CollectionView — .NET MAUI

• A data source (typically ObservableCollection<T>) bound to ItemsSource
• A DataTemplate defining how each item renders
• Optional: layout configuration, selection mode, grouping model, empty view

Basic Setup

<CollectionView ItemsSource="{Binding Items}">
    <CollectionView.ItemTemplate>
        <DataTemplate x:DataType="models:Item">
            <HorizontalStackLayout Padding="8" Spacing="8">
                <Image Source="{Binding Icon}" WidthRequest="40" HeightRequest="40" />
                <Label Text="{Binding Name}" VerticalOptions="Center" />
            </HorizontalStackLayout>
        </DataTemplate>
    </CollectionView.ItemTemplate>
</CollectionView>

Key rules:

• Bind ItemsSource to an ObservableCollection<T> so the UI updates on add/remove.
• Each item template root must be a Layout or View — never use ViewCell.
• Always set x:DataType on DataTemplate for compiled bindings.

Layouts

Set ItemsLayout to control arrangement. Default is VerticalList.

Grid Layout

<CollectionView ItemsSource="{Binding Items}">
    <CollectionView.ItemsLayout>
        <GridItemsLayout Orientation="Vertical"
                         Span="2"
                         VerticalItemSpacing="8"
                         HorizontalItemSpacing="8" />
    </CollectionView.ItemsLayout>
    <CollectionView.ItemTemplate>
        <DataTemplate x:DataType="models:Item">
            <Border Padding="8" StrokeThickness="0">
                <VerticalStackLayout>
                    <Image Source="{Binding Image}" HeightRequest="120" Aspect="AspectFill" />
                    <Label Text="{Binding Name}" FontAttributes="Bold" />
                </VerticalStackLayout>
            </Border>
        </DataTemplate>
    </CollectionView.ItemTemplate>
</CollectionView>

Horizontal List

<CollectionView ItemsSource="{Binding Items}"
                ItemsLayout="HorizontalList" />

Selection

Selection Mode

<CollectionView ItemsSource="{Binding Items}"
                SelectionMode="Single"
                SelectedItem="{Binding CurrentItem, Mode=TwoWay}"
                SelectionChangedCommand="{Binding ItemSelectedCommand}" />

For Multiple selection, bind SelectedItems (type IList<object>):

<CollectionView SelectionMode="Multiple"
                SelectedItems="{Binding ChosenItems, Mode=OneWay}" />

Selected Visual State

Highlight selected items using VisualStateManager:

<CollectionView.ItemTemplate>
    <DataTemplate x:DataType="models:Item">
        <Grid Padding="8">
            <VisualStateManager.VisualStateGroups>
                <VisualStateGroup Name="CommonStates">
                    <VisualState Name="Normal">
                        <VisualState.Setters>
                            <Setter Property="BackgroundColor" Value="Transparent" />
                        </VisualState.Setters>
                    </VisualState>
                    <VisualState Name="Selected">
                        <VisualState.Setters>
                            <Setter Property="BackgroundColor"
                                    Value="{AppThemeBinding Light={StaticResource Primary}, Dark={StaticResource PrimaryDark}}" />
                        </VisualState.Setters>
                    </VisualState>
                </VisualStateGroup>
            </VisualStateManager.VisualStateGroups>
            <Label Text="{Binding Name}" />
        </Grid>
    </DataTemplate>
</CollectionView.ItemTemplate>

Grouping

1. Create a group class inheriting from List<T>:

public class AnimalGroup : List<Animal>
{
    public string Name { get; }
    public AnimalGroup(string name, List<Animal> animals) : base(animals)
    {
        Name = name;
    }
}

2. Bind to ObservableCollection<AnimalGroup> and set IsGrouped="True":

<CollectionView ItemsSource="{Binding AnimalGroups}"
                IsGrouped="True">
    <CollectionView.GroupHeaderTemplate>
        <DataTemplate x:DataType="models:AnimalGroup">
            <Label Text="{Binding Name}"
                   FontAttributes="Bold"
                   BackgroundColor="{StaticResource Gray100}"
                   Padding="8" />
        </DataTemplate>
    </CollectionView.GroupHeaderTemplate>
    <CollectionView.ItemTemplate>
        <DataTemplate x:DataType="models:Animal">
            <Label Text="{Binding Name}" Padding="16,4" />
        </DataTemplate>
    </CollectionView.ItemTemplate>
</CollectionView>

