I have a reactive form with 4 inputs type radio and 4 inputs type text.
I want to display dynamically inputs text following the radio buttons
selected. For example, if button radio 1 selected, i want to display
its corresponding input text 1.
I encounter 2 problems :
The first radio button is not selected by default (even with attribute checked) and all the radio buttons can be selected at the same time.
All the inputs text are displayed, i don't know with a *ngIf how to
check if the radio button corresponding to the input is selected.
component.html :
<section class="CreateItem" *ngIf="formGroupItemSelection">
<form (ngSubmit)="addItem()" [formGroup]="formGroupItemSelection">
<input formControlName="refNumber" type="radio" value="refNumber" checked> ref number
<br>
<input formControlName="partNumber" type="radio" value="partNumber"> part number
<br>
<input formControlName="itemName" type="radio" value="itemName"> item name
<br>
<input formControlName="manufacturerName" type="radio" value="manufacturerName">manufacturer name
<br>
<div *ngIf="formGroupItemSelection.controls.refNumber.valid">
<input list="refNumbers" formControlName="refNumberSelected" type="text" name="refNumberSelected">
<datalist id="refNumbers">
<option *ngFor="let ref of listOfItems">{{ref.refNumber.input}}</option>
</datalist>
</div>
<div *ngIf="formGroupItemSelection.controls.partNumber.valid">
<input list="partNumbers" formControlName="partNumberSelected" type="text" name="partNumberSelected">
<datalist id="partNumbers">
<option *ngFor="let ref of listOfItems">{{ref.partNumber.input}}</option>
</datalist>
</div>
<div *ngIf="formGroupItemSelection.controls.itemName.valid">
<input list="itemsName" formControlName="itemNameSelected" type="text" name="itemNameSelected">
<datalist id="itemsName">
<option *ngFor="let ref of listOfItems">{{ref.itemDesignation.input}}</option>
</datalist>
</div>
<div *ngIf="formGroupItemSelection.controls.manufacturerName.valid">
<input list="manufacturersName" formControlName="manufacturerNameSelected" type="text" name="manufacturerNameSelected">
<datalist id="manufacturersName">
<option *ngFor="let ref of listOfItems">{{ref.manufacturerName.input}}</option>
</datalist>
</div>
<button type="submit [disabled]="!formGroupItemSelection.valid">Valider</button>
</form>
</section>
component.ts :
import { Component, OnInit } from '#angular/core';
import {FormControl, FormGroup, FormBuilder, Validators} from '#angular/forms'
import { ManagementArbologistiqueService } from '../../management-arbologistique.service';
import { ActivatedRoute, Params } from '#angular/router';
import { matchValuesRefNumber, matchValuesPartNumber, matchValuesItemName, matchValuesManufacturerName } from '../Validators/validators';
#Component({
selector: 'app-item-selection',
templateUrl: './item-selection.component.html',
styleUrls: ['./item-selection.component.css']
})
export class ItemSelectionComponent implements OnInit {
formGroupItemSelection:FormGroup;
listOfItems = [];
constructor(public fb:FormBuilder,private managementArbo: ManagementArbologistiqueService, private route: ActivatedRoute) { }
ngOnInit() {
this.getListBdd();
}
initializeForm() {
this.formGroupItemSelection = this.fb.group({
refNumber : '',
partNumber: '',
itemName: '',
manufacturerName: '',
refNumberSelected:[
null,
Validators.compose([Validators.required, matchValuesRefNumber(this.listOfItems)])
],
partNumberSelected:[
null,
Validators.compose([Validators.required, matchValuesPartNumber(this.listOfItems)])
],
itemNameSelected: [
null,
Validators.compose([Validators.required, matchValuesItemName(this.listOfItems)])
],
manufacturerNameSelected:[
null,
Validators.compose([Validators.required, matchValuesManufacturerName(this.listOfItems)])
]
})
}
getListBdd() {
this.route.params.subscribe((params: Params) => {
let subroute = "getRefNumber";
this.managementArbo.getProducts(subroute)
.subscribe(
res => {
this.listOfItems = res; console.log('bdd:' + res);
this.initializeForm();
},
err => console.log(err),
() => console.log('getProducts done'));
});
}
addItem() {
}
1.-NOT use "checked". just when you create the form give the correct value. And the correct value is not "true"
this.formGroupItemSelection = this.fb.group({
refNumber : ['refNumber'], //NOT is true or false
partNumber: [],
itemName: []
....
})
2.-When we make a *ngIf into a reactive form use myform.get('mycontrol'), e.g.
<div *ngIf="formGroupItemSelection.get('partNumber').valid">...</div>
I solved my problem !
Firstly, I found important information in the angular doc to answer my first question :
"To use radio buttons in a template-driven form, you'll want to ensure that radio buttons in the same group have the same name attribute. Radio buttons with different name attributes do not affect each other.".
Then, in the case of a reactive form :
"When using radio buttons in a reactive form, radio buttons in the same group should have the same formControlName. You can also add a name attribute, but it's optional."
So, i gave the same formControlName at each radio button and the mention "checked" works now.
