MVVM中的列表視圖複選框的選定項目WPF

Question

我想在視圖模型中傳遞列表視圖複選框的選定項目，稍後我將使用進一步的過程來存儲在數據庫中。

在FormWeek.xaml守則

守則FormWeek.xaml.cs

private void SelectDays(object sender, SelectionChangedEventArgs e) 
     { 
      (this.DataContext as TaskExecDefinitionViewModel).OnCheckBoxCommand(checkedListView.SelectedItems,true); 

     } 

我的視圖模型TaskWeek.cs如下

//聲明

private RelayCommand<object> _checkBoxCommand; 

public ObservableCollection<string> CollectionOfDays { get; set; } 
public ObservableCollection<string> SelectedItems { get; set; } 

public RelayCommand<object> CheckBoxCommand 
     { 
      get 
      {    
       if (_checkBoxCommand == null) 
       { 
        _checkBoxCommand = new RelayCommand<object>((args) => OnCheckBoxCommand(args,true)); 
        // _checkBoxCommand = new RelayCommand(() => OnCheckBoxCommand(object args)); 
       } 
       return _checkBoxCommand; 
      } 
     } 

// Con structor

CollectionOfDays = new ObservableCollection<string>(); 

//方法

private void GetWeekDays() 
     { 
      try 
      { 
       Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() => 
        { 

         CollectionOfDays.Add("Saturday"); 
         CollectionOfDays.Add("Sunday"); 
         CollectionOfDays.Add("Monday"); 
         CollectionOfDays.Add("Tuesday"); 
         CollectionOfDays.Add("Wednesday"); 
         CollectionOfDays.Add("Thursday"); 
         CollectionOfDays.Add("Friday");       
        })); 
      } 
      catch(Exception Ex) 
      { 
       MessageBox.Show(Ex.Message, "TaskWeek:GetWeekDays"); 
      } 
     } 

public void OnCheckBoxCommand(object obj, bool _direction) 
     { 
      try 
      { 

       if (SelectedItems == null) 
        SelectedItems = new ObservableCollection<string>(); 

       if (obj != null) 
       { 
        SelectedItems.Clear(); 
        StringBuilder items = new StringBuilder(); 


        if (_direction) 
        { 
         foreach (string item in CollectionOfDays) 
         { 

          items.AppendFormat(item + ","); 
         } 
        } 

        MessageBox.Show(items.ToString()); 
        } 
       else 
        SelectedItems.Clear();    

      } 
      catch (Exception ex) 
      { 
       MessageBox.Show(ex.Message, "TaskDefinition:OnCheckBoxCommand"); 
      } 
     } 

及以下按鈕點擊commond保存數據。

<Button Grid.Column="2" Grid.Row="2" Content="Save" HorizontalAlignment="Center" VerticalAlignment="Bottom" 
       Command="{Binding InsertExecDefCommand}" Margin="5" > 

現在我的要求是通過選定的列表視圖項目通過命令對象查看模型。我已通過SelectionChanged事件做過FormWeek.xam.cs這個使用下面的代碼作爲

private void OnSelectedItems(object sender, RoutedEventArgs e) 
     { 
      StringBuilder items = new StringBuilder(); 
      foreach (string item in checkedListView.SelectedItems) 
      { 
       items.AppendFormat(item + ","); 
      } 
      string AllDays= items.ToString(); 
     } 

但是請讓我知道如何實現通過MVVM這個邏輯。如何在我的視圖模型中獲取選定項目TaskWeek.cs

之後R & D和谷歌我通過RelayCommand完成了chages。在OnCheckBoxCommand方法中，foreach語句是錯誤的，它傳遞所有日子。我只想傳遞選定的listview項目。請建議我在OnCheckBoxCommand方法中出了什麼問題。

Answer 1

這是我的發現;
在代碼中使用此代碼FormWeek.xaml的背後：

 

    private void SelectDays(object sender, SelectionChangedEventArgs e) 
    { 
    (this.DataContext as TaskExecDefinitionViewModel).OnCheckBoxCommand(checkedListView.SelectedItems,true); 
    } 
 

而在 'OnCheckBoxCommand'： -

public void OnCheckBoxCommand(object obj, bool _direction) 
    { 
     try 
     { 
      if (SelectedItems == null) SelectedItems = new ObservableCollection<string>(); 

      if (obj != null) 
      { 
       SelectedItems.Clear(); 
       var _list = ((IList)obj).Cast<string>().ToList(); 
       if (_direction) 
       { 
       _list.ForEach(item => SelectedItems.Add(item)); 
       } 
      } 
      else 
      SelectedItems.Clear();       
     } 
     catch (Exception ex) 
     { 
      MessageBox.Show(ex.Message, "TaskDefinition:OnCheckBoxCommand"); 
     } 
} 

有一個愉快的一天男人.....繼續下去。

Answer 2

嗨嘗試這樣的事情

<StackPanel Grid.Column="1" Grid.Row="3" Margin="5"> 
    <CheckBox x:Name="selectAll" Content="Select all" Command="{Binding CheckBoxCommand}" CommandParameter="{Binding IsChecked, RelativeSource={RelativeSource Mode=Self}}"/> 
    <ListView x:Name="checkedListView" SelectionMode="Extended" ItemsSource="{Binding CollectionOfDays}" SelectedItem="{Binding SelectedItems}"/> 
</StackPanel> 

public class MainViewModel 
{ 
    public MainViewModel() 
    { 
     CollectionOfDays = new ObservableCollection<string>(); 
     SelectedItems = new ObservableCollection<string>(); 

     CollectionOfDays.Add("Saturday"); 
     CollectionOfDays.Add("Sunday"); 
     CollectionOfDays.Add("Monday"); 
     CollectionOfDays.Add("Tuesday"); 
     CollectionOfDays.Add("Wednesday"); 
     CollectionOfDays.Add("Thursday"); 
     CollectionOfDays.Add("Friday"); 
    } 

    private CommandHandler _checkBoxCommand; 

    public CommandHandler CheckBoxCommand 
    { 
     get 
     { 
      return _checkBoxCommand ?? (_checkBoxCommand=new CommandHandler((param)=>OnCheckBoxCommand(param))); 
     } 
    } 

    public ObservableCollection<string> CollectionOfDays { get; set; } 

    public ObservableCollection<string> SelectedItems {get;set;} 

    private void OnCheckBoxCommand(object obj) 
    { 

     if (obj is bool) 
     { 
      if (SelectedItems == null) 
       SelectedItems = new ObservableCollection<string>(); 

      if ((bool)obj) 
      { 
       SelectedItems.Clear(); 
       foreach (var item in CollectionOfDays) 
       { 
        SelectedItems.Add(item); 
       } 
      } 
      else 
       SelectedItems.Clear(); 
     } 
    } 

} 

public MainWindow() 
    { 
     InitializeComponent(); 
     DataContext = new MainViewModel(); 
    } 

我希望這會給你一個想法。