WPF ItemsControl绑定在绑定到视图模型中的对象中的ObservableCollection时不会更新

Question

Basically I have an object in my view model that contains an ObservableCollection of a custom object. My XAML's DataContext is set to my ViewModel, my ViewModel contains a 'Scratchdisk' object, and the Scratchdisk object contains an ObservableCollection of Frame objects. Both the Scratchdisk and the Collection are set up as DependencyProperties.

In short: XAML --DataContext--> EditorViewModel --DependencyProperty--> Scratchdisk --DependencyProperty--> ObservableCollection<Frame>

The Frame object has 3 standard properties: Index, Image, and ImageUrl.

I'm trying to bind to the ObservableCollection in my XAML using this code:

<ItemsControl DataContext="{Binding Source=ThumbnailScratchdisk}" ItemsSource="{Binding Frames, UpdateSourceTrigger=PropertyChanged}" ItemTemplate="{StaticResource ThumbnailTemplate}">
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <VirtualizingStackPanel Orientation="Horizontal"></VirtualizingStackPanel>
         </ItemsPanelTemplate>
     </ItemsControl.ItemsPanel>
</ItemsControl>

Where ThumbnailTemplate is defined in Window Resources as:

<DataTemplate x:Key="ThumbnailTemplate">
    <Image Width="128" Height="96" Source="{Binding ImageUrl}"/>
</DataTemplate>

Theoretically, what should happen is, the Scratchdisk should receive filenames, create Frame objects, add them to the Collection, and then the binding should display them. The ObservableCollection is working and being populated, but the binding doesn't seen to be updating. All the updatable properties are set as DependencyProperties so the binding should update shouldn't it?

Links to the files:

XAML

ViewModel

Scratchdisk

Frame

Answer 1

The problem is in the binding of the DataContext of your ItemsControl . You're setting it to "{Binding Source=ThumbnailScratchdisk}" , but what you (presumably) want is to set it to just "{Binding ThumbnailScratchdisk}" .

The DataContext of the page is already an instance of EditorViewModel , and you want the DataContext for the ItemsControl to bind to the property ThumbnailScratchdisk of that viewmodel.

Answer 2

尝试将XAML中的绑定路径更改为ThumbnailScratchdisk.Frames