VirtualizedGrid

A high-performance virtualized grid that supports optional grouping with sticky headers, orientation-aware column counts, and built-in load-more pagination. Only the items currently visible in the viewport are created and measured, keeping memory use flat regardless of data set size.

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Frameworks

.NET MAUI

Blazor

Features

• Virtualization — Native recycling on Android (RecyclerView + GridLayoutManager), compositional layout on iOS (UICollectionViewCompositionalLayout), and ItemsRepeater + UniformGridLayout on Windows. Blazor uses the built-in <Virtualize> component with CSS Grid.
• Sticky Group Headers — When IsGroupingEnabled is true, group headers pin to the top of the viewport as the user scrolls through a group.
• Orientation-Aware Columns — Set PortraitColumnCount and LandscapeColumnCount independently so the layout adapts automatically on device rotation.
• Load-More Pagination — A LoadMoreThreshold triggers LoadMoreRequested before the user reaches the last item; an optional ShowLoadMoreButton renders an explicit button for manual triggering.
• Item Visibility Events — ItemVisibleCommand and ItemHiddenCommand fire as items enter and leave the viewport (MAUI).
• Flexible Templates — Header, footer, empty view, group header, and load-more button are all fully templatable.

AI Skill

Claude Code GitHub Copilot

Step 1 — Add the marketplace:

claude plugin marketplace add shinyorg/skills

Step 2 — Install plugins:

claude plugin install shiny-client@shiny

BLE, GPS, Jobs, Notifications, Push, HTTP Transfers, OBD, Music, Health, DataSync — iOS, Android, Windows, MacOS, Linux, Web

claude plugin install shiny-maui@shiny

Shell, Contact Store

claude plugin install controls@shiny

TableView, BottomSheet, PillView, ImageViewer, Scheduler, Markdown, Mermaid Diagrams — MAUI and Blazor

claude plugin install shiny-mediator@shiny

Mediator/CQRS with middleware and source generators

claude plugin install shiny-data@shiny

DocumentDB and Spatial data libraries

claude plugin install shiny-aspire@shiny

Orleans and Gluetun Aspire integrations

claude plugin install shiny-extensions@shiny

DI, Stores, Reflector, Localization, Hosting modules

Step 1 — Add the marketplace:

copilot plugin marketplace add https://github.com/shinyorg/skills

Step 2 — Install plugins:

copilot plugin install shiny-client@shiny

BLE, GPS, Jobs, Notifications, Push, HTTP Transfers, OBD, Music, Health, DataSync — iOS, Android, Windows, MacOS, Linux, Web

copilot plugin install shiny-maui@shiny

Shell, Contact Store

copilot plugin install controls@shiny

TableView, BottomSheet, PillView, ImageViewer, Scheduler, Markdown, Mermaid Diagrams — MAUI and Blazor

copilot plugin install shiny-mediator@shiny

Mediator/CQRS with middleware and source generators

copilot plugin install shiny-data@shiny

DocumentDB and Spatial data libraries

copilot plugin install shiny-aspire@shiny

Orleans and Gluetun Aspire integrations

copilot plugin install shiny-extensions@shiny

DI, Stores, Reflector, Localization, Hosting modules

View Skills Repository

Quick Start

.NET MAUI

<shiny:VirtualizedGrid ItemsSource="{Binding Products}"
                       PortraitColumnCount="2"
                       LandscapeColumnCount="4"
                       IsGroupingEnabled="True"
                       HasStickyHeaders="True"
                       CellPadding="8"
                       ShowLoadMoreButton="False"
                       IsLoadingMore="{Binding IsLoadingMore}"
                       ItemSelectedCommand="{Binding SelectProductCommand}">
    <shiny:VirtualizedGrid.ItemTemplate>
        <DataTemplate>
            <Border StrokeShape="{RoundRectangle CornerRadius=8}" Padding="8">
                <Label Text="{Binding Name}" />
            </Border>
        </DataTemplate>
    </shiny:VirtualizedGrid.ItemTemplate>
    <shiny:VirtualizedGrid.GroupHeaderTemplate>
        <DataTemplate>
            <Label Text="{Binding Key}" FontAttributes="Bold" FontSize="16" />
        </DataTemplate>
    </shiny:VirtualizedGrid.GroupHeaderTemplate>
</shiny:VirtualizedGrid>

