问题
In db table, I have "key_name" which is successfully returning in API and working great.
What I want to do is to set those fields value as a formControlName in html and in component I am using the reactive form so I have tried formArrayName.
Based on the change event I am pushing new formControl in categoryArray and assigning its key as db field's value.
here is my Html:
<div class="col-md-6">
<div formArrayName="categoryArray" *ngFor="let type of types; let k = index">
<div [formGroupName]="k">
<div class="form-group">
<label>Select {{ type.cat_name }}</label>
<select class="form-control custom-select"
(change)="onChangeType($event.target.value)"
formControlName="{{ type.key_name }}" >
<option value="">-- Select --</option>
<option *ngFor="let type of types" [value]="type.category_id">
{{type.cat_name}}
</option>
</select>
</div>
</div>
</div>
</div>
component.ts:
onChangeCategory(id) {
if(id) {
this.artistService.fetchTypeAndSubTypes(id).subscribe(res => {
if (res.status == 200) {
this.types = res.data
this.addInNewCategory(this.types)
}
})
} else {
this.types = null
this.subTypes = null
}
}
get category(): FormArray {
return <FormArray>this.uploadArtWorkForm.controls.categoryArray;
}
addInNewCategory(types) {
let obj = {}
types.forEach(element => {
obj[element['key_name']] = [null, [Validators.required]]
});
console.log("obj", obj)
this.category.push(
this.formBuilder.group(obj)
);
}
What I want to archive is that based on 1st category selection all 2nd level category will be shown as a dynamic HTML dropdown who has their child category listing in the dropdown.
Errors that I am getting:
ERROR Error: Cannot find control with path: 'categoryArray -> 1'
ERROR Error: Cannot find control with path: 'categoryArray -> 1 -> metal'
EDIT: After setting up form control name, How can I set each newly created dropdown's value ? I need to fetch it from the db.
Here is Stackblitz: https://stackblitz.com/edit/dyncamic-populating-dropdown
Thanks in advance
回答1:
Tried modifying your code myself at least the errors below are fixed:
ERROR Error: Cannot find control with path: 'categoryArray -> 1'
ERROR Error: Cannot find control with path: 'categoryArray -> 1 -> metal'
But you still need to improve on your end using my solution.
Modify your app.component.html as below:
<form [formGroup]="uploadArtWorkForm" (ngSubmit)="addUploadArtWorkForm();">
<div class="col-md-6">
<div class="form-group">
<label>Select Category:</label>
<select class="form-control custom-select" formControlName="cat_id" [ngClass]="{'is-invalid': uploadArtWorkForm.controls['cat_id'].invalid && (uploadArtWorkForm.controls['cat_id'].dirty || uploadArtWorkForm.controls['cat_id'].touched || isFormSubmitted) }" (change)="onChangeCategory($event, $event.target.value)">
<option value="">-- Select --</option>
<option *ngFor="let category of parentCategories" [value] ="category.category_id">
{{category.cat_name}}
</option>
</select>
<div class="invalid-feedback" *ngIf="uploadArtWorkForm.controls['cat_id'].errors">
<div *ngIf="uploadArtWorkForm.controls['cat_id'].errors.required">Category is
required.</div>
</div>
</div>
</div>
<div class="col-md-6" formArrayName="categoryArray" *ngIf="uploadArtWorkForm.get('categoryArray')['controls'].length > 0">
<div *ngFor="let item of uploadArtWorkForm.get('categoryArray')['controls']; let k = index">
<div [formGroup]="item">
<div class="form-group ">
<label>Select {{ types[k].cat_name }}</label>
<select class="form-control custom-select" [class]="types[k].key_name" (change)="onChangeType($event.target.value)" formControlName="{{ types[k].key_name }}" *ngIf="types[k].cat_name == 'Type'">
<option value="">-- Select --</option>
<option *ngFor="let type of catTypeValue" [value]="type.category_id">
{{type.cat_name}}
</option>
</select>
<select class="form-control custom-select" [class]="types[k].key_name" (change)="onChangeType($event.target.value)" formControlName="{{ types[k].key_name }}" *ngIf="types[k].cat_name == 'Metal'">
<option value="">-- Select --</option>
