- 1 year ago
How to use Incremental Loading Collection with CollectionViewSource to group list view items in UWP?
In UWP (Universal Windows Platform), you can use the CollectionViewSource
with incremental loading to group items in a ListView
. Here's an example of how you can achieve this:
Define your data model: Create a data model class to represent your items. For grouping, you typically need a property that defines the group key.
csharppublic class ItemModel
{
public string Name { get; set; }
public string Group { get; set; }
}
Implement the incremental loading collection: Create a class that implements the
ISupportIncrementalLoading
interface to provide the incremental loading behavior. This class should handle loading items on-demand as the user scrolls through the list.csharppublic class IncrementalLoadingCollection : ObservableCollection<ItemModel>, ISupportIncrementalLoading
{
public bool HasMoreItems { get; private set; }
public IAsyncOperation<LoadMoreItemsResult> LoadMoreItemsAsync(uint count)
{
// Implement your logic to load more items asynchronously
// Add the loaded items to the collection
// Set HasMoreItems based on whether there are more items to load
HasMoreItems = /* Determine if there are more items to load */;
// Return the result indicating the number of items loaded
return Task.FromResult(new LoadMoreItemsResult { Count = count }).AsAsyncOperation();
}
}
Implement the
LoadMoreItemsAsync
method to load additional items into the collection. Set theHasMoreItems
property totrue
orfalse
based on whether there are more items to load.Set up the grouping and data binding in XAML: In your XAML file, define the
CollectionViewSource
with grouping settings and bind it to theListView
.xaml<Page
...
xmlns:local="using:YourNamespace"
xmlns:CollectionViewSource="using:Microsoft.Toolkit.Uwp.UI.Controls"
>
<Grid>
<Grid.Resources>
<CollectionViewSource:CollectionViewSource x:Key="GroupedItemsSource"
IsSourceGrouped="True"
ItemsPath="Items"
Source="{x:Bind YourIncrementalLoadingCollection}" />
</Grid.Resources>
<ListView ItemsSource="{Binding Source={StaticResource GroupedItemsSource}}">
<ListView.GroupStyle>
<GroupStyle>
<GroupStyle.HeaderTemplate>
<DataTemplate>
<TextBlock Text="{Binding Key}" />
</DataTemplate>
</GroupStyle.HeaderTemplate>
</GroupStyle>
</ListView.GroupStyle>
<ListView.ItemTemplate>
<DataTemplate x:DataType="local:ItemModel">
<TextBlock Text="{x:Bind Name}" />
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
</Page>
In this example, the
CollectionViewSource
is configured withIsSourceGrouped="True"
, indicating that grouping is enabled. TheItemsPath
property specifies the property in the data model (Items
) that contains the group's items. TheSource
property is bound to yourYourIncrementalLoadingCollection
instance.The
ListView
is bound to theCollectionViewSource
usingItemsSource="{Binding Source={StaticResource GroupedItemsSource}}"
. TheGroupStyle
specifies the template for the group headers, and theItemTemplate
defines the template for individual items.Set up the data binding in code-behind: In your code-behind file, create an instance of the
IncrementalLoadingCollection
and set it as theDataContext
for