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">
    <DockPanel>
        <TextBlock 
            DockPanel.Dock="Top" 
            Classes="h1"
            Text="TabControl"
            Margin="4">           
        </TextBlock>
        <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
                    Items="{Binding Tabs}"
                    Margin="0 16"
                    TabStripPlacement="{Binding TabPlacement}">
                    <TabControl.ItemTemplate>
                        <DataTemplate>
                            <TextBlock
                                Text="{Binding Header}">
                            </TextBlock>
                        </DataTemplate>
                    </TabControl.ItemTemplate>
                    <TabControl.ContentTemplate>
                        <DataTemplate>
                            <StackPanel Orientation="Vertical" Spacing="8">
                                <TextBlock Text="{Binding Text}"/>
                                <Image Source="{Binding Image}" Width="300"/>
                            </StackPanel>
                        </DataTemplate>
                    </TabControl.ContentTemplate>
                    <TabControl.Styles>
                        <Style Selector="TabItem">
                            <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>
                <DropDown SelectedIndex="{Binding TabPlacement, Mode=TwoWay}">
                    <DropDownItem>Left</DropDownItem>
                    <DropDownItem>Bottom</DropDownItem>
                    <DropDownItem>Right</DropDownItem>
                    <DropDownItem>Top</DropDownItem>
                </DropDown>
            </StackPanel>
        </Grid>
    </DockPanel>
</UserControl>