updated Creating a Custom Form Field doc ngControl section #9855
Conversation
…lect errors injecting NgControl If the component already implements ControlValueAccessor, injecting NgControl in the constructor (as described in the docs) may fail. Added an alternate way.
rellis-of-rhindleton
requested review from
amcdnl and
jelbourn
as code owners
|
Thanks for your pull request. It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA). 📝 Please visit https://cla.developers.google.com/ to sign. Once you've signed, please reply here (e.g.
|
googlebot
added
the
cla: no
|
Signed CLA. |
|
CLAs look good, thanks! |
googlebot
added
cla: yes
| // ... | ||
|
|
||
| ngAfterViewInit() { | ||
| this.ngControl = this._injector.get(NgControl); |
There was a problem hiding this comment.
I don't think that this is the proper way to handle it either. Instead of providing the NG_VALUE_ACCESSOR, you can set the accessor the same way we do for mat-select. See https://github.com/angular/material2/blob/master/src/lib/select/select.ts#L489
There was a problem hiding this comment.
Ah, I saw two approaches and picked the other one. Not knowing enough about Angular internals it’s hard to say which is better. I’ll revise.
|
Revision added. |
There was a problem hiding this comment.
@rellis-of-rhindleton Awesome, thanks for this! one small wording request and then I'll mark it as ready to merge
| ``` | ||
|
|
||
| Note that if your component implements `ControlValueAccessor`, it may already be set up to provide `NG_VALUE_ACCESSOR` (in the `providers` part of the component's decorator, or possibly in a module declaration). If so you may get a *cannot instantiate cyclic dependency* error. | ||
|
|
||
| To resolve this, remove the `NG_VALUE_ACCESSOR` and instead set the value accessor directly: |
There was a problem hiding this comment.
...remove the NG_VALUE_ACCESSOR provider and...
|
Good call, done. |
* Creating a custom form field docs -- updated ngControl section to reflect errors injecting NgControl If the component already implements ControlValueAccessor, injecting NgControl in the constructor (as described in the docs) may fail. Added an alternate way. * Update creating-a-custom-form-field-control.md * added word "provider" for clarity
|
This issue has been automatically locked due to inactivity. Read more about our automatic conversation locking policy. This action has been performed automatically by a bot. |
If the component already implements ControlValueAccessor, injecting NgControl in the constructor (as described in the docs) may fail. Added an alternate approach to get past this problem.