Pull-to-Refresh

Wrap CollectionView in a RefreshView. Set IsRefreshing back to false when done:

<RefreshView IsRefreshing="{Binding IsRefreshing}"
             Command="{Binding RefreshCommand}">
    <CollectionView ItemsSource="{Binding Items}" />
</RefreshView>

Incremental Loading (Infinite Scroll)

<CollectionView ItemsSource="{Binding Items}"
                RemainingItemsThreshold="5"
                RemainingItemsThresholdReachedCommand="{Binding LoadMoreCommand}" />

⚠️ Do NOT use with non-virtualizing layouts. LinearItemsLayout and GridItemsLayout support virtualization. Using BindableLayout on a StackLayout as an alternative to CollectionView has no virtualization, which triggers infinite threshold-reached events.

SwipeView — Binding from Inside DataTemplate

Commands inside a DataTemplate can't directly reach your ViewModel. Use RelativeSource AncestorType:

<CollectionView.ItemTemplate>
    <DataTemplate x:DataType="models:Item">
        <SwipeView>
            <SwipeView.RightItems>
                <SwipeItems>
                    <SwipeItem Text="Delete"
                               BackgroundColor="Red"
                               Command="{Binding BindingContext.DeleteCommand, Source={RelativeSource AncestorType={x:Type ContentPage}}}"
                               CommandParameter="{Binding}" />
                </SwipeItems>
            </SwipeView.RightItems>
            <Grid Padding="8">
                <Label Text="{Binding Name}" />
            </Grid>
        </SwipeView>
    </DataTemplate>
</CollectionView.ItemTemplate>

EmptyView

Shown when ItemsSource is empty or null.

<CollectionView ItemsSource="{Binding SearchResults}"
                EmptyView="No items found." />

For a custom empty view, wrap in ContentView:

<CollectionView ItemsSource="{Binding SearchResults}">
    <CollectionView.EmptyView>
        <ContentView>
            <VerticalStackLayout HorizontalOptions="Center" VerticalOptions="Center">
                <Image Source="empty_state.png" WidthRequest="120" />
                <Label Text="Nothing here yet" HorizontalTextAlignment="Center" />
            </VerticalStackLayout>
        </ContentView>
    </CollectionView.EmptyView>
</CollectionView>

Headers and Footers

<CollectionView ItemsSource="{Binding Items}">
    <CollectionView.Header>
        <Label Text="Header" FontAttributes="Bold" Padding="8" />
    </CollectionView.Header>
    <CollectionView.Footer>
        <Label Text="Footer" FontAttributes="Italic" Padding="8" />
    </CollectionView.Footer>
</CollectionView>

Use HeaderTemplate / FooterTemplate when headers or footers are data-bound.

Scrolling

ScrollTo

Programmatically scroll by index or item:

// Scroll to index
collectionView.ScrollTo(index: 10, position: ScrollToPosition.Center, animate: true);

// Scroll to item
collectionView.ScrollTo(item: myItem, position: ScrollToPosition.MakeVisible, animate: true);

Snap Points

<CollectionView.ItemsLayout>
    <LinearItemsLayout Orientation="Horizontal"
                       SnapPointsType="MandatorySingle"
                       SnapPointsAlignment="Center" />
</CollectionView.ItemsLayout>

• SnapPointsType: None, Mandatory, MandatorySingle
• SnapPointsAlignment: Start, Center, End

Performance Tips

• Use MeasureFirstItem for uniform item sizes — significantly faster than MeasureAllItems:

  <LinearItemsLayout Orientation="Vertical" ItemSizingStrategy="MeasureFirstItem" />
  

• Always use ObservableCollection<T>, not List<T>. Swapping a List forces a full re-render.
• Update collections on the UI thread — MainThread.BeginInvokeOnMainThread(() => Items.Add(item)).

Common Pitfalls

References

• CollectionView overview
• CollectionView layout
• CollectionView selection
• CollectionView grouping
• CollectionView scrolling
• CollectionView EmptyView