Otherwise, to answer my second question, I identified each radio buttons following the "value" property of input, and checked if radio buttons selected :
<div *ngIf="formGroupItemSelection.controls.radioBoutton.value==='refNumber'">
Hope it can help !
initializeForm() {
this.formGroupItemSelection = this.fb.group({
refNumber : new FormControl(true),
partNumber: new FormControl(false),
itemName: new FormControl(false),
manufacturerName: '',
refNumberSelected:[
null,
Validators.compose([Validators.required, matchValuesRefNumber(this.listOfItems)])
],
partNumberSelected:[
null,
Validators.compose([Validators.required, matchValuesPartNumber(this.listOfItems)])
],
itemNameSelected: [
null,
Validators.compose([Validators.required, matchValuesItemName(this.listOfItems)])
],
manufacturerNameSelected:[
null,
Validators.compose([Validators.required, matchValuesManufacturerName(this.listOfItems)])
]
})
//This will set the radio button checked no need to add checked attribute you can set cheked dynamically
this.formGroupItemSelection.get('refNumber ').setValue(true);
this.formGroupItemSelection.get('partNumber').setValue(true);
this.formGroupItemSelection.get('itemName').setValue(true)
}
Given a list of checkboxes bound to the same formControlName, how can I produce an array of checkbox values bound to the formControl, rather than simply true/false?
Example:
<form [formGroup]="checkboxGroup">
<input type="checkbox" id="checkbox-1" value="value-1" formControlName="myValues" />
<input type="checkbox" id="checkbox-2" value="value-2" formControlName="myValues" />
<input type="checkbox" id="checkbox-3" value="value-2" formControlName="myValues" />
</form>
checkboxGroup.controls['myValues'].value currently produces:
true or false
What I want it to produce:
['value-1', 'value-2', ...]
With the help of silentsod answer, I wrote a solution to get values instead of states in my formBuilder.
I use a method to add or remove values in the formArray. It may be a bad approch, but it works !
component.html
<div *ngFor="let choice of checks; let i=index" class="col-md-2">
<label>
<input type="checkbox" [value]="choice.value" (change)="onCheckChange($event)">
{{choice.description}}
</label>
</div>
component.ts
// For example, an array of choices
public checks: Array<ChoiceClass> = [
{description: 'descr1', value: 'value1'},
{description: "descr2", value: 'value2'},
{description: "descr3", value: 'value3'}
];
initModelForm(): FormGroup{
return this._fb.group({
otherControls: [''],
// The formArray, empty
myChoices: new FormArray([]),
}
}
onCheckChange(event) {
const formArray: FormArray = this.myForm.get('myChoices') as FormArray;
/* Selected */
if(event.target.checked){
// Add a new control in the arrayForm
formArray.push(new FormControl(event.target.value));
}
/* unselected */
else{
// find the unselected element
let i: number = 0;
formArray.controls.forEach((ctrl: FormControl) => {
if(ctrl.value == event.target.value) {
// Remove the unselected element from the arrayForm
formArray.removeAt(i);
return;
}
i++;
});
}
}
When I submit my form, for example my model looks like:
otherControls : "foo",
myChoices : ['value1', 'value2']
Only one thing is missing, a function to fill the formArray if your model already has checked values.
Here's a good place to use the FormArray https://angular.io/docs/ts/latest/api/forms/index/FormArray-class.html
To start we'll build up our array of controls either with a FormBuilder or newing up a FormArray
FormBuilder
this.checkboxGroup = _fb.group({
myValues: _fb.array([true, false, true])
});
new FormArray
let checkboxArray = new FormArray([
new FormControl(true),
new FormControl(false),
new FormControl(true)]);
this.checkboxGroup = _fb.group({
myValues: checkboxArray
});
Easy enough to do, but then we're going to change our template and let the templating engine handle how we bind to our controls:
template.html
<form [formGroup]="checkboxGroup">
<input *ngFor="let control of checkboxGroup.controls['myValues'].controls"
type="checkbox" id="checkbox-1" value="value-1" [formControl]="control" />
</form>
Here we're iterating over our set of FormControls in our myValues FormArray and for each control we're binding [formControl] to that control instead of to the FormArray control and <div>{{checkboxGroup.controls['myValues'].value}}</div> produces true,false,true while also making your template syntax a little less manual.
You can use this example: http://plnkr.co/edit/a9OdMAq2YIwQFo7gixbj?p=preview to poke around
It's significantly easier to do this in Angular 6 than it was in previous versions, even when the checkbox information is populated asynchronously from an API.
The first thing to realise is that thanks to Angular 6's keyvalue pipe we don't need to have to use FormArray anymore, and can instead nest a FormGroup.
First, pass FormBuilder into the constructor
constructor(
private _formBuilder: FormBuilder,
) { }
Then initialise our form.
ngOnInit() {
this.form = this._formBuilder.group({
'checkboxes': this._formBuilder.group({}),
});
}
When our checkbox options data is available, iterate it and we can push it directly into the nested FormGroup as a named FormControl, without having to rely on number indexed lookup arrays.
const checkboxes = <FormGroup>this.form.get('checkboxes');
options.forEach((option: any) => {
checkboxes.addControl(option.title, new FormControl(true));
});
Finally, in the template we just need to iterate the keyvalue of the checkboxes: no additional let index = i, and the checkboxes will automatically be in alphabetical order: much cleaner.
