fix TextBox multiline selection with up/down keys till start/end of text

[rastislavsvoboda]

What does the pull request do?

Fix TextBox with multiline text during selection (Shift) with Up/Down keys

What is the current behavior?

In TextBox with multiline text while selecting (holding Shift):
pressing Down key on last line is not extending selection till the end of the last line text
pressing Up key on first line is not extending selection till the start of the first line text

What is the updated/expected behavior with this PR?

In TextBox with multiline text while selecting (holding Shift):
pressing Down key on last line will extend selection till the end of the last line text
pressing Up key on first line will extend selection till the start of the first line text

How was the solution implemented (if it's not obvious)?

Checklist

• Added unit tests (if possible)?
• Added XML documentation to any related classes?
• Consider submitting a PR to https://github.com/AvaloniaUI/avalonia-docs with user documentation

Breaking changes

Obsoletions / Deprecations

Fixed issues

[Gillibald]

You are changing public API. This can't be merged. The logic should also only expand the current selection to the end of the text when the current line is already added to the selection, and a second navigation in that direction is requested.

shiftSelection.mp4

[rastislavsvoboda]

You are changing public API. This can't be merged. The logic should also only expand the current selection to the end of the text when the current line is already added to the selection, and a second navigation in that direction is requested.

shiftSelection.mp4

Hi Benedikt

I'm not sure what you try to show on video
can you please more describe what I should I see / not see?

if I create
public void MoveCaretVerticalWhileSelecting(LogicalDirection direction)
and leave original untouched
would this be ok for you?

tb_selection_fix.mp4

[Gillibald]

The added logic to TextPresenter can be added to TextBox itself, so you do not need to add a isSelecting flag

[rastislavsvoboda]

The added logic to TextPresenter can be added to TextBox itself, so you do not need to add a isSelecting flag

I've tried...

[avaloniaui-bot]

You can test this PR using the following package version. 12.0.999-cibuild0056236-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[avaloniaui-bot]

You can test this PR using the following package version. 12.0.999-cibuild0056240-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[avaloniaui-bot]

You can test this PR using the following package version. 12.0.999-cibuild0056332-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[avaloniaui-bot]

You can test this PR using the following package version. 12.0.999-cibuild0056611-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[Gillibald]

LGTM

[avaloniaui-bot]

You can test this PR using the following package version. 12.0.999-cibuild0056673-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]