(Marquee) When Behavior="Looping" and Direction is set to vertical, it causes “Layout cycle detected. Layout could not complete.”

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Issue 类型
缺陷
描述清晰度
基本清楚
活跃度
停滞
技术栈
csharp
领域
frontend

调研方向

使用提供的 Marquee 标记并设置 Behavior="Looping" 和 Direction="Down"，重现该崩溃。阅读 components/Marquee/src/Marquee.xaml、Marquee.cs 的第 69、211 和 241 行，以及 Marquee.Events.cs 的第 36 和 62 行，重点关注 SizeChanged 订阅和 segment 可见性的变化。完成的标准是垂直 looping 不再导致 layout 循环或崩溃，并且 container 不会被重复订阅。

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描述

bug :bug:
Describe the bug

https://github.com/CommunityToolkit/Labs-Windows/blob/acda1c3df1b71dbf77bc80a0544eae7955398d49/components/Marquee/src/Marquee.xaml#L9

https://github.com/CommunityToolkit/Labs-Windows/blob/acda1c3df1b71dbf77bc80a0544eae7955398d49/components/Marquee/src/Marquee.Events.cs#L62

https://github.com/CommunityToolkit/Labs-Windows/blob/acda1c3df1b71dbf77bc80a0544eae7955398d49/components/Marquee/src/Marquee.cs#L241

https://github.com/CommunityToolkit/Labs-Windows/blob/acda1c3df1b71dbf77bc80a0544eae7955398d49/components/Marquee/src/Marquee.cs#L211

I noticed that the Marquee control crashes. After debugging, I believe the SizeChanged event causes the visibility of segment2 to change. Since the control’s default vertical alignment is set to Top, this triggers another SizeChanged event, resulting in an infinite loop.
Setting VerticalAlignment="Stretch" allows it to work correctly, but this is not a real solution.

In addition, I noticed that _marqueeContainer is repeatedly subscribing to the SizeChanged event.
https://github.com/CommunityToolkit/Labs-Windows/blob/acda1c3df1b71dbf77bc80a0544eae7955398d49/components/Marquee/src/Marquee.cs#L69

https://github.com/CommunityToolkit/Labs-Windows/blob/acda1c3df1b71dbf77bc80a0544eae7955398d49/components/Marquee/src/Marquee.Events.cs#L36

Steps to reproduce
<labs:Marquee
     Behavior="Looping"
     Content="Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua."
     Direction="Down"
     FontSize="18"
     RepeatBehavior="Forever"
     Speed="200" />


Just setting Behavior="Looping" is enough to trigger the crash.
Expected behavior

This shouldn't cause the program to crash.

Screenshots
Image
Code Platform
  • UWP
  • WinAppSDK / WinUI 3
  • Web Assembly (WASM)
  • Android
  • iOS
  • MacOS
  • Linux / GTK
Windows Build Number
  • Windows 10 1809 (Build 17763)
  • Windows 10 1903 (Build 18362)
  • Windows 10 1909 (Build 18363)
  • Windows 10 2004 (Build 19041)
  • Windows 10 20H2 (Build 19042)
  • Windows 10 21H1 (Build 19043)
  • Windows 11 21H2 (Build 22000)
  • Other (specify)
Other Windows Build number

No response

App minimum and target SDK version
  • Windows 10, version 1809 (Build 17763)
  • Windows 10, version 1903 (Build 18362)
  • Windows 10, version 1909 (Build 18363)
  • Windows 10, version 2004 (Build 19041)
  • Other (specify)
Other SDK version

No response

Visual Studio Version

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Visual Studio Build Number

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Device form factor

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Additional context

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