I am making angular application with reactive form, where i have made a nested form array which will get nested on button click.
A clean working example https://stackblitz.com/edit/angular-thhczx , it has static inputs and hence on click over Add new template, it will add a another nested part and for Add new property, it will generate another property array..
So you had got the above working example concept right??
I would like to have the same json but not with add button and with dropdown.
Html of dropdown:
<select multiple [(ngModel)]="selectItems" (change)="changeEvent($event)">
<option *ngFor="let template of templates" [value]="template.key">{{template.value}}</option>
</select>
{{selectItems|json}}
<form [formGroup]="form">
<div *ngFor="let item of array">
{{item.value}} is the parent
<div *ngFor="let child of item.templateChild">
{{child.property_name}}
<input type="text" [value]="child.property_name">
</div>
<br><br><br>
</div>
</form>
<br><br><br>
{{form.value|json}}
but you want to do the things dinamically, so, make a function that receive an object and return a FormGroup. As you only need the "value" of the template and the childs, your function can be like
So yet we can create a formGroup for the differents templates and join in a FormArray
changeEvent(e) {
let arrayControls:FormGroup[] = [];
//in this.selectItems we have, e.g. [1,3]
for (let select of this.selectItems) {
//search the template, select will be e.g. 1,3
let template:any=this.templates.find(x=>x.key==select);
switch (+select) {
case 1:
arrayControls.push(this.createFormGroup(template.value,template.templateOneChild));
break;
case 2:
arrayControls.push(this.createFormGroup(template.value,template.templateTwoChild));
break;
case 3:
arrayControls.push(this.createFormGroup(template.value,template.templateThreeChild));
break;
}
}
this.form=this.fb.group({
template_details:this.fb.array(arrayControls);
})
}
See that if all ours children of templates was under a property "children" (not templateOneChild for the first, templateTwoChild for the seconds...) our function becomes in
changeEvent(e) {
let arrayControls:FormGroup[] = [];
//in this.selectItems we have, e.g. [1,3]
for (let select of this.selectItems) {
//search the template, select will be e.g. 1,3
let template:any=this.templates.find(x=>x.key==select);
arrayControls.push(this.createFormGroup(template.value,template.children));
}
this.form=this.fb.group({
template_details:this.array(arrayControls);
})
}
Well you have the "form" created, now is time to show it. The form is like
Yes, we have a problem, we don't know the "formControlName" of the inner formArray. One solution is have a variable "controlsName" that will be an array of array, so, if e.g. we choose 1 and 3 template our controlsName was like
Well, again make a function that return an array of strings with the names of the properties. it's a simply version of our createFormGroup, receive "children" and return an array of strings.
getControlNames(children:any[]):string[]
{
let controlNames:string[]=children.map(x=>x.property_name);
return controlNames;
}
Well, in changeEvent we call to this function after call to createFormGroup
changeEvent(e) {
let arrayControls:FormGroup[] = [];
let controlsName:string[] = []; //<--add this line
for (let select of this.selectItems) {
let template:any=this.templates.find(x=>x.key==select);
switch (+select) {
case 1:
arrayControls.push(this.createFormGroup(template.value,template.templateOneChild));
controlsName.push(this.getControlNames(template.templateOneChild)); //<--and this
break;
... idem with case 2 and case 3...
}
}
this.controlsName=controlsName; //<--give value to name first
//then create the form
this.form=this.fb.group({
template_details:this.fb.array(arrayControls);
})
After this, replace the < input formControlName="??????????" > by
<input [formControlName]="controlsName[i][j]">
See that we use [formControlName] (not formControlName) because is an evaluated expression.
