數據網格元素在分組後不顯示

Question

我有一個DataGrid綁定到ListCollectionView包含幾個項目與ListCollectionView的分組功能分組。如果我沒有添加GroupDescription（因此沒有應分組的項目），項目會正確顯示。但是，當我設置GroupDescription時，可以看到每個組的項目名稱和計數，但項目本身未顯示。

請問有人能指出我在做什麼錯嗎？

ItemsView.xaml

<DataGrid Grid.Column="0" 
       BorderThickness="0" 
       ItemsSource="{Binding ItemsTable}" 
       AutoGenerateColumns="False" 
       IsReadOnly="True" 
       CanUserAddRows="False"> 
     <DataGrid.Columns> 
      <DataGridTextColumn Header="Name" Binding="{Binding Name}"/> 
      <DataGridTextColumn Header="Weight" Binding="{Binding Weight}"/> 
      <DataGridTextColumn Header="Price" Binding="{Binding Price}"/> 
      <DataGridTextColumn Header="Category" Binding="{Binding Category}"/> 
     </DataGrid.Columns> 
     <DataGrid.RowDetailsTemplate> 
      <DataTemplate> 
       <StackPanel Margin="5"> 
        <TextBlock Text="{Binding Series.Name}" FontWeight="Black" FontSize="14" Margin="0,0,0,2" /> 
        <TextBlock><Run FontWeight="Bold" Text="{Binding Series.Spec1.Name}" /> - <Run Text="{Binding SpecOption1.Name}" /> $<Run Text="{Binding SpecOption1.Price}" /></TextBlock> 
        <TextBlock><Run FontWeight="Bold" Text="{Binding Series.Spec2.Name}" />: <Run Text="{Binding SpecOption2.Name}" /> $<Run Text="{Binding SpecOption2.Price}" /></TextBlock> 
        <TextBlock><Run FontWeight="Bold" Text="{Binding Series.Spec3.Name}" />: <Run Text="{Binding SpecOption3.Name}" /> $<Run Text="{Binding SpecOption3.Price}" /></TextBlock> 
        <TextBlock><Run FontWeight="Bold" Text="{Binding Series.Spec4.Name}" />: <Run Text="{Binding SpecOption4.Name}" /> $<Run Text="{Binding SpecOption4.Price}" /></TextBlock> 
        <TextBlock><Run FontWeight="Bold" Text="{Binding Series.Spec5.Name}" />: <Run Text="{Binding SpecOption5.Name}" /> $<Run Text="{Binding SpecOption5.Price}" /></TextBlock> 
        <TextBlock><Run FontWeight="Bold" Text="{Binding Series.Spec6.Name}" />: <Run Text="{Binding SpecOption6.Name}" /> $<Run Text="{Binding SpecOption6.Price}" /></TextBlock> 
        <TextBlock><Run FontWeight="Bold" Text="{Binding Series.Spec7.Name}" />: <Run Text="{Binding SpecOption7.Name}" /> $<Run Text="{Binding SpecOption7.Price}" /></TextBlock> 
       </StackPanel> 
      </DataTemplate> 
     </DataGrid.RowDetailsTemplate> 
     <DataGrid.GroupStyle> 
      <GroupStyle> 
       <GroupStyle.HeaderTemplate> 
        <DataTemplate> 
         <StackPanel> 
          <TextBlock Text="{Binding Path=Name}" /> 
         </StackPanel> 
        </DataTemplate> 
       </GroupStyle.HeaderTemplate> 
       <GroupStyle.ContainerStyle> 
        <Style TargetType="{x:Type GroupItem}"> 
         <Setter Property="Template"> 
          <Setter.Value> 
           <ControlTemplate TargetType="{x:Type GroupItem}"> 
            <Expander> 
             <Expander.Header> 
              <StackPanel Orientation="Horizontal"> 
               <TextBlock Text="{Binding Path=Name}" /> 
               <TextBlock Text="-" Margin="3,0,3,0" /> 
               <TextBlock Text="{Binding Path=ItemCount}" Margin="0,0,3,0" /> 
               <TextBlock Text="Item(s)" /> 
              </StackPanel> 
             </Expander.Header> 
            </Expander> 
           </ControlTemplate> 
          </Setter.Value> 
         </Setter> 
        </Style> 
       </GroupStyle.ContainerStyle> 
      </GroupStyle> 
     </DataGrid.GroupStyle> 
    </DataGrid> 

ItemsViewModel.cs

/// <summary> 
/// This class contains properties that a View can data bind to. 
/// <para> 
/// See http://www.galasoft.ch/mvvm 
/// </para> 
/// </summary> 
public class FarrisItemsViewModel : ViewModelBase 
{ 
    /// <summary> 
    /// Initializes a new instance of the FarrisItemsViewModel class. 
    /// </summary> 
    public FarrisItemsViewModel() 
    { 
     // 

     ObservableCollection<Item> itemCollection = new ObservableCollection<Item>(); 

     itemCollection.Add(new Item("Part01", 2033, 10)); 
     itemCollection.Add(new Item("Part02", 4420, 10)); 
     itemCollection.Add(new Item("Part03", 12614, 10)); 

     ListCollectionView itemCollectionView = new ListCollectionView(itemCollection); 

     //itemCollectionView.GroupDescriptions.Add(new PropertyGroupDescription("Category")); 

     ItemsTable = itemCollectionView; 

    } 

    /// <summary> 
    /// The <see cref="ItemsTable" /> property's name. 
    /// </summary> 
    public const string ItemsTablePropertyName = "ItemsTable"; 

    private ListCollectionView _itemsTable = null; 

    /// <summary> 
    /// Sets and gets the ItemsTable property. 
    /// Changes to that property's value raise the PropertyChanged event. 
    /// </summary> 
    public ListCollectionView ItemsTable 
    { 
     get 
     { 
      return _itemsTable; 
     } 

     set 
     { 
      if (_itemsTable == value) 
      { 
       return; 
      } 

      RaisePropertyChanging(ItemsTablePropertyName); 
      _itemsTable = value; 
      RaisePropertyChanged(ItemsTablePropertyName); 
     } 
    } 
} 

Answer 1

那是因爲你沒有設置Expander.Content顯示ItemsPresenter。你的Expander看起來應該是這樣的：

<Expander> 
    <Expander.Header> 
    <DockPanel> 
     <TextBlock Text="{Binding Path=Name}" /> 
     <TextBlock Text="{Binding Path=ItemCount}"/> 
    </DockPanel> 
    </Expander.Header> 
    <Expander.Content> 
    <ItemsPresenter /> 
    </Expander.Content> 
</Expander>