MarkdownTextBlock Code Block Scrolling Fix

[WilliamABradley]

Added Scroll Hack to return Scrolling Inertia to the Parent ScrollViewer if it exists so that Code Blocks don't steal scroll.

Issue: #1881

PR Type

What kind of change does this PR introduce?

• Feature

What is the current behavior?

A Code Block ScrollViewer steals the Mouse Scroll Wheel from a Parent ScrollViewer outside of the MarkdownTextBlock, when the mouse cursor is over a Code Block.

What is the new behavior?

Violating fundamental concepts of C# to maintain scrolling inertia and prevent visible jankiness.

PR Checklist

Please check if your PR fulfills the following requirements:

• Tested code with current supported SDKs
• Tests for the changes have been added (for bug fixes / features) (if applicable)
• Header has been added to all new source files (run build/UpdateHeaders.bat)
• Contains NO breaking changes, eh.....

The Usability of the MarkdownTextBlock is improved, but the interaction is different (For the better).

[Vijay-Nirmal]

I have opened an issue (#2094) related to MarkdownTextBlock.

Scroll Bar in ScrollViewer is disappearing after a scroll with the mouse wheel

After this PR, We can scroll the code block using mouse wheel when the pointer is above the Scroll Bar area.

As we removed the scroll using mouse wheel feature in this PR, now the only option to scroll is by using scroll buttons. So we should fix that issue ASAP after this PR or in this PR.

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Update your branch and do this trick for ScrollViewer in RenderImage

[WilliamABradley]

@Vijay-Nirmal I have applied the fix to the Image Scrollviewer too. The scrollbar issue is out of our control (We didn't cause the issue) and will have to be dealt with at another time.

[WilliamABradley]

Note @nmetulev, this hasn't been tested with .NET Native (I can't seem to compile in Release for this App, some missing instruction error), this hack might need a Runtime directive.

[nmetulev]

Just tested it with a blank app in release mode and it works with .NET native - what app are you tying to build?

[WilliamABradley]

The Sample app fails with a Release mode compilation, I’m not sure if it is an insider thing or not. If it compiles and runs fine, that’s great. The issue is that .NET Native removed a lot of Reflection metadata. From: Nikola Metulev<mailto:notifications@github.com> Sent: Friday, 18 May 2018 6:17 PM To: Microsoft/WindowsCommunityToolkit<mailto:WindowsCommunityToolkit@noreply.github.com> Cc: William Bradley<mailto:williamabradley@outlook.com>; Author<mailto:author@noreply.github.com> Subject: Re: [Microsoft/WindowsCommunityToolkit] MarkdownTextBlock Code Block Scrolling Fix (#2093) Just tested it with a blank app in release mode and it works with .NET native - what app are you tying to build? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FMicrosoft%2FWindowsCommunityToolkit%2Fpull%2F2093%23issuecomment-390105876&data=02%7C01%7C%7C275c76016ad8450f5d1808d5bc87130c%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636622210675733104&sdata=3jwEyOJun6R75q5xVTplOZ6SFxgh21ZXge20D%2Btjny8%3D&reserved=0>, or mute the thread<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fnotifications%2Funsubscribe-auth%2FAFv1Kf7KyWAbyLMM9V43Ffokm667MWE6ks5tzmeJgaJpZM4T9oir&data=02%7C01%7C%7C275c76016ad8450f5d1808d5bc87130c%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636622210675733104&sdata=6f3pyeYI1xBh%2FYdTe1vrvIpBHttuV7LSCjC%2Fy5ECEqA%3D&reserved=0>.

[nmetulev]

I think that is an issue with the sample app - I'll take a look