UWP renderer crashes if HTTP image cannot be found

If an image can’t be found, like bad HTTP link or anything, the UWP renderer crashes uncatchably and crashes the parent app.

Repro payload

{
	"$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
	"type": "AdaptiveCard",
	"version": "0.5",
	"body": [
		{
			"type": "Image",
			"url": "http://adaptivecards.io/assets/Closed%20bug%2092x92.png",
			"size": "medium"
		}
	]
}

[riarenas]

This issue is popping up more and more frequently. There are a few corner cases that are not captured with Andrew’s fix, such as:

• Empty image URL.
• Invalid URL format,
• Lack of internet connectivity.
• No internet capability in calling app.

I’m working on top of Andrew’s changes to address these issues. We have discussed a rework on how we handle image downloads, but that will require more comprehensive code changes. For now I’m patching our existing image downloader so that if one of this issues is present, the card won’t be rendered at all. It’s not ideal behavior, but I belive it’s the best thing we can do for now to fix a lot of the issues our consumers have been reporting.

[andrewleader]

Nice! Agreed, we can always add a new method like RenderWithErrorInfo or something that will provide a half-rendered card with error info about failed images/etc. For now just failing completely is good enough for our existing scenarios.