Question

我有一个绑定到ParentViewModel的Observablecollection的树视图。

ParentViewModel包含一个Observablecollection of ChildViewModel。

此ViewModel都实现了IsSelected属性。我把它放在它们两个中因为实现有点不同。如果我按下父项或子项，程序必须有不同的行为。

我的问题是，如果我选择子项，程序也会执行ParentViewModel的IsSelected属性，而不是ChildViewModel的属性。

这是我的XAML：

         <TreeView Name="MyTreeView"
        ItemsSource="{Binding ParentList}">

        <TreeView.ItemContainerStyle>
           <Style TargetType="{x:Type TreeViewItem}">
              <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
           </Style>
        </TreeView.ItemContainerStyle>

        <TreeView.Resources>
           <HierarchicalDataTemplate DataType="{x:Type local:ParentViewModel}" ItemsSource="{Binding Childs}">

              <Grid >
                 <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="Auto"/>
                    <ColumnDefinition Width="1*"/>
                 </Grid.ColumnDefinitions>

                 <Image Grid.Column="0" Source="{Binding PictureString}" Height="32" Width="32" Margin="0,8,6,4" />
                 <TextBlock Grid.Column="1" Text="{Binding Name}" FontSize="15" Margin="10" />

              </Grid>

              <HierarchicalDataTemplate.ItemContainerStyle>
                 <Style TargetType="{x:Type TreeViewItem}">
                    <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
                 </Style>
              </HierarchicalDataTemplate.ItemContainerStyle>

           </HierarchicalDataTemplate>

           <DataTemplate DataType="{x:Type local:ChildViewModel}">
              <Grid >
                 <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="Auto"/>
                    <ColumnDefinition Width="1*"/>
                 </Grid.ColumnDefinitions>

                 <!--<Image Grid.Column="0" Source="{Binding PictureString}" Height="32" Margin="0,8,6,4" />-->
                 <TextBlock Grid.Column="1" Text="{Binding Name}" Height="18" FontSize="15"  Margin="10"/>

              </Grid>
           </DataTemplate>

        </TreeView.Resources>

     </TreeView>

该程序从未命中ChildViewModel的IsSelected setter。

提前致谢

修改

这是BaseViewModel：

Public Class InheritableTreeViewItem
   Implements INotifyPropertyChanged

   Friend m_Name As String
   Public Property Name As String
      Get
         Return m_Name
      End Get
      Set(value As String)
         If (value <> m_Name) Then
            m_Name = value
            NotifyPropertyChanged("Name")
         End If
      End Set
   End Property

   Friend m_IsSelected As Boolean
   Public Overridable Property IsSelected As Boolean
      Get
         Return m_IsSelected
      End Get
      Set(value As Boolean)
         If (value <> m_IsSelected) Then
            m_IsSelected = value
            NotifyPropertyChanged("IsSelected")
         End If
      End Set
   End Property


   Private m_sPictureString As String
   Private m_Items As ObservableCollection(Of InheritableTreeViewItem)

   Public Property PictureString As String
      Get
         Return m_sPictureString
      End Get
      Set(value As String)
         If value <> m_sPictureString Then
            m_sPictureString = value
            NotifyPropertyChanged("PictureString")
         End If
      End Set
   End Property

   Public Property Items As ObservableCollection(Of InheritableTreeViewItem)
      Get
         Return m_Items
      End Get
      Set(value As ObservableCollection(Of InheritableTreeViewItem))
         m_Items = value
      End Set
   End Property

   Sub New(Name As String)
      Me.Name = Name
      Me.Items = New ObservableCollection(Of InheritableTreeViewItem)
   End Sub

   Public Event PropertyChanged As PropertyChangedEventHandler Implements    INotifyPropertyChanged.PropertyChanged

   Public Sub NotifyPropertyChanged(propName As String)
      RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propName))
   End Sub


End Class

这是ParentViewModel：

Public Class ParentViewModel
   Inherits InheritableTreeViewItem

   Public Overrides Property IsSelected As Boolean
      Get
         Return m_IsSelected
      End Get
      Set(value As Boolean)
         If (value <> m_IsSelected) Then
            m_IsSelected = value
            If value Then
               ' The function that I want to call When Parent item is selected in the tree
            End If
            NotifyPropertyChanged("IsSelected")
         End If
      End Set
   End Property

   Sub New(Name As String)
      MyBase.New(Name)
      Me.PictureString = "/Resources/TreeView/Folder.png"
   End Sub

End Class

ChildViewModel基本相同，它仅在我选择时调用的函数不同。此函数修改某些TextBox的内容和可见性。

Answer 1

我认为你的问题出在这个街区：

<TreeView.ItemContainerStyle>
    <Style TargetType="{x:Type TreeViewItem}">
        <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
    </Style>
</TreeView.ItemContainerStyle>

因为它是一种样式，我不确定DataContext是否被正确继承。另外，为什么要在HierarchicalDataTemplate中重新定义它？我认为您不需要为ChildViewModelItems重新定义此样式。

也许你可以深入调试你的数据绑定，看看这个属性上发生了什么：How to debug data binding。

此外，儿童的复数是儿童，而不是儿童;）

使用不同的viewmodel选择Treeview

1 个答案: