For All `CommunityToolkit.Maui.Behavior`s, Ensure `BindingContext` Is Automatically Set to the Attached View's `BindingContext` by TheCodeTraveler · Pull Request #1791 · CommunityToolkit/Maui

TheCodeTraveler · 2024-04-03T01:47:18Z

Description of Change

The goal of this Pull Request is to ensure that every Behavior in CommunityToolkit.Maui.Behavior automatically set's the its BindingContext to match the BindingContext of the attached View.

This PR creates/updates the following classes/interfaces:

ICommunityToolkitBehavior - an interface meant for internal consumption, used to align the functionality of BaseBehavior and BasePlatformBehavior

protected TView? View { get; set; }

internal bool TrySetBindingContextToAttachedViewBindingContext();
internal bool TryRemoveBindingContext();
internal void AssignViewAndBingingContext(TView bindable);
internal void UnassignViewAndBingingContext(TView bindable);
protected void OnViewPropertyChanged(object? sender, PropertyChangedEventArgs e)
protected void OnViewPropertyChanged(TView sender, PropertyChangedEventArgs e);

BaseBehavior : ICommunityToolkitBehavior
- BaseBehavior now implements ICommunityToolkitBehavior
BasePlatformBehavior<TView> : BasePlatformBehavior<TView, PlatformView> where TView : Element
- Uses the default PlatformView for each operating system
BasePlatformBehavior<TView, TPlatformView> : PlatformBehavior<TView, TPlatformView>, ICommunityToolkitBehavior<TView> where TView : Element where TPlatformView : class

Linked Issues

Fixes Touch Behavior Should Automatically Set BindingContext #1785

PR Checklist

Has a linked Issue, and the Issue has been approved(bug) or Championed (feature/proposal)
Has tests (if omitted, state reason in description)
Has samples (if omitted, state reason in description)
Rebased on top of main at time of PR
Changes adhere to coding standard
Documentation created or updated: https://github.com/MicrosoftDocs/CommunityToolkit/pulls

Additional information

The unit tests for BasePlatformBehavior can't test OnAttachedTo() because OnAttachedTo() is only called in platform-specific code for Microsoft.Maui.Controls.PlatformBehavior.

I also updated the Unit Tests to use Collection Expressions for a small performance bump.

pictos

it looks a lot of work, great that you could fit it soo fast! I've some points there

Axemasta · 2024-04-03T08:17:42Z

Does the BaseBehavior need to account for being attached to multiple VisualElements? Currently with the TouchBehavior it will get wierd... all views attached will receive inputs but only the last view the behavior was added to will be animated.

Since specifically the TouchBehavior needs to be applied 1:1 (behavior : view) should the BaseBehavior have a way of preventing attaching to multiple views?

TheCodeTraveler · 2024-04-03T18:19:22Z

Does the BaseBehavior need to account for being attached to multiple VisualElements? Currently with the TouchBehavior it will get weird... all views attached will receive inputs but only the last view the behavior was added to will be animated.

Since specifically the TouchBehavior needs to be applied 1:1 (behavior : view) should the BaseBehavior have a way of preventing attaching to multiple views?

Good question - yes! I followed the existing pattern I found in BaseBehavior and extended it to BasePlatformBehavior via ICommunityToolkitBehavior. It'll automatically set the Behavior.BindingContext to match the BindingContext of the first VisualElement it is attached to. If the same Behavior is then attached to another VisualElement, it will keep the BindingContext from the first VisualElement.

Co-authored-by: Pedro Jesus <[email protected]>

…ttps://github.com/CommunityToolkit/Maui into Update-All-Behaviors-to-Inherit-from-`BaseBehavior`

TheCodeTraveler · 2024-04-03T22:29:56Z

Ok gang! I think this is ready to go.

I refactored a couple things just now:

In ICommunityToolkitBehavior, changed internal OnViewPropertyChanged(object? sender, PropertyChangedEventArgs e) -> protected OnViewPropertyChanged(object? sender, PropertyChangedEventArgs e)
Implemented CollectionExpressions for Unit Tests

tranb3r · 2024-04-05T13:36:29Z

@brminnick @pictos
I think there is a regression in 8.0.1.
In a CollectionView, the BindingContext is not set correctly when using TouchBehavior. When I tap on an item, the command from another item is executed. Maybe because of weird recycling stuff?
I did not have this problem with 8.0.0 and setting the BindingContext manually.
Also, with 8.0.1, even if I set the BindingContext manually, it does not fix the issue.
Could you please double-check? I do not have the time to build a repro right now, but it's easy to reproduce.

