avalonia-controls-data-display

name	avalonia-controls-data-display
description	Use when working with Avalonia data display controls: TextBlock, Label, ListBox, DataGrid, TreeView, ItemsControl, Carousel, or MarkdownViewer. Covers binding patterns, templates, virtualization, selection modes, and column configuration for Avalonia 12.

Avalonia Data Display Controls

Overview

Data display controls render read-only or selectable information. Prefer ItemsControl for simple lists, ListBox when selection is needed, DataGrid for tabular data, and TreeView for hierarchical data.

---

TextBlock

Property	Type	Notes
Text	string	Plain text content
FontSize	double	In device-independent pixels
FontWeight	FontWeight	Normal, Bold, SemiBold, etc.
FontStyle	FontStyle	Normal, Italic, Oblique
TextWrapping	TextWrapping	NoWrap, Wrap, WrapWithOverflow
TextTrimming	TextTrimming	None, CharacterEllipsis, WordEllipsis
TextDecorations	TextDecorationCollection	Underline, Strikethrough
LineHeight	double	Line spacing
MaxLines	int	Clamps number of displayed lines
Inlines	InlineCollection	Mixed-format inline content

<!-- Basic -->
<TextBlock Text="{Binding Title}" FontSize="18" FontWeight="SemiBold"/>

<!-- Trimming with ellipsis -->
<TextBlock Text="{Binding Description}" TextTrimming="CharacterEllipsis" MaxWidth="300"/>

<!-- Inline formatting -->
<TextBlock>
    <Run FontWeight="Bold">Important:</Run>
    <Run> This is </Run>
    <Run Foreground="Red" FontStyle="Italic">critical</Run>
    <LineBreak/>
    <Run Text="{Binding Detail}"/>
</TextBlock>

<!-- Underline + strikethrough -->
<TextBlock Text="Strike me" TextDecorations="Strikethrough"/>
<TextBlock Text="Link-style" TextDecorations="Underline" Cursor="Hand"/>

---

Label

Property	Type	Notes
Content	object	Text or XAML content
Target	IInputElement	Associates access key with target control

Use _ prefix in content to define an access key (Alt+key focuses Target).

<Label Content="_Username" Target="{Binding #usernameBox}"/>
<TextBox x:Name="usernameBox" Text="{Binding Username}"/>

<Label Content="_Password" Target="{Binding #passwordBox}"/>
<TextBox x:Name="passwordBox" PasswordChar="•" Text="{Binding Password}"/>

Note: Label adds padding and is a ContentControl. For pure display, prefer TextBlock.

---

ItemsControl

Base class for all list controls. Use directly when no selection is needed.

Property	Type	Notes
ItemsSource	IEnumerable	Bound collection
ItemTemplate	DataTemplate	Template for each item
ItemsPanel	ItemsPanelTemplate	Layout panel (default: StackPanel)
ItemContainerTheme	ControlTheme	Style for each container

<!-- Simple read-only list -->
<ItemsControl ItemsSource="{Binding Tags}">
    <ItemsControl.ItemTemplate>
        <DataTemplate x:DataType="vm:TagVm">
            <Border Background="#E3F2FD" CornerRadius="4" Padding="8,4" Margin="0,0,4,4">
                <TextBlock Text="{Binding Name}" FontSize="12"/>
            </Border>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
    <!-- Horizontal wrapping layout -->
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <WrapPanel Orientation="Horizontal"/>
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
</ItemsControl>

---

ListBox

Extends ItemsControl with selection. Virtualizes items by default.

Property	Type	Notes
SelectedItem	object	TwoWay by default
SelectedItems	IList	Multiple selection (requires SelectionMode flag)
SelectedIndex	int	Zero-based index
SelectionMode	SelectionMode	Single, Multiple, Toggle, AlwaysSelected
Scroll	ScrollViewer	Access the internal scroll viewer

<ListBox ItemsSource="{Binding People}"
         SelectedItem="{Binding SelectedPerson}"
         SelectionMode="Single">
    <ListBox.ItemTemplate>
        <DataTemplate x:DataType="vm:PersonVm">
            <StackPanel Margin="4">
                <TextBlock Text="{Binding FullName}" FontWeight="SemiBold"/>
                <TextBlock Text="{Binding Email}" FontSize="12" Foreground="Gray"/>
            </StackPanel>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

<!-- Multi-select -->
<ListBox ItemsSource="{Binding Files}"
         SelectionMode="Multiple,Toggle"
         SelectedItems="{Binding SelectedFiles}">
    <ListBox.ItemTemplate>
        <DataTemplate x:DataType="vm:FileVm">
            <TextBlock Text="{Binding Name}"/>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

---

DataGrid

Requires separate NuGet package: Avalonia.Controls.DataGrid

Add to App.axaml styles:

<StyleInclude Source="avares://Avalonia.Controls.DataGrid/Themes/Fluent.xaml"/>

Namespace: xmlns:dg="using:Avalonia.Controls"

