[Bug] Performance issue with ItemSizingStrategy on CollectionView

[Clancey]

Collection view does not add a default ItemSizingStrategy which defaults to MeasureAll.

This causes a major performance hit when using the GridLayout. With 100 items it adds a good 5 seconds to loading. It should default to MeasureFirstItem

Steps to Reproduce

Expected Behavior

Actual Behavior

Basic Information

• Version with issue:
• Last known good version:
• IDE:
• Platform Target Frameworks:
  • iOS:
  • Android:
  • UWP:
• Android Support Library Version:
• Nuget Packages:
• Affected Devices:

Screenshots

Reproduction Link

[jsuarezruiz]

James, Could you share a repro sample or more info (layout used in the DataTemplate, etc) ?. I have been doing tests #8325 and although, yes, the performance is better using MeasureFirstItem, I have not achieved very high differences in my tests.

[hartez]

@Clancey Which platform are we talking about here?

[davidortinau]

@hartez he showed me iOS. This is the app: https://github.com/Clancey/gMusic.Forms

Repro video here: https://www.twitch.tv/videos/501788807