<option *ngFor="let type of catMetalValue" [value]="type.category_id">
{{type.cat_name}}
</option>
</select>
<select class="form-control custom-select" [class]="types[k].key_name" (change)="onChangeType($event.target.value)" formControlName="{{ types[k].key_name }}" *ngIf="types[k].cat_name == 'Gems'">
<option value="">-- Select --</option>
<option *ngFor="let type of catGemsValue" [value]="type.category_id">
{{type.cat_name}}
</option>
</select>
</div>
</div>
</div>
</div>
</form>
and app.component.ts as below:
import { Component } from "@angular/core";
import { FormGroup, FormBuilder, Validators, FormArray, FormControl } from "@angular/forms";
@Component({
selector: "my-app",
templateUrl: "./app.component.html",
styleUrls: ["./app.component.css"]
})
export class AppComponent {
uploadArtWorkForm: any;
uploadArtWorkForm1: any;
isFormSubmitted: boolean = false;
parentCategories = [
{"parent_id":0,"cat_name":"Jewelry","category_id":1},
{"parent_id":0,"cat_name":"Painting","category_id":16},
{"parent_id":0,"cat_name":"Photograph","category_id":22}];
types;
subTypes;
//below value will be displayed in Select Type dropdown
catTypeValue = [
{"parent_id":2,"cat_name":"Anklets","category_id":3,"key_name":"anklets"},
{"parent_id":2,
"cat_name":"Body",
"category_id":4,
"key_name":"body"},
{"parent_id":2,"cat_name":"Bracelets","category_id":5,
"key_name":""},
{"parent_id":2,
"cat_name":"Charms","category_id":6,
"key_name":""},
{"parent_id":2,"cat_name":"Necklaces","category_id":7,
"key_name":""},
{"parent_id":2,"cat_name":"Ornamental","category_id":8,
"key_name":""},
{"parent_id":2,
"cat_name":"Rings & Studs","category_id":9,
"key_name":""},
{"parent_id":2,
"cat_name":"Jewelry Metal","category_id":10,"key_name":""},{"parent_id":2,
"cat_name":"Yellow Gold","category_id":11,
"key_name":""},
{"parent_id":2,
"cat_name":"White Gold","category_id":12,"key_name":"whitegold"},{"parent_id":2,
"cat_name":"Silver","category_id":13,"key_name":"silver"}
]
// below values will be displayed in Select Metal dd
catMetalValue = [
{"parent_id":14,"cat_name":"White Gold","category_id":24,"key_name":"whitegold"},
{"parent_id":14,"cat_name":"Yellow Gold","category_id":24,"key_name":"whitegold"},
]
// below values will be displayed in Select Gems dd
catGemsValue = [
{"parent_id":15,"cat_name":"Blue Gems","category_id":25,"key_name":"bluegems"}
]
constructor(private formBuilder: FormBuilder) {
this.uploadArtWorkForm = this.formBuilder.group({
cat_id: new FormControl('', Validators.required),
categoryArray: this.formBuilder.array([]),
});
}
ngOnInit() {}
onChangeType(value, id){
console.log(value)
// solution to https://stackoverflow.com/questions/61315779/angular-8-not-getting-selected-dropdown-values-in-component-using-reactive-form?noredirect=1&lq=1
}
onChangeCategory(event, id) {
if (id) {
this.types = [
{"parent_id":1,
"cat_name":"Type",
"category_id":2,
"key_name":"type"},
{"parent_id":1,
"cat_name":"Metal",
"category_id":14,
"key_name":"metal"},
{"parent_id":1,
"cat_name":"Gems",
"category_id":15,
"key_name":"gems"}];
if(this.uploadArtWorkForm.controls['categoryArray'].length > 0){
this.uploadArtWorkForm.controls['categoryArray'].controls.length = 0
}
this.addInNewCategory(this.types);
} else {
this.types = null;
this.subTypes = null;
}
}
get category(): FormArray {
return <FormArray>this.uploadArtWorkForm.controls['categoryArray'];
}
addInNewCategory(types) {['categoryArray'];
types.forEach((element, i) => {
this.category.push(this.formBuilder.group({[element["key_name"]]: new FormControl(element["key_name"])
}));
});
}
}
回答2:
Try Below,
Suppose you are getting from keys in formKeys Object
let formObj={};
Object.keys(this.formKeys||[]).forEach(d=>{
formObj[k]=["",Validators.required];
});
this.dynamicForm=this.fb.group(formObj);
In html:
<form [formGroup]="dynamicForm">
<div *ngFor="let key of ArrayOfFormKey">
<input [fromControlName]="key">
</div>
</form>
来源：https://stackoverflow.com/questions/61264403/angular-8-dynamically-set-formcontrolname-in-html-based-on-component