<form [formGroup]="form">
<h3>Options</h3>
<div formGroupName="checkboxes">
<ul>
<li *ngFor="let item of form.get('checkboxes').value | keyvalue">
<label>
<input type="checkbox" [formControlName]="item.key" [value]="item.value" /> {{ item.key }}
</label>
</li>
</ul>
</div>
</form>
I don't see a solution here that completely answers the question using reactive forms to its fullest extent so here's my solution for the same.
Summary
Here's the pith of the detailed explanation along with a StackBlitz example.
Use FormArray for the checkboxes and initialize the form.
The valueChanges observable is perfect for when you want the form to display something but store something else in the component. Map the true/false values to the desired values here.
Filter out the false values at the time of submission.
Unsubscribe from valueChanges observable.
StackBlitz example
Detailed explanation
Use FormArray to define the form
As already mentioned in the answer marked as correct. FormArray is the way to go in such cases where you would prefer to get the data in an array. So the first thing you need to do is create the form.
checkboxGroup: FormGroup;
checkboxes = [{
name: 'Value 1',
value: 'value-1'
}, {
name: 'Value 2',
value: 'value-2'
}];
this.checkboxGroup = this.fb.group({
checkboxes: this.fb.array(this.checkboxes.map(x => false))
});
This will just set the initial value of all the checkboxes to false.
Next, we need to register these form variables in the template and iterate over the checkboxes array (NOT the FormArray but the checkbox data) to display them in the template.
<form [formGroup]="checkboxGroup">
<ng-container *ngFor="let checkbox of checkboxes; let i = index" formArrayName="checkboxes">
<input type="checkbox" [formControlName]="i" />{{checkbox.name}}
</ng-container>
</form>
Make use of the valueChanges observable
Here's the part I don't see mentioned in any answer given here. In situations such as this, where we would like to display said data but store it as something else, the valueChanges observable is very helpful. Using valueChanges, we can observe the changes in the checkboxes and then map the true/false values received from the FormArray to the desired data. Note that this will not change the selection of the checkboxes as any truthy value passed to the checkbox will mark it as checked and vice-versa.
subscription: Subscription;
const checkboxControl = (this.checkboxGroup.controls.checkboxes as FormArray);
this.subscription = checkboxControl.valueChanges.subscribe(checkbox => {
checkboxControl.setValue(
checkboxControl.value.map((value, i) => value ? this.checkboxes[i].value : false),
{ emitEvent: false }
);
});
This basically maps the FormArray values to the original checkboxes array and returns the value in case the checkbox is marked as true, else it returns false. The emitEvent: false is important here since setting the FormArray value without it will cause valueChanges to emit an event creating an endless loop. By setting emitEvent to false, we are making sure the valueChanges observable does not emit when we set the value here.
Filter out the false values
We cannot directly filter the false values in the FormArray because doing so will mess up the template since they are bound to the checkboxes. So the best possible solution is to filter out the false values during submission. Use the spread operator to do this.
submit() {
const checkboxControl = (this.checkboxGroup.controls.checkboxes as FormArray);
const formValue = {
...this.checkboxGroup.value,
checkboxes: checkboxControl.value.filter(value => !!value)
}
// Submit formValue here instead of this.checkboxGroup.value as it contains the filtered data
}
This basically filters out the falsy values from the checkboxes.
Unsubscribe from valueChanges
Lastly, don't forget to unsubscribe from valueChanges
ngOnDestroy() {
this.subscription.unsubscribe();
}
Note: There is a special case where a value cannot be set to the FormArray in valueChanges, i.e if the checkbox value is set to the number 0. This will make it look like the checkbox cannot be selected since selecting the checkbox will set the FormControl as the number 0 (a falsy value) and hence keep it unchecked. It would be preferred not to use the number 0 as a value but if it is required, you have to conditionally set 0 to some truthy value, say string '0' or just plain true and then on submitting, convert it back to the number 0.
StackBlitz example
The StackBlitz also has code for when you want to pass default values to the checkboxes so they get marked as checked in the UI.
TL;DR
I prefer to use FormGroup to populate the list of checkbox
Write a custom validator to check at least one checkbox was selected
Working example https://stackblitz.com/edit/angular-validate-at-least-one-checkbox-was-selected
This also struck me sometimes so I did try both FormArray and FormGroup approaches.
Most of the time, the list of checkboxes was populated on the server and I received it through API. But sometimes you will have a static set of checkboxes with your predefined value. With each use case, the corresponding FormArray or FormGroup will be used.
Basically FormArray is a variant of FormGroup. The key difference is that its data gets serialized as an array (as opposed to being serialized as an object in case of FormGroup). This might be especially useful when you don’t know how many controls will be present within the group, like dynamic forms.
