avalonia docs

ComboBox

A drop-down list control.

Common Properties

Property Description
SelectedIndex Gets or sets the index of the selected item.
SelectedItem Gets or sets the selected item.
SelectedItems Gets the selected items.
AutoScrollToSelectedItem Gets or sets a value indicating whether to automatically scroll to newly selected items.
SelectionMode Gets or sets the selection mode.
IsDropDownOpen Gets or sets a value indicating whether the dropdown is currently open.
MaxDropDownHeight Gets or sets the maximum height for the dropdown list.

Reference

ComboBox

Source code

ComboBox.cs

Examples

Basic ComboBox

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="AvaloniaAppTemplate.MainWindow"
        Title="AvaloniaAppTemplate">
    <StackPanel>
        <ComboBox SelectedIndex="0">
            <ComboBoxItem>Inline Items</ComboBoxItem>
            <ComboBoxItem>Inline Item 2</ComboBoxItem>
            <ComboBoxItem>Inline Item 3</ComboBoxItem>
            <ComboBoxItem>Inline Item 4</ComboBoxItem>
        </ComboBox>
    </StackPanel>
</Window>

ComboBox with custom item templates

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="AvaloniaAppTemplate.MainWindow"
        Title="AvaloniaAppTemplate">
    <StackPanel>
        <ComboBox SelectedIndex="0">
            <ComboBoxItem>
                <Panel>
                    <Rectangle Fill="{DynamicResource ThemeAccentBrush}"/>
                    <TextBlock Margin="8">Control Items</TextBlock>
                </Panel>
            </ComboBoxItem>
            <ComboBoxItem>
                <Ellipse Width="50" Height="50" Fill="Yellow"/>
            </ComboBoxItem>
            <ComboBoxItem>
                <TextBox Text="TextBox"/>
            </ComboBoxItem>
      </ComboBox>
    </StackPanel>
</Window>

ComboBox with binding

This example binds the fonts installed to a ComboBox

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="AvaloniaAppTemplate.MainWindow"
        Title="AvaloniaAppTemplate">
    <StackPanel>
        <ComboBox x:Name="fontComboBox"  SelectedIndex="0">
            <ComboBox.ItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding Name}" FontFamily="{Binding}" />
                </DataTemplate>
            </ComboBox.ItemTemplate>
       </ComboBox>
    </StackPanel>
</Window>

With this code behind:

var fontComboBox = this.Find<ComboBox>("fontComboBox");
fontComboBox.Items = FontManager.Current.GetInstalledFontFamilyNames().Select(x => new FontFamily(x));
fontComboBox.SelectedIndex = 0;