MVVM Treeview選定項目

我希望有人願意幫助我。我對MVVM很新穎，閱讀完曼尼貼子後，我仍然無法弄清楚這一點。MVVM Treeview選定項目

我有EF數據庫填寫項目和計算屬於每個項目。我使用treeview和HierarchicalDataTemplate顯示項目和計算。當我點擊一個TreeView項目，我想一個標籤的文本綁定在

public string totaalPrijs

進行設置，但我只是無法弄清楚如何做到這一點！

這是我CalculationViewModel外觀

namespace Treeview_test1.ViewModel 
{ 
public class CalculationViewModel : ViewModelBase 
{ 
    public CalculationViewModel(TableItemChildren child) 
    { 
     this.Child = child; 
     IsChecked = false; 
    } 

    public TableItemChildren Child { get; protected set; } 

    public string totaalPrijs 
    { 
     get { return Child.dbTotaalPrijs; } 
     set 
     { 
      if (Child.dbTotaalPrijs != value) 
      { 
       Child.dbTotaalPrijs = value; 
       RaisePropertyChanged("totaalPrijs"); 
      } 
     } 
    } 

    private bool _isChecked; 
    public bool IsChecked 
    { 
     get { return _isChecked; } 
     set 
     { 
      if (_isChecked != value) 
      { 
       _isChecked = value; 
       RaisePropertyChanged("IsChecked"); 
      } 
     } 
    } 

}

，這裏是我的ItemViewModel

namespace Treeview_test1.ViewModel 
{ 
public class ItemViewModel : ViewModelBase 
{ 
    public ItemViewModel() 
    { 
     calcVMColl = new ObservableCollection<CalculationViewModel>(); 
     foreach (TableItemChildren calc in Service.getItemCalculations("1")) 
     { 
      calcVMColl.Add(new CalculationViewModel(calc)); 
     } 
    } 

    // Switch between real and mock data 
    private IGetCalculations _service; 
    public IGetCalculations Service 
    { 
     get 
     { 
      if (_service == null) 
      { 
       if (IsInDesignMode) 
        _service = new MockCalculations(); 
       else 
        _service = new GetCalculations(); 
      } 
      return _service; 
     } 
     set 
     { 
      _service = value; 
     } 
    } 

    private ObservableCollection<CalculationViewModel> _calcVMColl; 
    public ObservableCollection<CalculationViewModel> calcVMColl 
    { 
     get { return _calcVMColl; } 
     set 
     { 
      if (calcVMColl != value) 
      { 
       _calcVMColl = value; 
       RaisePropertyChanged("calcVMColl"); 
      } 
     } 
    } 
}

和XAML

<Window x:Class="Treeview_test1.MainWindow" xmlns="http://schemas.microsoft.com/ winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525" xmlns:ViewModel="clr-namespace:Treeview_test1.ViewModel"> 
<Window.DataContext> 
    <ViewModel:ItemViewModel /> 
</Window.DataContext> 
<Grid> 
    <Grid.ColumnDefinitions> 
     <ColumnDefinition Width="204" /> 
     <ColumnDefinition /> 
    </Grid.ColumnDefinitions> 
    <TreeView x:Name="tree" Width="195" HorizontalAlignment="Left" ItemsSource="{Binding calcVMColl}" Background="LightGray" Grid.Column="0" RenderTransformOrigin="1.016,0.509"> 
     <TreeView.ItemContainerStyle> 
      <Style TargetType="{x:Type TreeViewItem}"> 
       <Setter Property="IsSelected" Value="{Binding IsChecked, Mode=TwoWay}" /> 
       <Style.Triggers> 
        <Trigger Property="IsSelected" Value="True"> 
         <Setter Property="FontSize" Value="10" /> 
        </Trigger> 
       </Style.Triggers> 
      </Style> 
     </TreeView.ItemContainerStyle> 
     <TreeView.Resources> 
      <DataTemplate DataType="{x:Type ViewModel:CalculationViewModel}"> 
       <Label Content="{Binding totaalPrijs}" /> 
      </DataTemplate> 
     </TreeView.Resources> 
    </TreeView> 
    <Label Grid.Column="1" HorizontalAlignment="Left" Margin="39,39,0,0" VerticalAlignment="Top" Content="{Binding....?}" Foreground="Black" FontFamily="segeo ui" FontSize="20" /> 
</Grid>

因此，在短期：如何綁定文本我的標籤到當前選定的樹視圖項？

在此先感謝

阿迪

來源

2013-06-11 addy

綁定的TreeView的SelectedItem到Label（或TextBlock）是相當簡單：

<TreeView Name="myTreeview"/> 
<TextBlock Text="{Binding SelectedItem, ElementName=myTreeview, Mode=OneWay}"/>

但是事實上這並不會顯示你想要什麼，因爲TreeView的SelectedItem通常是Object而您需要string以顯示在TextBlock。

處理此問題的一種方法是在綁定上使用Converter。您可以實施IValueConverter並讓它從SelectedItem返回所需的字符串。

class GetTextFromItemConverter : IValueConverter 
    { 
     object IValueConverter.Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) 
     { 
     TreeViewItem itm = (TreeViewItem)value; 
     string myString = null; 
     //Retrieve whatever portion of the TreeViewItem you want to put in myString. 
     return myString; 
     } 

     object IValueConverter.ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) 
     { 
     throw new NotImplementedException(); 
     } 
    }

然後在你的TextBlock綁定將是這樣的：

<TextBlock Text="{Binding SelectedItem, Converter={StaticResource GetTextFromItemConverter}, ElementName=myTreeview, Mode=OneWay}"/>

來源

2013-06-12 18:55:04 Stewbob

MVVM Treeview選定項目

回答

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