For the sake of simplicity, imagine you have a simple create product form with
One required product name textbox.
A list of categories to select from, required at least one to be checked. Assume the list will be retrieved from the server.
First, I set up a form with only the product name formControl. It is a required field.
this.form = this.formBuilder.group({
name: ["", Validators.required]
});
Since the category is dynamically rendering, I will have to add these data into the form later after the data was ready.
this.getCategories().subscribe(categories => {
this.form.addControl("categoriesFormArr", this.buildCategoryFormArr(categories));
this.form.addControl("categoriesFormGroup", this.buildCategoryFormGroup(categories));
})
There are two approaches to build up the category list.
1. Form Array
buildCategoryFormArr(categories: ProductCategory[], selectedCategoryIds: string[] = []): FormArray {
const controlArr = categories.map(category => {
let isSelected = selectedCategoryIds.some(id => id === category.id);
return this.formBuilder.control(isSelected);
})
return this.formBuilder.array(controlArr, atLeastOneCheckboxCheckedValidator())
}
<div *ngFor="let control of categoriesFormArr?.controls; let i = index" class="checkbox">
<label><input type="checkbox" [formControl]="control" />
{{ categories[i]?.title }}
</label>
</div>
This buildCategoryFormGroup will return me a FormArray. It also takes a list of selected values as an argument so If you want to reuse the form for editing data, it could be helpful. For the purpose of creating a new product form, it is not applicable yet.
Noted that when you try to access the formArray values. It will looks like [false, true, true]. To get a list of selected id, it required a bit more work to check from the list but based on the array index. Doesn't sound good to me but it works.
get categoriesFormArraySelectedIds(): string[] {
return this.categories
.filter((cat, catIdx) => this.categoriesFormArr.controls.some((control, controlIdx) => catIdx === controlIdx && control.value))
.map(cat => cat.id);
}
That's why I came up using FormGroup for that matter
2. Form Group
formGroup will store the form data as the object, which required a key map to a form control. So it is a good idea to set the key as the categoryId and then we can retrieve it later.
buildCategoryFormGroup(categories: ProductCategory[], selectedCategoryIds: string[] = []): FormGroup {
let group = this.formBuilder.group({}, {
validators: atLeastOneCheckboxCheckedValidator()
});
categories.forEach(category => {
let isSelected = selectedCategoryIds.some(id => id === category.id);
group.addControl(category.id, this.formBuilder.control(isSelected));
})
return group;
}
<div *ngFor="let item of categories; let i = index" class="checkbox">
<label><input type="checkbox" [formControl]="categoriesFormGroup?.controls[item.id]" /> {{ categories[i]?.title }}
</label>
</div>
The value of the form group will look like this:
{
"category1": false,
"category2": true,
"category3": true,
}
But most often we want to get only the list of categoryIds as ["category2", "category3"]. I also have to write a get to take these data. I like this approach better compared to the formArray, because I could actually take the value from the form itself.
get categoriesFormGroupSelectedIds(): string[] {
let ids: string[] = [];
for (var key in this.categoriesFormGroup.controls) {
if (this.categoriesFormGroup.controls[key].value) {
ids.push(key);
}
else {
ids = ids.filter(id => id !== key);
}
}
return ids;
}
3. Custom validator to check at least one checkbox was selected
I made the validator check at least X checkbox was selected, by default it will check against one checkbox only.
export function atLeastOneCheckboxCheckedValidator(minRequired = 1): ValidatorFn {
return function validate(formGroup: FormGroup) {
let checked = 0;
Object.keys(formGroup.controls).forEach(key => {
const control = formGroup.controls[key];
if (control.value) {
checked++;
}
});
if (checked < minRequired) {
return {
requireCheckboxToBeChecked: true,
};
}
return null;
};
}
If you are looking for checkbox values in JSON format
{ "name": "", "countries": [ { "US": true }, { "Germany": true }, { "France": true } ] }
Full example here.
I apologise for using Country Names as checkbox values instead of those in the question. Further explannation -
Create a FormGroup for the form
createForm() {
//Form Group for a Hero Form
this.heroForm = this.fb.group({
name: '',
countries: this.fb.array([])
});
let countries=['US','Germany','France'];
this.setCountries(countries);}
}
Let each checkbox be a FormGroup built from an object whose only property is the checkbox's value.
setCountries(countries:string[]) {
//One Form Group for one country
const countriesFGs = countries.map(country =>{
let obj={};obj[country]=true;
return this.fb.group(obj)
});
const countryFormArray = this.fb.array(countriesFGs);
this.heroForm.setControl('countries', countryFormArray);
}
The array of FormGroups for the checkboxes is used to set the control for the 'countries' in the parent Form.
get countries(): FormArray {
return this.heroForm.get('countries') as FormArray;
};
In the template, use a pipe to get the name for the checkbox control
<div formArrayName="countries" class="well well-lg">
<div *ngFor="let country of countries.controls; let i=index" [formGroupName]="i" >
<div *ngFor="let key of country.controls | mapToKeys" >
<input type="checkbox" formControlName="{{key.key}}">{{key.key}}
</div>
</div>
</div>
If you want to use an Angular reactive form (https://angular.io/guide/reactive-forms).
