[Macos] Fixed range null and text Out of bounds

[klousCan]

I temporarily use try catch to get out of bounds because I'm not very good at programming in oc

What does the pull request do?

Fixed range null and text Out of bounds

What is the current behavior?

Program crashes after entering Chinese characters

What is the updated/expected behavior with this PR?

Will not crash after entering Chinese
But try catch Solving the out of bounds problem is not a good idea

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

Fixes #14222

[klousCan]

@dotnet-policy-service agree

[avaloniaui-bot]

You can test this PR using the following package version. 11.2.999-cibuild0046423-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. 11.2.999-cibuild0046531-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[Gillibald]

I do not like the try catch block here. We should be able to make sure specified range fits into current attributed text.

[klousCan]

I do not like the try catch block here. We should be able to make sure specified range fits into current attributed text.

I also don't like try catch. Now I'm just fixing my existing problem, and I'm not very familiar with OC, you can fix it and merge this bug .Do I need to close this merge?

[Gillibald]

I could not reproduce the crash when I tried to fix this bug