Feature name

Expander updated to support animation via a new ExpanderAnimationBehavior

public partial class ExpanderAnimationBehavior : BaseBehavior<Views.Expander>, IExpansionController
{
    [BindableProperty] public partial Easing CollapsingEasing { get; set; } = Easing.Linear;
    [BindableProperty] public partial uint CollapsingLength { get; set; } = 250u;
    [BindableProperty] public partial Easing ExpandingEasing { get; set; } = Easing.Linear;
    [BindableProperty] public partial uint ExpandingLength { get; set; } = 250u;
    // ...
}

Link to discussion

#1628

Progress tracker

• Android Implementation
• iOS Implementation
• MacCatalyst Implementation
• Windows Implementation
• Tizen Implementation
• Unit Tests
• Samples
• Documentation (TODO)

Summary

This issue and the corresponding PR is to continue a conversation that started in the discussion forums on how we may introduce animations to the Expander component.

Motivation

The Expander component could be improved to support animation.

Detailed Design

[Feb 15, 2025, Original Design]
[April 5, 2025, Refactor/Rewrite]

[March 2, 2026, Refactor/Rewrite]

Wrap the user's Expander.Content inside a new Expander.ContentHost (ContentView) so that we can implement expanding/collapsing animation by manipulating Expander.ContentHost.HeightRequest.

Usage:

<toolkit:Expander>
    <!-- Expander.Header -->
    <toolkit:Expander.Behaviors>
        <toolkit:ExpanderAnimationBehavior>
    </toolkit:Expander.Behaviors>
    <!-- Expander.Content -->
</toolkit:Expander>

Drawbacks

No response

Unresolved Questions

No response