You can use one form control to manage the outputted value of the group of checkboxes.
component
import { Component } from '#angular/core';
import { FormGroup, FormControl } from '#angular/forms';
import { flow } from 'lodash';
import { flatMap, filter } from 'lodash/fp';
#Component({
selector: 'multi-checkbox',
templateUrl: './multi-checkbox.layout.html',
})
export class MultiChecboxComponent {
checklistState = [
{
label: 'Frodo Baggins',
value: 'frodo_baggins',
checked: false
},
{
label: 'Samwise Gamgee',
value: 'samwise_gamgee',
checked: true,
},
{
label: 'Merry Brandybuck',
value: 'merry_brandybuck',
checked: false
}
];
form = new FormGroup({
checklist : new FormControl(this.flattenValues(this.checklistState)),
});
checklist = this.form.get('checklist');
onChecklistChange(checked, checkbox) {
checkbox.checked = checked;
this.checklist.setValue(this.flattenValues(this.checklistState));
}
flattenValues(checkboxes) {
const flattenedValues = flow([
filter(checkbox => checkbox.checked),
flatMap(checkbox => checkbox.value )
])(checkboxes)
return flattenedValues.join(',');
}
}
html
<form [formGroup]="form">
<label *ngFor="let checkbox of checklistState" class="checkbox-control">
<input type="checkbox" (change)="onChecklistChange($event.target.checked, checkbox)" [checked]="checkbox.checked" [value]="checkbox.value" /> {{ checkbox.label }}
</label>
</form>
checklistState
Manages the model/state of the checklist inputs. This model allows you to map the current state to whatever value format you need.
Model:
{
label: 'Value 1',
value: 'value_1',
checked: false
},
{
label: 'Samwise Gamgee',
value: 'samwise_gamgee',
checked: true,
},
{
label: 'Merry Brandybuck',
value: 'merry_brandybuck',
checked: false
}
checklist Form Control
This control stores the value would like to save as e.g
value output: "value_1,value_2"
See demo at https://stackblitz.com/edit/angular-multi-checklist
Make an event when it's clicked and then manually change the value of true to the name of what the check box represents, then the name or true will evaluate the same and you can get all the values instead of a list of true/false. Ex:
component.html
<form [formGroup]="customForm" (ngSubmit)="onSubmit()">
<div class="form-group" *ngFor="let parameter of parameters"> <!--I iterate here to list all my checkboxes -->
<label class="control-label" for="{{parameter.Title}}"> {{parameter.Title}} </label>
<div class="checkbox">
<input
type="checkbox"
id="{{parameter.Title}}"
formControlName="{{parameter.Title}}"
(change)="onCheckboxChange($event)"
> <!-- ^^THIS^^ is the important part -->
</div>
</div>
</form>
component.ts
onCheckboxChange(event) {
//We want to get back what the name of the checkbox represents, so I'm intercepting the event and
//manually changing the value from true to the name of what is being checked.
//check if the value is true first, if it is then change it to the name of the value
//this way when it's set to false it will skip over this and make it false, thus unchecking
//the box
if(this.customForm.get(event.target.id).value) {
this.customForm.patchValue({[event.target.id] : event.target.id}); //make sure to have the square brackets
}
}
This catches the event after it was already changed to true or false by Angular Forms, if it's true I change the name to the name of what the checkbox represents, which if needed will also evaluate to true if it's being checked for true/false as well.
Apparently, this is a very common problem and no one has a "perfect" solution. I believe I was able to come with a pretty elegant solution, using object orientation to extend the capabilities of FormGroup.
Desired API
In a single object I want to be able to have:
The form control for each checkbox
The label and value for each checkbox
The values of all selected checkbox
So the HTML structure can be simple as this:
<div *ngFor="let item of checkboxGroup.items">
<input type="checkbox" [id]="item.value" [formControl]="item.control">
<label [for]="item.value">{{ item.label }}</label>
</div>
And the typescript part can be simple as this:
checkboxGroup.value; // return the list of selected item values
checkboxGroup.control.valid; // return if there's at least one checked value
Solution
As you can see in the HTML part, the checkboxGroup needs to be a class with at least three properties:
items (each item is a checkbox with a value, label and a FormControl)
value (gets all selected items)
control (gets the FormArray control)
So the class will be like:
// # This represents a single checkbox item
class CheckboxItemControl {
label: string; // value to be shown in the UI
value: string; // value to be saved in backend
control: FormControl;
constructor({ label, value, defaultValue = false }: { label: string; value: string; defaultValue?: boolean }) {
this.label = label;
this.value = value;
this.control = new FormControl(defaultValue || false);
}
get selected(): boolean {
return Boolean(this.control.value);
}
}
// # This represents a checkbox group, with several items
class CheckboxGroupControl {
name?: string; // name of the checkbox group
items: CheckboxItemControl[];
control: FormArray;
constructor(name: string, items: CheckboxItemControl[]) {
this.name = name;
this.items = items;
this.control = new FormArray(this.getAllItemsControls(), CheckboxGroupControl.emptyArrayFormValidator);
}
get value(): string[] {
return this.selectedItems.map(item => item.value);
}
private get selectedItems(): CheckboxItemControl[] {
return this.items.filter(item => item.selected);
}
private getAllItemsControls(): FormControl[] {
return this.items.map(item => item.control);
}
private static emptyArrayFormValidator(control: FormControl) {
const valid = (control.value as boolean[]).some(Boolean);
// #todo improve error message
return valid ? null : {
error: 'empty'
};
}
}
You can see how each class exposes a simple API (object.value and object.control) which allows you to easily get all that you need.
Usage
So let's see in practice how it'll work:
HTML
<div *ngFor="let item of checkboxGroup.items">
<input type="checkbox" [id]="item.value" [formControl]="item.control">
<label [for]="item.value">{{ item.label }}</label>
</div>
Typescript
checkboxGroup;
ngOnInit() {
this.createFormInputs();
}
private createFormInputs() {
const checkboxItems = [
new CheckboxItemControl({ value: 'checkbox-1', label: 'Checkbox 1' }),
new CheckboxItemControl({ value: 'checkbox-2', label: 'Checkbox 2' }),
new CheckboxItemControl({ value: 'checkbox-3', label: 'Checkbox 3', defaultValue: true })
];
this.checkboxGroup = new CheckboxGroupControl('name_of_group', checkboxItems);
this.form = new FormGroup({
checkbox: this.checkboxGroup.control
});
// this.checkboxGroup.value returns ['checkbox-1', ...] for the selected checkboxes
// this.checkboxGroup.valid returns if there's any checkbox selected
// this.form.valid returns if the whole form is valid. Which is useful if you include others checkbox groups
}
Other resources
This article sparks the light for me to come up with this solution.
My solution - solved it for Angular 5 with Material View
The connection is through the
formArrayName="notification"
(change)="updateChkbxArray(n.id, $event.checked, 'notification')"
This way it can work for multiple checkboxes arrays in one form.
Just set the name of the controls array to connect each time.
constructor(
private fb: FormBuilder,
private http: Http,
private codeTableService: CodeTablesService) {
this.codeTableService.getnotifications().subscribe(response => {
this.notifications = response;
})
...
}
createForm() {
this.form = this.fb.group({
notification: this.fb.array([])...
});
}
ngOnInit() {
this.createForm();
}
updateChkbxArray(id, isChecked, key) {
const chkArray = < FormArray > this.form.get(key);
if (isChecked) {
chkArray.push(new FormControl(id));
} else {
let idx = chkArray.controls.findIndex(x => x.value == id);
chkArray.removeAt(idx);
}
}
<div class="col-md-12">
<section class="checkbox-section text-center" *ngIf="notifications && notifications.length > 0">
<label class="example-margin">Notifications to send:</label>
<p *ngFor="let n of notifications; let i = index" formArrayName="notification">
<mat-checkbox class="checkbox-margin" (change)="updateChkbxArray(n.id, $event.checked, 'notification')" value="n.id">{{n.description}}</mat-checkbox>
</p>
</section>
</div>
At the end you are getting to save the form with array of original records id's to save/update.
Will be happy to have any remarks for improvement.
Component:
formGroup: FormGroup;
games = [
{ keyword: 'hots', score: 9 },
{ keyword: 'xcom', score: 9 },
{ keyword: 'fallout', score: 8 }
];
constructor(private fb: FormBuilder) {}
ngOnInit() {
this.formGroup = this.fb.group(
this.games.reduce((obj, game) => {
obj[game.keyword] = [false];
return obj;
}, {})
);
const enabledGames$ = this.formGroup.valueChanges.pipe(
map(value =>
Object.entries(value)
.filter(([key, enabled]) => enabled)
.map(([key]) =>
this.games.find(({ keyword }) => keyword === key)
)
)
);
}
Template:
<form [formGroup]="formGroup">
<div *ngFor="let control of formGroup.controls | keyvalue">
<input
type="checkbox"
[formControlName]="control.key">
<label>
{{ control.key }}
</label>
</div>
</form>
I was able to accomplish this using a FormArray of FormGroups. The FormGroup consists of two controls. One for the data and one to store the checked boolean.
TS
options: options[] = [{id: 1, text: option1}, {id: 2, text: option2}];
this.fb.group({
options: this.fb.array([])
})
populateFormArray() {
this.options.forEach(option => {
let checked = ***is checked logic here***;
this.checkboxGroup.get('options').push(this.createOptionGroup(option, checked))
});
}
createOptionGroup(option: Option, checked: boolean) {
return this.fb.group({
option: this.fb.control(option),
checked: this.fb.control(checked)
});
}
HTML
This allows you to loop through the options and bind to the corresponding checked control.
<form [formGroup]="checkboxGroup">
<div formArrayName="options" *ngFor="let option of options; index as i">
<div [formGroupName]="i">
<input type="checkbox" formControlName="checked" />
{{ option.text }}
</div>
</div>
</form>
Output
The form returns data in the form {option: Option, checked: boolean}[].