Blazor

<VirtualizedGrid Items="products"
                 ColumnCount="2"
                 ItemSpacing="8"
                 IsGroupingEnabled="true"
                 HasStickyHeaders="true"
                 EnableVirtualization="true"
                 LoadMoreThreshold="5"
                 IsLoadingMore="isLoadingMore"
                 LoadMoreRequested="OnLoadMore"
                 ItemSelected="OnProductSelected">
    <ItemTemplate Context="product">
        <div class="product-card">
            <span>@product.Name</span>
        </div>
    </ItemTemplate>
    <GroupHeaderTemplate Context="group">
        <h3>@group</h3>
    </GroupHeaderTemplate>
    <EmptyViewTemplate>
        <p>No products found.</p>
    </EmptyViewTemplate>
</VirtualizedGrid>

@code {
    List<Product> products = [];
    bool isLoadingMore = false;

    async Task OnLoadMore()
    {
        isLoadingMore = true;
        // fetch next page...
        isLoadingMore = false;
    }

    void OnProductSelected(Product product) { }
}

Properties

MAUI

Property	Type	Default	Description
ItemsSource	IEnumerable	—	Collection of items or grouped collections
ItemTemplate	DataTemplate	—	Template for each grid cell
ColumnCount	int	1	Default column count
PortraitColumnCount	int?	null	Column count in portrait orientation; overrides ColumnCount
LandscapeColumnCount	int?	null	Column count in landscape orientation; overrides ColumnCount
CellPadding	Thickness	—	Padding applied inside each cell
IsGroupingEnabled	bool	false	Enable grouped data with group headers
GroupHeaderTemplate	DataTemplate	—	Template for group header rows
HasStickyHeaders	bool	true	Pin group headers to the top while scrolling
ShowLoadMoreButton	bool	false	Render an explicit load-more button as a footer at the end of the data
LoadMoreButtonTemplate	DataTemplate	—	Custom template for the load-more button; defaults to a centered “Load More” button
IsLoadingMore	bool	false	Indicates a load-more operation is in progress
ItemSelectedCommand	ICommand	—	Command fired when a cell is tapped
ItemVisibleCommand	ICommand	—	Command fired when a cell enters the viewport
ItemHiddenCommand	ICommand	—	Command fired when a cell leaves the viewport

Blazor

Property	Type	Default	Description
Items	IReadOnlyList<TItem>	—	Flat list of items
ItemTemplate	RenderFragment<TItem>	—	Template for each grid cell
HeaderTemplate	RenderFragment	—	Content rendered above the grid
FooterTemplate	RenderFragment	—	Content rendered below the grid
EmptyViewTemplate	RenderFragment	—	Content rendered when Items is empty
ColumnCount	int	1	Number of grid columns
ItemSpacing	double	8	Gap between cells in px
CellPaddingLeft	double	—	Left padding inside each cell
CellPaddingRight	double	—	Right padding inside each cell
CellPaddingTop	double	—	Top padding inside each cell
CellPaddingBottom	double	—	Bottom padding inside each cell
IsGroupingEnabled	bool	false	Enable grouped rendering
GroupedItems	IReadOnlyList<VirtualizedGridGroup<TItem>>	—	Pre-grouped data source used when IsGroupingEnabled is true
GroupHeaderTemplate	RenderFragment<object>	—	Template for group header rows
HasStickyHeaders	bool	true	Pin group headers while scrolling
EnableVirtualization	bool	false	Use Blazor <Virtualize> for large datasets
LoadMoreThreshold	int	5	Number of items from the end that triggers LoadMoreRequested
ShowLoadMoreButton	bool	false	Render an explicit load-more button
IsLoadingMore	bool	false	Indicates a load-more operation is in progress
LoadMoreRequested	EventCallback	—	Fired when the threshold is reached or the load-more button is clicked
ItemSelected	EventCallback<TItem>	—	Fired when a cell is clicked/tapped

Events & Commands

MAUI:

• ItemSelectedCommand (ICommand) — Fires on cell tap; parameter is the selected item
• ItemVisibleCommand (ICommand) — Fires as a cell scrolls into the visible area
• ItemHiddenCommand (ICommand) — Fires as a cell scrolls out of the visible area

Blazor:

• LoadMoreRequested (EventCallback) — Fires when proximity threshold is reached or load-more button is pressed
• ItemSelected (EventCallback<TItem>) — Fires on cell click/tap

Behavior

• When both PortraitColumnCount and LandscapeColumnCount are set, ColumnCount is ignored and the appropriate value is chosen based on current device orientation
• Sticky headers require IsGroupingEnabled="true"; setting HasStickyHeaders="false" renders standard (non-sticky) group headers
• LoadMoreThreshold counts from the last item; reaching that position fires LoadMoreRequested automatically even without ShowLoadMoreButton
• Setting IsLoadingMore="true" shows a built-in activity indicator in the load-more area until the value returns to false
• EnableVirtualization in Blazor requires Items to be provided as a flat list; use GroupedItems alongside IsGroupingEnabled for grouped virtualized rendering