XAML代碼：

<Popup x:Name="popupStrategy" StaysOpen="False" PopupAnimation="Scroll" Width="190" MaxHeight="300" AllowsTransparency="True">
    <Border Background="#0c5ab0" BorderThickness="1" BorderBrush="#1992d6">
        <ItemsControl x:Name="itemsCtrlStrategy" Grid.Row="1" Margin="0 5 0 0"
 
>
            <ItemsControl.Template>
                <ControlTemplate>
                    <ScrollViewer HorizontalScrollBarVisibility="Auto" MinHeight="{Binding ElementName=itemsCtrlStrategy,Path=ActualHeight}" MinWidth="{Binding ElementName=itemsCtrlStrategy, Path=ActualWidth}
 
">
                        <ItemsPresenter></ItemsPresenter>
                    </ScrollViewer>
                </ControlTemplate>
            </ItemsControl.Template>
            <ItemsControl.ItemsPanel>
                <ItemsPanelTemplate>
                    <
 
StackPanel/>
                </ItemsPanelTemplate>
            </ItemsControl.ItemsPanel>
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal" Margin="5 0 5 5" Background="#00234E">
                        <Button x:Name="btnStrategySel" Click="btnStrategySel_Click_1" CommandParameter="{Binding}" Width="120" Margin="5" VerticalAlignment="Center" HorizontalAlignment="Center">
                            <Button.Template>
                                <ControlTemplate>
                                    <TextBlock Text="{Binding Info.STRATEGYNAME}" ToolTip="{Binding Info.STRATEGYNAME}" Width="120" Foreground="#1ba4f6" VerticalAlignment="Center" HorizontalAlignment="Center"></TextBlock>
                                </ControlTemplate>
                            </Button.Template>
                        </Button>
                        <Button x:Name="btnStrategyDel" Margin="5" CommandParameter="{Binding}" Click="btnStrategyDel_Click_1" Height="12" Width="12" VerticalAlignment="Center" HorizontalAlignment="Center">
                            <Button.Template>
                                <ControlTemplate>
                                    <Image Name="img" Width="12" Height="12" VerticalAlignment="Center" Source="/SunCreate.CombatPlatform.Client.Resources;component/Image/CaseExportStrategy/刪除.png"></Image>
                                </ControlTemplate>
                            </Button.Template>
                        </Button>
                        <Button x:Name="btnStrategyEdit" Margin="5" CommandParameter="{Binding}" Click="btnStrategyEdit_Click_1" Height="12" Width="12" VerticalAlignment="Center" HorizontalAlignment="Center">
                            <Button.Template>
                                <ControlTemplate>
                                    <Image Name="img" Width="12" Height="12" VerticalAlignment="Center" Source="/SunCreate.CombatPlatform.Client.Resources;component/Image/CaseExportStrategy/編輯.png"></Image>
                                </ControlTemplate>
                            </Button.Template>
                        </Button>
                    </StackPanel>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>
    </Border>
</Popup>

後臺代碼：

itemsCtrlStrategy.ItemsSource = strategyViewModelList;

popupStrategy.PlacementTarget = sender as Button;
popupStrategy.Placement = PlacementMode.Bottom;
popupStrategy.IsOpen = true;

效果圖：

WPF 自定義下拉列表