To use the Angular forms, First, we need to import the FormsModule (for template-driven forms) & ReactiveFormsModule ( for Reactive Forms) from the in your route module. One is Template-driven and the other one is Reactive Forms. The Angular has two approaches to building the Angular Forms. It allows us to track changes made to the value in real-time and respond to it.
The observable gets the latest value of the control. It returns an observable so that you can subscribe to it. It tracks the value & validity of the entire form. The ValueChanges is an event raised by the Angular forms whenever the value of the FormControl, FormGroup or FormArray changes. Using FormGroupĮvery Angular Form must have at least one top-level FormGroup. For example, if one of the controls in a group is invalid, the entire group becomes invalid.
It calculates its status by reducing the status values of its children. A FormGroup aggregates the values of each child FormControl into one object, with each control name as the key. For Example form elements like address, city.state, pin code etc can be grouped together as a single FormGroup. We create a FormGroup to organize and manage the related elements. set its values & listen for change events, add and run validations on the group, etc We can use it to check the validity of the elements.
It Tracks the value and validation status of each of these control. The FormGroup solve’s this issue by providing a wrapper around a collection of FormControls It encapsulates all the information related to a group of form elements. It is cumbersome to loop over large no of FormControls and check for validity Imagine a form having a large no of fields. If we wanted to check the validity of our form, we have to check the validity of each and every FormControl for validity. All of the above input fields are represented as the separate FormControl. It tracks the value & validity of these elements. I'd like to have properly refreshed DOM when I toggle control's state using new instance of FormGroup.We create a FormControl for each of these input fields. I know, that I can use enable() and disable() methods, but in my case I'm generating complete FormGroups and I have to replace them.įor now I'm using workaround which crawls through whole AbstractControls tree and runs enable() and disable() methods but I believe it should be fixed in better way inside framework. I created second plunker with one small change, I'm binding controls using instead of formControlName and it behaves slightly different: it hasn't got any problems with switching state to disabled but it can't return to enabled state. Name input hasn't changed state to disabled.Īfter each step value and state are updated inside connected FormControl (printed values) but change of disabled/enabled state is not propagated to DOM. Click on 'Two disabled fields' button.
Title select hasn't changed state to enabled.
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