[iOS/Android/UWP/Shared] Fix handling of orphaned table child elements

[paulcam206]

Related Issue

Fixes #6393

Description

TableCell and TableRow weren't restricted to only being parseable from within the context of a Table element. The fix here was to partially emulate the behavior of ColumnSet, where it's the containing element's responsibility to parse its children (rather than deferring that responsibility to the parser like we do for more generic elements like Container. The right way to do this was to use the more generic CollectionTypeElement class for Table in order to use DeserializeChildren. Unfortunately, CollectionTypeElement also contained other styling properties/methods unsuitable for Table, so it was split out into CollectionCoreElement (an element that is responsible for deserializing its children) and StyledCollectionElement, which adds common styling stuff.

While doing this I also noticed that the JS renderer allows implicit element types on the parsed children of Table. In other words, this is reasonable and valid:

Sample implied type card

{
	"type": "AdaptiveCard",
	"$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
	"version": "1.5",
	"body": [
		{
			"type": "Table",
			"columns": [
				{
					"width": 1
				}
			],
			"rows": [
				{
					"cells": [
						{
							"items": [
								{
									"type": "TextBlock",
									"text": "Text goes here."
								}
							]
						}
					]
				}
			]
		}
	]
}

I fixed this up as well following the existing ColumnSet/Column pattern, which validate the types if present, but uses the inferred element type otherwise.

After this, it was just a matter of getting UWP, iOS, and Android building properly and validating the rendering behavior.

Sample Card

I added two new test cards -- one containing orphaned TableRow and TableCell elements (which should parse as Unknown elements and have no rendering) and another containing the exact card from above.

Screenshots

UWP

Orphaned elements:

Implied type:

Android

Orphaned elements:

Implied type:

iOS

Orphaned elements:

Implied type:

How Verified

• new unit tests and test cards
• build/manual test across UWP, iOS, and Android

Microsoft Reviewers: Open in CodeFlow