TheCodeTraveler added 12 commits April 2, 2024 13:57

Add BasePlatformBehavior

31cc74f

Create BaseBehaviorTest

966ff10

Use BaseBehaviorTest

e743eb6

Update Binding Logic

ffbe1f3

dotnet format

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Move + Rename Files

85c2f8f

Add Missing Calls to Base Virtual Methods

b6fb04f

Remove Manual BindingContexts

eeafe53

Update Unit Tests

4fe9a28

Use View for Element

2546a19

dotnet format

69e4bec

dotnet format

516f6dc

TheCodeTraveler requested review from bijington and pictos April 3, 2024 01:47

TheCodeTraveler commented Apr 3, 2024

View reviewed changes

Comment thread src/CommunityToolkit.Maui/Behaviors/BaseBehavior.shared.cs

TheCodeTraveler commented Apr 3, 2024

View reviewed changes

Comment thread src/CommunityToolkit.Maui/Behaviors/ICommunityToolkitBehavior.shared.cs

pictos reviewed Apr 3, 2024

View reviewed changes

This was referenced Apr 3, 2024

Added Touch Behavior Migration Guide MicrosoftDocs/CommunityToolkit#399

Merged

[BUG] TouchBehavior crash #1783

Closed

Update src/CommunityToolkit.Maui/Behaviors/BaseBehavior.shared.cs

d3558db

Co-authored-by: Pedro Jesus <[email protected]>

TheCodeTraveler added the needs discussion Discuss it on the next Monthly standup label Apr 3, 2024

TheCodeTraveler added 5 commits April 3, 2024 11:30

Use PropertyName

65e6798

Use OnViewPropertyChanged

b94c1c6

Merge branch 'Update-All-Behaviors-to-Inherit-from-BaseBehavior' of h…

01b90aa

…ttps://github.com/CommunityToolkit/Maui into Update-All-Behaviors-to-Inherit-from-`BaseBehavior`

Use Trace.Writeline on failure

146b893

Add private protected constructors

f98baa6

TheCodeTraveler requested a review from pictos April 3, 2024 18:52

VladislavAntonyuk previously approved these changes Apr 3, 2024

View reviewed changes

TheCodeTraveler added 2 commits April 3, 2024 14:34

Change OnViewPropertyChanged from internal -> protected

a910a5f

Update to CollectionExpressions

4360ccc

TheCodeTraveler dismissed VladislavAntonyuk’s stale review via 4360ccc April 3, 2024 21:35

TheCodeTraveler added 2 commits April 3, 2024 14:57

Update All Unit Test to use Collection Expressions

749b5a3

Fix XML Comments

a641406

TheCodeTraveler enabled auto-merge (squash) April 3, 2024 22:11

pictos approved these changes Apr 3, 2024

View reviewed changes

TheCodeTraveler merged commit d7a84df into main Apr 3, 2024

TheCodeTraveler deleted the Update-All-Behaviors-to-Inherit-from-`BaseBehavior` branch April 3, 2024 23:15

TheCodeTraveler mentioned this pull request Apr 4, 2024

Update Touch Behavior Sample #1784

Merged

6 tasks

tranb3r mentioned this pull request Apr 8, 2024

[BUG][Regression][8.0.1] TouchBevavior binding not working in a CollectionView #1804

Closed

2 tasks

TheCodeTraveler removed the needs discussion Discuss it on the next Monthly standup label May 2, 2024

github-actions Bot locked and limited conversation to collaborators Nov 20, 2024

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For All `CommunityToolkit.Maui.Behavior`s, Ensure `BindingContext` Is Automatically Set to the Attached View's `BindingContext`#1791

For All `CommunityToolkit.Maui.Behavior`s, Ensure `BindingContext` Is Automatically Set to the Attached View's `BindingContext`#1791
TheCodeTraveler merged 22 commits intomainfrom
Update-All-Behaviors-to-Inherit-from-`BaseBehavior`

TheCodeTraveler commented Apr 3, 2024 •

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Description of Change

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Axemasta commented Apr 3, 2024

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TheCodeTraveler commented Apr 3, 2024 •

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