AdaptiveGridView中的双向数据绑定

Question

I'm create a UWP app where I'm using the AdaptiveGridView control to display a list of items.

When I first set the ItemsSource of the AdaptiveGridView everything works as expected and I see the list rendered.

However if I try to add a new item to the ItemsSource property of the AdaptiveGridView, that new item does not show up. But when inspecting the ItemsSource, I can see that the new item was indeed added, but it does not show up.

The only way around this that i've tried was first to set the ItemsSource property to null, then set it again with the new item.

<Page.Resources>
    <DataTemplate x:Key="Items">
        <Grid Name="GoalCardGrid">
            <!--UI stuff-->
        </Grid>
    </DataTemplate>
</Page.Resources>
<StackPanel Margin="10,0,10,0">
    <UI:AdaptiveGridView Margin="0,20,0,0" HorizontalAlignment="Stretch" Grid.Row="2" x:Name="ItemsGV" 
                         ItemHeight="250" DesiredWidth="700" ItemTemplate="{StaticResource Items}">
    </UI:AdaptiveGridView>
</StackPanel>

    public static List<Item> Items = new List<Item>();

    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        base.OnNavigatedTo(e);

        Items.Add(new Item()
        {
            ImageUrl = "ms-appx:///Assets/download (1).jpeg"
        });

        Items.Add(new Item()
        {
            ImageUrl = "ms-appx:///Assets/download (2).jpeg"
        });

        ItemsGV.ItemsSource = Items;
    }

    private void AddGoalBtn_Click(object sender, RoutedEventArgs e)
    {
        Items.Add(new Item()
        {
            ImageUrl = "ms-appx:///Assets/download (1).jpeg"
        });
        ItemsGV.ItemsSource = null;
        ItemsGV.ItemsSource = Items;
    }

New items should be displayed when I add them, however they don't and I had to

Answer 1

The List class has not implemented the INotifyPropertyChanged Interface , when the new items are add in it, it will notify the UI.

To solve your issue, please use the ObservableCollection .

using System.Collections.ObjectModel;

public static ObservableCollection<Item> Items = new ObservableCollection<Item>();