Question

我有一个名为＆＃34; A＆＃34;的ViewModel，包含ObservableCollection类型的属性（Of ChannelViewModel）。 Model实际上在这个ChannelViewModel类中，我对此很好。

在View＆＃34; A＆＃34;中，我有一个StackSnel，ItemsSource填充了ObservableCollection。我添加了一个DataTemplate来显示一个自定义控件＆＃34; Channel＆＃34;而不是ChannelViewModel字符串。 Channel自定义控件需要显示ChannelViewModel数据。

问题是Channel的DataContext没有正确连接到列表的每个项目。我试了很多东西似乎没什么用。我很感激你的帮助！

这是＆＃34; A＆＃34;查看代码：

<Window.DataContext>
    <ctrls:AViewModel/>
</Window.DataContext>
<StackPanel x:Name="uiStack" Orientation="Horizontal">
    <ItemsControl ItemsSource="{Binding Channels}">
        <ItemsControl.ItemTemplate>
            <DataTemplate>
                 <ctrls:Channel DataContext="{Binding DataContext}"  />
            </DataTemplate>
        </ItemsControl.ItemTemplate>
        <ItemsControl.ItemsPanel>
            <ItemsPanelTemplate>
                 <WrapPanel/>
            </ItemsPanelTemplate>
        </ItemsControl.ItemsPanel>                
    </ItemsControl>            
</StackPanel>

这是＆＃34; A＆＃34; ViewModel：

Private aChannels As New ObservableCollection(Of ChannelViewModel)
Property Channels As ObservableCollection(Of ChannelViewModel)
    Get
        Return aChannels
    End Get
    Set(value As ObservableCollection(Of ChannelViewModel))
        aChannels = value
        OnPropertyChanged("Channels")
    End Set
End Property

Public Sub New()
    AddChannels()
    OnPropertyChanged("Channels")
End Sub

Private Sub AddChannels()
    For i As Integer = 1 To DeviceConfig.Channels.Count
        Channels.Add(New ChannelViewModel(i)) 
    Next        
End Sub

Channel UserControl是（简化）：

<UserControl.DataContext>
    <ctrls:ChannelViewModel />
</UserControl.DataContext>
<StackPanel Orientation="Horizontal">
    <Label x:Name="lblChannelNo" Content="{Binding ChannelNo}" />
    <Label x:Name="lblChannelName" Content="{Binding ChannelName}" />
</StackPanel>

Channel ViewModel（简化）：

Public Class ChannelViewModel
    Inherits ViewModelBase

    Private aChannelNo As Integer = 0
    Property ChannelNo As Integer
        Get
            Return aChannelNo
        End Get
        Set(value As Integer)
            aChannelNo = value
            OnPropertyChanged("ChannelNo")
        End Set
    End Property

    Private aChannelName As String = "N/A"
    Property ChannelName As String
        Get
            Return aChannelName
        End Get
        Set(value As String)
            aChannelName = value
            OnPropertyChanged("ChannelName")
        End Set
    End Property

Answer 1

好的，问题发生在频道视图中。我认为设置DataContext会覆盖＆＃34; A＆＃34;视图。因此删除这些行解决了这个问题：

<UserControl.DataContext>
    <ctrls:ChannelViewModel />
</UserControl.DataContext>

我还必须将绑定更改为：

<DataTemplate>
    <ctrls:Channel DataContext="{Binding}"  />
</DataTemplate>

WPF从DataTemplate项绑定到父ItemsSource DataContext

1 个答案: