I have an angular Form and it used *ngFor for repeat an input box. Also, I have to validate dynamically all input boxes that are generated by *ngFor.
There is a JSON array called list that contains Questions. and I have to generate input boxes for answers and they should be validated. Validation information also in the list.
This is an example of the list
[{id:1,
mandatory:false,
questionDescription:"Blue flags are in position and contain words “Stop, Tank Car Connected” or “Stop, Men at Work”",
questionType:1,
validation:{maximum:100,minimum:0}},
{id:2,
mandatory:true,
questionDescription:"Wheels are chocked and handbrake(s) set” or “Stop, Men at Work",
questionType:2,
validation:{maxLength:10,minLength:3}}]
I tried to validate generated input boxes as described in here. https://scotch.io/tutorials/angular-2-form-validation (see validation forms there).
So I have to give validation information for each input boxes like below. (this example from given tutorial)
constructor(fb: FormBuilder){
this.complexForm = fb.group({
'firstName' : [null, Validators.required],
'lastName': [null, Validators.compose([Validators.required, Validators.minLength(5), Validators.maxLength(10)])]
})
this is the HTML for it.
<div class="form-group">
<label>First Name:</label>
<input class="form-control" type="text"[formControl]="complexForm.controls['firstName']">
</div>
<div class="form-group" >
<label>Last Name</label>
<input class="form-control" type="text" [formControl]="complexForm.controls['lastName']">
</div>
So in my case, all input boxes generate by *ngFor and I have to assign tags like firstName, lastName dynamically to those boxes.
So I used question.id as that tag and implemented control group as followed.
inspectionForm: FormGroup;
constructor(fb: FormBuilder) {
this.questionTemplate = templateService.getQuestionTemplate();
let objString: string = "{";
for (let item of this.questionTemplate.sectionList[0].questionList) {
if (item.questionType == 2) {
objString += '"' + item.id + '":null,';
}
}
objString = objString.slice(0, -1);
objString += '}';
let objJson = JSON.parse(objString);
for (let item of this.questionTemplate.sectionList[0].questionList) {
if (item.questionType == 2) {
objJson[item.id] = [null,Validators.compose([Validators.minLength(item.validation.minLength), Validators.maxLength(item.validation.maxLength)])];
}
}
this.inspectionForm = fb.group(objJson);
}
and here is my HTML code.
<form [formGroup]="inspectionForm" (ngSubmit)="submitForm(inspectionForm.value)">
<div *ngFor="let question of section.questionList" [ngSwitch]="question.questionType">
<ion-row *ngSwitchCase="QuestionType.String">
<ion-col width-80>{{question.questionDescription}}</ion-col>
<ion-col width-20>
<ion-input id="{{question.id}}" type="text" class="inspection-bottom-border" [formControl]="inspectionForm.controls['{{question.id}}']"></ion-input>
</ion-col>
</ion-row>
</div>
<div class="form-group">
<button type="submit" class="btn btn-primary" [disabled]="!inspectionForm.valid">Submit</button>
</div>
</form>
The Problem is....
If I define [formControl] as [formControl]="inspectionForm.controls['{{question.id}}']"
I get an error like follows,
unhandled Promise rejection: Template parse errors:
Parser Error: Got interpolation ({{}}) where expression was expected at column 25 in [inspectionForm.controls['{{question.id}}']] in InspectionPage@36:91 ("idth-20>
<ion-input id="{{question.id}}" type="text" class="inspection-bottom-border" [ERROR ->][formControl]="inspectionForm.controls['{{question.id}}']"></ion-input>
then I searched for an answer in StackOverflow, I found someone has said don't use [] and {{}} in one time (Dynamic routerLink value from ngFor item giving error "Got interpolation ({{}}) where expression was expected")
But if I removed [] and defined as follows
formControl="inspectionForm.controls['{{question.id}}']"
I get an error as follows
EXCEPTION: Error in ./InspectionPage class InspectionPage - inline template:36:91 caused by: Cannot create property 'validator' on string 'inspectionForm.controls['2']'
(this '2' the is question.id of first type 2 question)
if I define as follows same error occurs
formControl="inspectionForm.controls['2']"
But the problem is if I define as follows with [formControl]
[formControl]="inspectionForm.controls['2']"
The app is Working Perfectly....
But I have to give question.id dynamically. How I can do that?
Are there someone have a solution for this error. Please give a suggestion.
Thank you very much.
