommand = new DelegateCommand<object>(Login); 
      } 
      return loginCommand; 
     } 
    } 



    public void Login(object pPasswordBox) 
    { 
     try 
     { 
      if (string.IsNullOrEmpty(Username)) 
      { 
       MessageBox.Show("Username cannot be blank.");      
       return; 
      } 

      if (string.IsNullOrEmpty(((PasswordBox)pPasswordBox).Password)) 
      { 
       MessageBox.Show("Password cannot be blank.");     
       return; 
      } 

      dlUsers odlUsers = new dlUsers(); 
      bool lResult = odlUsers.UserAuthentication(clsGymManagment.ConnectionString, Username, 
       ((((PasswordBox)pPasswordBox).Password))); 
      if (lResult) 
      { 
       ///TODO: Need code to Hide Login Window and Open New XAML..... 
      } 
      else 
      { 
       MessageBox.Show("Username/Password is wrong.");     
      } 
     } 
     catch (Exception ex) 
     { 
      MessageBox.Show(ex.Message); 
     } 
    }   
} 

因爲我想隱藏LOGIN.XAML文件並打開UI.XAML文件..（UI.XAML您可以考慮使用任何XAML窗口。）... 如果您可以幫助我導航UserControl之間的用戶界面UI.XAML

Answer 1

您需要通過單獨的代碼塊控制登錄窗口，例如App.xaml.cs.設置app.xaml來調用代碼而不是顯示一個窗口。

讓App_Startup創建LoginViewModel，新建一個表單，將表單的數據上下文設置到您的ViewModel並顯示它。

窗體的更新將更新ViewModel，當它關閉時會將控制權返回給您的調用代碼。

Login.xaml.cs

private void btnOk_Click(object sender, RoutedEventArgs e) 
    { 
     if (anything incorrect) 
     { 
      MessageBox.Show("Enter a username and password"); 
     } 
     else 
      DialogResult = true; 
    } 

App.xaml.cs

Login.DataContext = LoginViewModel; 

if (Login.ShowDialog() ?? false) 
{ 
    //Check the LoginViewModel for a correct password. 
} 

Answer 2

幸運藏身，當你通過不同的頁面中移動內部的應用已寫入的顯示不同的控制能力您。見http://msdn.microsoft.com/en-us/library/ms750478.aspx。

導航窗口非常強大，可以非常容易地剝皮以提供非常完全不同的外觀。見http://alski.net/post/2012/01/13/WPF-Wizards-part-2-Glass.aspx