WPF_Practice/PacticeSolution/ComboBoxSample/MainWindow.xaml

<Window x:Class="ComboBoxSample.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        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"
        xmlns:local="clr-namespace:ComboBoxSample"
        mc:Ignorable="d"
        Title="MainWindow" Height="400" Width="400">
    <Window.DataContext>
        <local:ColorList/>
    </Window.DataContext>
    
    <StackPanel>
        <Label Content="Color" HorizontalAlignment="Center" FontWeight="Bold"/>
        <ComboBox Width="200" HorizontalAlignment="Center" SelectedIndex="0">
            <ComboBoxItem>
                <StackPanel Orientation="Horizontal">
                    <Ellipse Fill="Red" Width="15" Height="15" Margin="0 0 5 0"/>
                    <TextBlock Text="Red"/>
                </StackPanel>
            </ComboBoxItem>
            <ComboBoxItem>
                <StackPanel Orientation="Horizontal">
                    <Ellipse Fill="Green" Width="15" Height="15" Margin="0 0 5 0"/>
                    <TextBlock Text="Green"/>
                </StackPanel>
            </ComboBoxItem>
            <ComboBoxItem Content="Blue"/>
            <ComboBoxItem Content="Orange"/>
        </ComboBox>
        <Label Content="Color from list" HorizontalAlignment="Center" FontWeight="Bold"/>
        <ComboBox Width="200" ItemsSource="{Binding}" SelectedIndex="0">
            <ComboBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <Ellipse Fill="{Binding}" Width="15" Height="15" Margin="0 0 5 0"/>
                        <TextBlock Text="{Binding}"/>
                    </StackPanel>
                </DataTemplate>
            </ComboBox.ItemTemplate>
        </ComboBox>
    </StackPanel>
</Window>