Implementing WPF DropDownButtonAdv

The DropDownButtonAdv is a WPF dropdown button control that displays a popup menu when the arrow is clicked. It supports menu items with icons, data binding, command binding, configurable popup direction, resizing, multiline text, and full theme support.

Assembly: Syncfusion.Shared.WPF
Namespace: Syncfusion.Windows.Tools.Controls
XAML Schema: xmlns:syncfusion="http://schemas.syncfusion.com/wpf"

When to Use This Skill

User wants a button that opens a dropdown list of options
User needs a WPF dropdown button with icons, checkable items, or grouped items
User asks about DropDownButtonAdv, DropDownMenuGroup, DropDownMenuItem
User needs MVVM binding for dropdown menu items or command binding
User needs to control popup direction, resizing, or multiline label
User asks how to handle dropdown open/close events or item click events

Quick Start

xmlns:syncfusion="http://schemas.syncfusion.com/wpf"

<syncfusion:DropDownButtonAdv Label="Country" SizeMode="Normal" SmallIcon="Images/flag.png">
    <syncfusion:DropDownMenuGroup>
        <syncfusion:DropDownMenuItem HorizontalAlignment="Left" Header="India">
            <syncfusion:DropDownMenuItem.Icon>
                <Image Source="Images/india.png"/>
            </syncfusion:DropDownMenuItem.Icon>
        </syncfusion:DropDownMenuItem>
        <syncfusion:DropDownMenuItem HorizontalAlignment="Left" Header="France"/>
        <syncfusion:DropDownMenuItem HorizontalAlignment="Left" Header="Germany"/>
    </syncfusion:DropDownMenuGroup>
</syncfusion:DropDownButtonAdv>

// C# equivalent
DropDownButtonAdv button = new DropDownButtonAdv();
button.Label = "Country";
button.SizeMode = SizeMode.Normal;
button.SmallIcon = new BitmapImage(new Uri("Images/flag.png", UriKind.RelativeOrAbsolute));
DropDownMenuGroup menu = new DropDownMenuGroup();
menu.Items.Add(new DropDownMenuItem { Header = "India", HorizontalAlignment = HorizontalAlignment.Left });
button.Content = menu;

Common Patterns

Goal	Approach
Static menu items	Declare `DropDownMenuItem` directly inside `DropDownMenuGroup`
Dynamic items from data	Bind `DropDownMenuGroup.ItemsSource` + use `ItemTemplate`
MVVM command on item click	Set `Command` + `CommandParameter` on `DropDownMenuItem`
Popup opens below-left	`DropDirection="BottomLeft"` (default)
Large button with label wrapping	`SizeMode="Large"` + `IsMultiLine="True"`
Checkable items	`IsCheckable="True"` on `DropDownMenuItem`
Custom UIElement in menu	Use `DropDownMenuGroup.MoreItems` property
Scrollable long list	Set `MaxHeight` + `ScrollBarVisibility="Visible"` on group
Resizable popup	`IsResizable="True"` on `DropDownMenuGroup`

Key Properties

Property	Type	Description
`Label`	`string`	Button text label
`SizeMode`	`SizeMode`	Small / Normal / Large
`SmallIcon`	`ImageSource`	Icon for Small and Normal modes
`LargeIcon`	`ImageSource`	Icon for Large mode
`IconTemplate`	`DataTemplate`	Vector/path icon template (overrides image icons)
`IconTemplateSelector`	`DataTemplateSelector`	Conditionally select icon template
`IconWidth` / `IconHeight`	`double`	Icon dimensions
`DropDirection`	`DropDirection`	Popup position (default: BottomLeft)
`IsMultiLine`	`bool`	Multi-line label (Large mode only)
`DropDownMenuGroup.ItemsSource`	`IEnumerable`	Data-bound menu items
`DropDownMenuGroup.IconBarEnabled`	`bool`	Show vertical icon bar
`DropDownMenuGroup.ScrollBarVisibility`	`ScrollBarVisibility`	Scrollbar in popup
`DropDownMenuGroup.IsResizable`	`bool`	Resize gripper on popup
`DropDownMenuGroup.MoreItems`	`ObservableCollection<UIElement>`	Custom bottom items
`DropDownMenuItem.IsCheckable`	`bool`	Allow check/uncheck
`DropDownMenuItem.Command`	`ICommand`	MVVM command
`DropDownMenuItem.CommandParameter`	`object`	Command parameter