You can get a list of checked options using the below code
this.checkboxGroup.get('options').value.filter(el => el.checked).map(el => el.option);
With two way binding
my.component.html
<form [formGroup]="formGroup" (ngSubmit)="onSubmit()">
<div formGroupName="options">
<mat-checkbox formControlName="myVal1">My Value 1</mat-checkbox>
<mat-checkbox formControlName="myVal2">My Value 2</mat-checkbox>
</div>
<button type="submit">Submit</button>
</form>
my.component.ts
export class ClientStatementReportComponent implements OnInit {
formGroup: FormGroup;
ngOnInit(): void {
this.formGroup = new FormGroup({
options: new FormGroup({
myVal1: new FormControl(false),
myVal2: new FormControl(false)
}),
});
}
onSubmit() {
const options = this.formGroup.value.options;
const result = Object.keys(options).filter(key => options[key])
// is array of checked elements e.g. ["myVal1"]
}
}
With one way binding (to form state)
my.component.html
<form [formGroup]="formGroup">
<mat-checkbox value="val-1" (change)="selectOption($event)">Value 1</mat-checkbox>
<mat-checkbox value="val-2" (change)="selectOption($event)">Value 2</mat-checkbox>
</form>
my.component.ts
export class MyComponent implements OnInit {
formGroup: FormGroup;
ngOnInit(): void {
this.formGroup = new FormGroup({
options: new FormControl([]),
});
}
selectOption($event: MatCheckboxChange) {
const value = $event.source.value;
const optionControl = this.formGroup.controls['options']
const options = optionControl.value as [];
if(checked){
optionControl.setValue([...options, value])
} else {
optionControl.setValue(options.filter(option => option !== value))
}
}
}
TEMPLATE PART:-
<div class="form-group">
<label for="options">Options:</label>
<div *ngFor="let option of options">
<label>
<input type="checkbox"
name="options"
value="{{option.value}}"
[(ngModel)]="option.checked"
/>
{{option.name}}
</label>
</div>
<br/>
<button (click)="getselectedOptions()" >Get Selected Items</button>
</div>
CONTROLLER PART:-
export class Angular2NgFor {
constructor() {
this.options = [
{name:'OptionA', value:'first_opt', checked:true},
{name:'OptionB', value:'second_opt', checked:false},
{name:'OptionC', value:'third_opt', checked:true}
];
this.getselectedOptions = function() {
alert(this.options
.filter(opt => opt.checked)
.map(opt => opt.value));
}
}
}
Add my 5 cents)
My question model
{
name: "what_is_it",
options:[
{
label: 'Option name',
value: '1'
},
{
label: 'Option name 2',
value: '2'
}
]
}
template.html
<div class="question" formGroupName="{{ question.name }}">
<div *ngFor="let opt of question.options; index as i" class="question__answer" >
<input
type="checkbox" id="{{question.name}}_{{i}}"
[name]="question.name" class="hidden question__input"
[value]="opt.value"
[formControlName]="opt.label"
>
<label for="{{question.name}}_{{i}}" class="question__label question__label_checkbox">
{{opt.label}}
</label>
</div>
component.ts
onSubmit() {
let formModel = {};
for (let key in this.form.value) {
if (typeof this.form.value[key] !== 'object') {
formModel[key] = this.form.value[key]
} else { //if formgroup item
formModel[key] = '';
for (let k in this.form.value[key]) {
if (this.form.value[key][k])
formModel[key] = formModel[key] + k + ';'; //create string with ';' separators like 'a;b;c'
}
}
}
console.log(formModel)
}
Template
<div>
<input name="fruits" type="checkbox" value="orange" (change)="change($event)">
<input name="fruits" type="checkbox" value="apple" (change)="change($event)">
<input name="fruits" type="checkbox" value="banana" (change)="change($event)">
</div>
Component
formGroup = this.formBuilder.group(
{
fruits: [[]] //["Orange","Banana",...]
})
change(event: Event) {
let target = (event.target as HTMLInputElement);
let array = (this.formGroup.get(target.name)?.value as Array);
if (target.checked && !array.find(element => {
return (element === target.value);
})) {
array.push(target.value)// element not exists, push (check)
}
else {
array.splice(array.findIndex(element => {
return (element === target.value);//delete element (uncheck)
}), 1)
}
}
This is how I would do it, although I always use Angular Material List
https://material.angular.io/components/list/overview
Everything comes from the factory for these tasks
I'm trying to use and understand the Aurelia ValueConverter in the context of a multi-select form. What I thought would be straight forward, has turned out to be a challenge for me.
I have a form to create a new deal which has multiple categories assigned to it via a multi-select input field. I've bound the output from the form into new_deal.categorizations (in the database deals have categories through categorizations).
Right now on create, through a 'brute force' method, I'm converting each category ID into a {category_id: id} object before posting to the API.
