[UWP] CollectionView disable caching item templates with DataTemplateSelector

[nk221]

Description of Change

Issue #14236 seems related to #11732 and appeared after pull request #11043.

There we are trying to reuse an ItemTemplate but it doesn't work when CollectionView uses a DataTemplateSelector instead of an ItemTemplate directly.

The solution is not perfect, but it returns CollectionView to working condition as it was before #11043. Template caching still works for an ItemTemplate and disabled when we use a DataTemplateSelector.

That would be great to have a template cache for templates selected by DataTemplateSelector, but I don’t know how to do it exactly. I have tried to cache a renderer with a template as a key, it works incorrectly. Currently, I have no time for further experiments. If you have any advice on how to do it the right way please let me know. I will try to implement it later.

Issues Resolved

• fixes [Bug][UWP] CollectionView does not call DataTemplateSelector #14236
• fixes [Bug] UWP CollectionView not displaying content, or including incorrect content #11732

API Changes

None

Platforms Affected

• UWP

Behavioral/Visual Changes

None

Before/After Screenshots

Not applicable

Testing Procedure

• Launch Control Gallery and navigate to issue G14236.
• Click on the button to add items to ItemSource
• Scroll down, click, scroll down...

Before fix on the second or third click, we get items with incorrect templates and with 0 in RequestTemplateCount.
After the fix, all items have correct templates.

PR Checklist

• Targets the correct branch
• Tests are passing (or failures are unrelated)

[jfversluis]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).

[jfversluis]

Thanks for your contribution @nk221 look for it in the next service release!