Expander Class

Definition

Namespace:

Microsoft.UI.Xaml.Controls

Represents a control that displays a header and has a collapsible body that displays content.

This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).

/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
/// [Windows.Foundation.Metadata.ContractVersion(Microsoft.UI.Xaml.XamlContract, 65536)]
class Expander : ContentControl

[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
[Windows.Foundation.Metadata.ContractVersion(typeof(Microsoft.UI.Xaml.XamlContract), 65536)]
public class Expander : ContentControl

Public Class Expander
Inherits ContentControl

Inheritance

ContentControl

Expander

Attributes

MarshalingBehaviorAttribute ThreadingAttribute ContractVersionAttribute

Examples

Tip

For more info, design guidance, and code examples, see Expander.

Open the WinUI 2 Gallery app and see the Expander in action.

The WinUI 2 Gallery app includes interactive examples of most WinUI 2 controls, features, and functionality. Get the app from the Microsoft Store or get the source code on GitHub.

Remarks

Tip

For more info, design guidance, and code examples, see Expander overview.

Use an Expander to focus on the most important content when display space is limited. The Expander control lets you show or hide less important content that's related to a piece of primary content that's always visible. Items contained in the Header are always visible. The user can expand and collapse the content area, where secondary content is displayed, by interacting with the header. When the content area is expanded, it pushes other UI elements out of the way; it does not overlay other UI. The Expander can expand upwards or downwards.

Both the Header and Content areas can contain any content, from simple text to complex UI layouts.

Control style and template

You can modify the default Style and ControlTemplate to give the control a unique appearance. For information about modifying a control's style and template, see XAML styles. The default style, template, and resources that define the look of the control are included in the generic.xaml file. For design purposes, generic.xaml is installed with the WinUI (Microsoft.UI.Xaml) NuGet package. By default, this location is \Users\<username>\.nuget\packages\microsoft.ui.xaml\<version>\lib\uap10.0\Microsoft.UI.Xaml\Themes\generic.xaml. Styles and resources from different versions of WinUI might have different values.

XAML also includes resources that you can use to modify the colors of a control in different visual states without modifying the control template. Modifying these resources is preferred to setting properties such as Background and Foreground. For more info, see the Light-weight styling section of the XAML styles article.

Constructors

Expander()

Initializes a new instance of the Expander class. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).

Properties

ExpandDirection	Gets or sets a value that indicates the direction in which the content area expands. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).
ExpandDirectionProperty	Identifies the ExpandDirection dependency property. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).
Header	Gets or sets the XAML content that is displayed in the header of the Expander. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).
HeaderProperty	Identifies the Header dependency property. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).
HeaderTemplate	Gets or sets the data template for the Expander.Header. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).
HeaderTemplateProperty	Identifies the HeaderTemplate dependency property. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).
HeaderTemplateSelector	Gets or sets a reference to a custom DataTemplateSelector logic class that returns a template to apply to the Header. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).
HeaderTemplateSelectorProperty	Identifies the HeaderTemplateSelector dependency property. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).
IsExpanded	Gets or sets a value that indicates whether the content area of the Expander is shown. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).
IsExpandedProperty	Identifies the IsExpanded dependency property. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).
TemplateSettings	Gets an object that provides calculated values that can be referenced as TemplatedParent sources when defining templates for an Expander. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).

Events

Collapsed	Occurs when the content area of the Expander is hidden. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).
Expanding	Occurs when the content area of the Expander starts to be shown. This documentation applies to WinUI 2 for UWP (for WinUI in the Windows App SDK, see the Windows App SDK namespaces).

See also

• Expander overview