Property	Type	Notes
ItemsSource	IEnumerable	Bound collection
AutoGenerateColumns	bool	False for manual columns
CanUserSortColumns	bool	Click-to-sort
CanUserResizeColumns	bool	Drag column edges
CanUserReorderColumns	bool	Drag column headers
GridLinesVisibility	DataGridGridLinesVisibility	All, Horizontal, Vertical, None
FrozenColumnCount	int	Columns that don't scroll
RowBackground	IBrush	Row fill
AlternatingRowBackground	IBrush	Alternating fill
SelectedItem	object	TwoWay
SelectionMode	DataGridSelectionMode	Single, Extended

Column types:

Type	Use for
DataGridTextColumn	String/primitive display
DataGridCheckBoxColumn	Boolean values
DataGridTemplateColumn	Custom cell content

<DataGrid ItemsSource="{Binding Employees}"
          AutoGenerateColumns="False"
          CanUserSortColumns="True"
          CanUserResizeColumns="True"
          GridLinesVisibility="Horizontal"
          AlternatingRowBackground="#F5F5F5"
          SelectedItem="{Binding SelectedEmployee}">
    <DataGrid.Columns>
        <DataGridTextColumn Header="Name" Binding="{Binding Name}" Width="*"/>
        <DataGridTextColumn Header="Department" Binding="{Binding Department}" Width="Auto"/>
        <DataGridTextColumn Header="Salary" Binding="{Binding Salary, StringFormat=C2}" Width="100"/>
        <DataGridCheckBoxColumn Header="Active" Binding="{Binding IsActive}" Width="60"/>
        <DataGridTemplateColumn Header="Actions" Width="80">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Button Content="Edit"
                            Command="{Binding $parent[DataGrid].DataContext.EditCommand}"
                            CommandParameter="{Binding}"
                            Padding="8,4"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>

Note: DataGrid column Binding always uses reflection bindings ({Binding ...}), even when the page uses compiled bindings. x:DataType on DataTemplate inside columns is not supported.

---

TreeView

Property	Type	Notes
ItemsSource	IEnumerable	Root nodes
ItemTemplate	TreeDataTemplate	Must use TreeDataTemplate for hierarchy
SelectedItem	object	TwoWay
AutoScrollToSelectedItem	bool	Scrolls to selection

TreeDataTemplate has an ItemsSource property that points to each node's children collection.

<TreeView ItemsSource="{Binding RootNodes}"
          SelectedItem="{Binding SelectedNode}"
          AutoScrollToSelectedItem="True">
    <TreeView.ItemTemplate>
        <TreeDataTemplate x:DataType="vm:TreeNodeVm" ItemsSource="{Binding Children}">
            <StackPanel Orientation="Horizontal" Spacing="6">
                <PathIcon Data="{Binding IconData}" Width="14" Height="14"/>
                <TextBlock Text="{Binding Name}"/>
            </StackPanel>
        </TreeDataTemplate>
    </TreeView.ItemTemplate>
</TreeView>

public class TreeNodeVm
{
    public string Name { get; set; } = "";
    public string IconData { get; set; } = "";
    public ObservableCollection<TreeNodeVm> Children { get; } = new();
}

---

Carousel

Displays one item at a time with animated transitions. Useful for image galleries, onboarding flows, or wizard steps.

Property	Type	Notes
ItemsSource	IEnumerable	Bound collection
SelectedIndex	int	TwoWay
SelectedItem	object	TwoWay
PageTransition	IPageTransition	Animation between items
IsVirtualized	bool	Only renders visible item

Built-in transitions: PageSlide, CrossFade, CompositePageTransition

<Carousel ItemsSource="{Binding Slides}"
          SelectedIndex="{Binding CurrentIndex}"
          IsVirtualized="True">
    <Carousel.PageTransition>
        <PageSlide Duration="0:0:0.4" Orientation="Horizontal"/>
    </Carousel.PageTransition>
    <Carousel.ItemTemplate>
        <DataTemplate x:DataType="vm:SlideVm">
            <Border Background="{Binding BackgroundColor}">
                <TextBlock Text="{Binding Title}" HorizontalAlignment="Center"
                           VerticalAlignment="Center" FontSize="24"/>
            </Border>
        </DataTemplate>
    </Carousel.ItemTemplate>
</Carousel>

<!-- Navigation buttons -->
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
    <Button Content="◀" Command="{Binding PreviousCommand}"/>
    <TextBlock Text="{Binding CurrentIndex}" VerticalAlignment="Center" Margin="16,0"/>
    <Button Content="▶" Command="{Binding NextCommand}"/>
</StackPanel>

---

Common Mistakes

Mistake	Fix
DataGrid not styled / missing	Add Avalonia.Controls.DataGrid NuGet and include Fluent.xaml style
DataGrid column Binding with x:DataType	Not supported in columns — use reflection {Binding}, not compiled
TreeView using plain DataTemplate	Use TreeDataTemplate with ItemsSource pointing to children; plain DataTemplate won't expand
ListBox.SelectedItems always empty	Requires SelectionMode="Multiple" (or Toggle) to populate
ItemsControl inside ScrollViewer inside StackPanel	StackPanel gives infinite height — items render but ScrollViewer won't scroll. Use Grid row with * height
Carousel flickering on fast navigation	Set IsVirtualized="True" and use CrossFade instead of PageSlide for smoother transitions
TextBlock not trimming	TextTrimming requires a MaxWidth constraint or a parent that constrains width