angular / angular/components

bug(autocomplete): DisplayWith retriggering + Programmatical value selection

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#28,161 1 comment 1 reaction 0 assignees View on GitHub
area: material/autocomplete P3
Dominant language
TypeScript
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Description

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

1. It's impossible to retrigger displayWith method (only when resetting form value).
2. Initial data is not displayed on dropdown with checkmark symbol, when property is binded. After selection all is working
2.1 When changing value programatically, checkmark is displayed on wrong selection.

### Reproduction

StackBlitz link: https://stackblitz.com/edit/zkwk2u
Steps to reproduce:
1. Change language
2. Value is not translated + not possible trigger displayWith. I tried different things, even updateValueAndValidity on formControl, which should really execute ValueChanges. Only when changing property value with setValue, it triggers displayWith method. With this approach I saw second problem, with programmatically changing control value.

1. Open link, selected value is displayed correctly with displayWith
2. Open dropdown no selection is displayed.
3. Select new value (first value) from dropdown (value is displayed correctly with check mark)
4. Click button (it changes value to 3, 3rd selection)
5. Value change is triggered and input shows correct data.
6. Open dropdown, it still shows wrong selection

### Expected Behavior

1. It's possible to trigger programmatically displayWith
2. Programmatically selected value + initial value is displayed correctly

### Actual Behavior

1. When already displayed value with displayWith, then this is not possible to change
2. Selection is not shown or shown wrongly

### Environment

- Angular: 17.0.0
- CDK/Material: 17.0.1
- Browser(s):
- Operating System (e.g. Windows, macOS, Ubuntu):

Contributor guide

Open the contributing guide

Research direction

Start with the linked StackBlitz reproduction and inspect the Angular Material autocomplete behavior around displayWith, initial values, and programmatic setValue changes. Done means displayWith can be retriggered programmatically and the dropdown checkmark tracks both the initial and programmatically selected values correctly.

Written by the indexing model from the issue text.

Assessment

Tech stack
angular, typescript
Domain
frontend
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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