開幕WPF窗口MVVM和關閉它

Question

可能重複：
WPF MVVM Newbie - how should the ViewModel close the form?

我已搜索周圍計算器，我不認爲給出的答案適用於礦井或我可以」瞭解如何應用它們。

我有一個沼澤標準的MVVM WPF應用程序。 MVVM部分由一個RelayCommand類和一個ViewModelBase類以及一個擴展ViewModelBase的WorkspaceViewModel類組成。

我有兩個窗口，MainWindow和CustomMessageBox窗口（實際上向用戶提供一個問題和兩個答案）。我用這個代碼在主窗口打開CustomMessageBox（第二窗口）：

public ICommand BrowseFileFolderCommand 
    { 
     get 
     { 
      if (_browseFileFolderCommand == null) 
      { 
       _browseFileFolderCommand = new RelayCommand(o => 
        { 
         var messageViewModel = new MessageBoxViewModel("Add a Folder or File", "What do you wish to add, folder or file?", "Folder", "File"); 
         var choice = new CustomMessageBox() 
         { 
          DataContext = messageViewModel 
         }; 
         choice.ShowDialog(); 

         if (messageViewModel.CustomMessageBoxDialogResult == DialogResult.Yes) 
         { 
          switch (messageViewModel.ChosenEntity) 
          { 
           case SelectedAnswer.Answer1: 
            // Get folder shizz 
            break; 
           case SelectedAnswer.Answer2: 
            // Get file shizz 
            break; 
           default: 
            break; 
          } 
         } 
        }, null); 
      } 
      return _browseFileFolderCommand; 
     } 
    } 

一旦CustomMessageBox已經啓動，我不能與CloseCommand關閉它。當我嘗試調試CustomMessageBox的加載時，似乎所有的ICommands在我按下任何東西之前被觸發了？

的WorkspaceViewModel有CloseCommand：

#region CloseCommand 

    /// <summary> 
    /// Returns the command that, when invoked, attempts 
    /// to remove this workspace from the user interface. 
    /// </summary> 
    public ICommand CloseCommand 
    { 
     get 
     { 
      if (_closeCommand == null) 
       _closeCommand = new RelayCommand(param => this.OnRequestClose()); 

      return _closeCommand; 
     } 
    } 

    #endregion // CloseCommand 

    #region RequestClose [event] 

    /// <summary> 
    /// Raised when this workspace should be removed from the UI. 
    /// </summary> 
    public event EventHandler RequestClose; 

    void OnRequestClose() 
    { 
     EventHandler handler = this.RequestClose; 
     if (handler != null) 
      handler(this, EventArgs.Empty); 
    } 

    #endregion // RequestClose [event] 

有沒有人有什麼想法？我是否遺漏了任何關鍵的東西？

感謝，

Answer 1

我實際上並沒有將任何方法附加到事件處理程序，所以當調用事件處理程序時，沒有任何事情做，因爲代碼到了死衚衕，所以我更改了代碼，並附上了Close方法窗口視圖模型的事件處理程序：

messageViewModel.RequestClose += (s, e) => choice.Close(); 

下面是完整的代碼：

public ICommand BrowseFileFolderCommand 
{ 
    get 
    { 
     if (_browseFileFolderCommand == null) 
     { 
      _browseFileFolderCommand = new RelayCommand(() => 
       { 
        var messageViewModel = new MessageBoxViewModel("Add a Folder or File", "What do you wish to add, folder or file?", "Folder", "File"); 
        var choice = new CustomMessageBox() 
        { 
         DataContext = messageViewModel 
        }; 
        // Added this line 
        messageViewModel.RequestClose += (s, e) => choice.Close(); 
        choice.ShowDialog(); 

        if (messageViewModel.CustomMessageBoxDialogResult == DialogResult.Yes) 
        { 
         switch (messageViewModel.ChosenEntity) 
         { 
          case SelectedAnswer.Answer1: 
           // Get folder shizz 
           break; 
          case SelectedAnswer.Answer2: 
           // Get file shizz 
           break; 
          default: 
           break; 
         } 
        } 
       }, null); 
     } 
     return _browseFileFolderCommand; 
    } 
} 

謝謝大家幫助我得到的答案，這只是爲了澄清對我特別的問題。

謝謝。

Answer 2

當我需要做到這一點，我叫下面的代碼行從我Command.Execute邏輯：

App.Current.Windows.Cast<Window>().Where(win => win is CustomMessageBox).FirstOrDefault().Close(); 

我希望這有助於。