Avalonia/samples/ControlCatalog/Pages/TabControlPage.xaml

<UserControl
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Class="ControlCatalog.Pages.TabControlPage"
    xmlns="https://github.com/avaloniaui"
    xmlns:viewModels="using:ControlCatalog.ViewModels"
    x:DataType="viewModels:TabControlPageViewModel">
    <DockPanel Classes.WithContentTemplates="{Binding IsChecked, ElementName=UseContentTemplates}">
        <DockPanel.Styles>
            <Style Selector="DockPanel.WithContentTemplates">
                <Style Selector="^ TabItem">
                    <Setter Property="ContentTemplate">
                        <DataTemplate x:DataType="x:Object">
                            <Border BorderBrush="Red" BorderThickness="10">
                                <ContentPresenter Content="{Binding}"/>
                            </Border>
                        </DataTemplate>
                    </Setter>
                </Style>
                <Style Selector="^ TabControl">
                    <Setter Property="ContentTemplate">
                        <DataTemplate>
                            <TextBlock Text="This template should be overriden by each TabItem's template."/>
                        </DataTemplate>
                    </Setter>
                </Style>
            </Style>
        </DockPanel.Styles>
        <TextBlock 
            DockPanel.Dock="Top" 
            Classes="h2"
            Text="A tab control that displays a tab strip along with the content of the selected tab"
            Margin="4">
        </TextBlock>
        <Grid 
            ColumnDefinitions="*,*" 
            RowDefinitions="*,100">
            <DockPanel
                Grid.Column="0"
                Margin="4">
                <TextBlock
                    DockPanel.Dock="Top"
                    Classes="h1"
                    Text="From Inline TabItems">
                </TextBlock>
                <TabControl
                    Margin="0 16"
                    TabStripPlacement="{Binding TabPlacement}">
                    <TabItem Header="_Arch">
                        <StackPanel Orientation="Vertical" Spacing="8">
                            <TextBlock>This is the first page in the TabControl.</TextBlock>
                            <Image Source="/Assets/delicate-arch-896885_640.jpg" Width="300"/>
                        </StackPanel>
                    </TabItem>
                    <TabItem Header="_Leaf">
                        <StackPanel Orientation="Vertical" Spacing="8">
                            <TextBlock>This is the second page in the TabControl.</TextBlock>
                            <Image Source="/Assets/maple-leaf-888807_640.jpg" Width="300"/>
                        </StackPanel>
                    </TabItem>
                    <TabItem Header="_Disabled" IsEnabled="False">
                        <TextBlock>You should not see this.</TextBlock>
                    </TabItem>
                </TabControl>
            </DockPanel>
            <DockPanel
                Grid.Column="1"
                Margin="4">
                <TextBlock
                    DockPanel.Dock="Top"
                    Classes="h1"
                    Text="From DataTemplate">
                </TextBlock>
                <TabControl
                    ItemsSource="{Binding Tabs}"
                    Margin="0 16"
                    DisplayMemberBinding="{Binding Header, x:DataType=viewModels:TabControlPageViewModelItem}"
                    TabStripPlacement="{Binding TabPlacement}">
                    <TabControl.DataTemplates>
                        <DataTemplate x:DataType="viewModels:TabControlPageViewModelItem">
                            <StackPanel Orientation="Vertical" Spacing="8">
                                <TextBlock Text="{Binding Text}"/>
                                <Image Source="{Binding Image}" Width="300"/>
                            </StackPanel>
                        </DataTemplate>
                    </TabControl.DataTemplates>
                    <TabControl.Styles>
                        <Style Selector="TabItem" x:DataType="viewModels:TabControlPageViewModelItem">
                            <Setter Property="IsEnabled" Value="{Binding IsEnabled}"/>
                        </Style>
                    </TabControl.Styles>
                </TabControl>
            </DockPanel>
            <StackPanel
                Grid.Row="1"
                Grid.ColumnSpan="2"
                Orientation="Horizontal"
                Spacing="8"
                HorizontalAlignment="Center"
                VerticalAlignment="Center">
                <TextBlock VerticalAlignment="Center">Tab Placement:</TextBlock>
                <ComboBox SelectedIndex="{Binding TabPlacement, Mode=TwoWay}" Width="100">
                    <ComboBoxItem>Left</ComboBoxItem>
                    <ComboBoxItem>Bottom</ComboBoxItem>
                    <ComboBoxItem>Right</ComboBoxItem>
                    <ComboBoxItem>Top</ComboBoxItem>
                </ComboBox>
                <CheckBox Name="UseContentTemplates">Set TabItem.ContentTemplate</CheckBox>
            </StackPanel>
        </Grid>
    </DockPanel>
</UserControl>