angular/components

Radio-group's value not updated when the selected radio-button's value changes

Open

#9,808 opened on Feb 6, 2018

View on GitHub
 (2 comments) (0 reactions) (0 assignees)TypeScript (24,044 stars) (6,650 forks)batch import
P4area: material/radiohelp wanted

Description

Bug, feature request, or proposal:

Bug

What is the expected behavior?

value input of MatRadioButton to update ngModel of MatRadioGroup when selected.

What is the current behavior?

MatRadioGroup's value updates but not the ngModel.

What are the steps to reproduce?

https://stackblitz.com/edit/radio-binding?file=app%2Fapp.component.html

What is the use-case or motivation for changing an existing behavior?

Custom radio option with input

Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Angular and Material 5.0

Is there anything else we should know?

Calling radioGroup._controlValueAccessorChangeFn($event); on (ngModelChange) is a work around.

Contributor guide

Tech stack
angulartypescript
Domain
frontend
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.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Angular fundamentalsAngular MaterialTypeScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
Investigate the radio button and radio group component implementation, specifically how the value is propagated to ngModel. Look at the ` controlValueAccessorChangeFn` workaround and determine why it is needed. The fix likely involves ensuring the radio group's value change triggers the control value accessor change function properly. Consider adding a unit test for the scenario.