xamarin/Xamarin.Forms

Trigger Does Not Reset to Binding - Xamarin.Forms

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#5,422 opened on Mar 1, 2019

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a/binding ⛓e/2 :clock2:good first issuehelp wantedinactivet/bug :bug:up-for-grabs

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Description

Description

The issue occurs when the xaml element has a binding and a trigger. When the trigger resets 'back', the binding is lost.

Steps to Reproduce

  1. Open the sample app. I tested in Uwp.
  2. Change the color using the provided Picker. The BoxView changes to the selected color.
  3. Use the ‘Is Enabled’ switch to toggle the box to Disabled. This will cause the Trigger to fire.
  4. Use the ‘Is Enabled’ switch - the color reverts back to the original bound color.
  5. Select a new color in the picker.

Expected Behavior

The Color is still Bound to the selected Picker item.

Actual Behavior

The Color is stuck at the value it originally had, and will only respond to the Trigger, not the Binding.

Basic Information

  • Version with issue: 3.4.0.1008975 and 3.5.0.169047
  • Last known good version: Unknown
  • IDE: VS2017
  • Platform Target Frameworks:
    • UWP: 16299
  • Nuget Packages: None
  • Affected Devices: Windows 10, 1803

Screenshots

  1. The control is bound correctly... image
  2. The control responds to a the bound object changing... image
  3. The control responds to the trigger, which turns it yellow... image
  4. The control responds to the trigger resetting... image
  5. Bug - the control does not respond to the bound value image

Reproduction Link

https://github.com/jkastner/XamFormsBugSample_Triggers

Contributor guide

Research direction
Investigate how triggers interact with bindings in Xamarin.Forms, particularly the reset behavior after trigger removal. Check if the binding is being overridden and not restored when the trigger condition changes back.
Tech stack
csharp
Domain
mobile
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
csharp
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60