Example just logging the POST output:
create(){
var categorizations = this.new_deal.categorizations;
this.new_deal.categorizations = categorizations.map(function (e) {
return {category_id: e}
});
logger.debug ('POST: ', JSON.stringify(this.new_deal));
}
Example output:
POST: {"name":"new deal","categorizations":[{"category_id":"1"},{"category_id":"2"}]}
But I think this would better be accomplished through a ValueConverter.
Plunker is here with the full code but it's basically:
app.js:
export class App {
constructor(){
this.categories = [{id: 1, name: 'test1'}, {id: 2, name: 'test2'}];
this.new_deal = {
name: 'new deal',
categorizations: null,
};
}
create(){
var categorizations = this.new_deal.categorizations;
this.new_deal.categorizations = categorizations.map(function (e) {return {category_id: e}});
logger.debug ('POST: ', JSON.stringify(this.new_deal));
}
create2(){
logger.debug ('POST: ', JSON.stringify(this.new_deal));
}
}
export class CategoryToIDValueConverter {
fromView(id) {
return id ? id: null;
}
}
And app.html:
<template>
<h1>Testing ValueConverter</h1>
<h3 >New Brute Force Deal</h3>
<form role="form">
<label>Name</label>
<input type="text" placeholder="Ex. Buy One Get One Free" value.bind="new_deal.name">
<label>Categories</label>
<select value.bind="new_deal.categorizations" multiple size="2">
<option repeat.for="category of categories" value.bind="category.id">${category.name}</option>
</select>
</form>
<button type="submit" click.delegate="create()">Save</button>
<h3>New ValueConverter Deal</h3>
<form role="form">
<label>Name</label>
<input type="text" placeholder="Ex. Buy One Get One Free" value.bind="new_deal.name">
<label>Categories</label>
<select class="form-control" value.bind="new_deal.categorizations | categoryToID" multiple size="2">
<option repeat.for="category of categories" value.bind="category.id">${category.name}</option>
</select>
</form>
<button class="btn btn-success" type="submit" click.delegate="create2()">Save</button>
</template>
With this I get an output of
POST: {"name":"new deal","categorizations":["1","2"]}
In fromView in app.js, I would think I could change:
return id ? id: null;
To return an object instead of an individual value:
return id ? {category_id: id} : null
But that results in this error:
Uncaught Error: Only null or Array instances can be bound to a multi-select.
Upon further inspection, it looks like id is coming into fromView as an array...
So I modified fromView to this:
fromView(id) {
if(id){
var categorizations = [];
id.forEach(function(cat_id){
categorizations.push({category_id: cat_id})
});
logger.debug(categorizations);
logger.debug(Object.prototype.toString.call(categorizations));
return categorizations;
} else { return null; }
}
}
Trying to expect an array, and then build an array of categorization objects to return, but as you can see in this Plunker, it loses the select as you click (though the debug logs show the objects being created).
You have an array of category objects, each having a name (string) and id (number). These will be used to populate a select element that allows multiple selection:
export class App {
categories = [
{ id: 1, name: 'test1'},
{ id: 2, name: 'test2'}
];
}
<select multiple size="2">
<option repeat.for="category of categories">${category.name}</option>
</select>
The deal object is comprised of a name (string) and categorizations. Categorization objects look like this: { category_id: 1 }
export class App {
categories = [
{ id: 1, name: 'test1'},
{ id: 2, name: 'test2'}];
deal = {
name: 'new deal',
categorizations: [],
}
}
We want to bind the select element's value to the deal object's categorizations which is an array of objects. This means each of the select element's options need to have a object "value". An HTMLOptionElement's value attribute only accepts strings. Anything we assign to it will be coerced to a string. We can store the categorization object in a special model attribute which can handle any type. More info on this can be found in the aurelia docs.
<select multiple size="2">
<option repeat.for="category of categories" model.bind="{ category_id: category.id }">${category.name}</option>
</select>
Finally we need to bind the select element's value to the deal object's categorizations:
<select value.bind="deal.categorizations" multiple size="2">
<option repeat.for="category of categories" model.bind="{ category_id: category.id }">${category.name}</option>
</select>
All together, the view and view-model look like this:
export class App {
categories = [
{ id: 1, name: 'test1'},
{ id: 2, name: 'test2'}];
deal = {
name: 'new deal',
categorizations: [],
}
createDeal() {
alert(JSON.stringify(this.deal, null, 2));
}
}
<template>
<form submit.delegate="createDeal()">
<label>Name</label>
<input type="text" placeholder="Ex. Buy One Get One Free" value.bind="deal.name">
<label>Categories</label>
<select value.bind="deal.categorizations" multiple size="2">
<option repeat.for="category of categories" model.bind="{ category_id: category.id }">${category.name}</option>
</select>
<button type="submit">Save</button>
</form>
</template>
Here's a working plunker: http://plnkr.co/edit/KO3iFBostdThrHUA0QHY?p=preview
Figured it out with some help from whayes on the Aurelia Gitter channel. So I was on the right track with expecting an array in the fromView method but I also needed a toView method in the ValueConverter.
export class CategoryToIDValueConverter {
toView(cats){
if (cats){
var ids = [];
cats.forEach(function(categorization){
ids.push(categorization.category_id);
});
return ids;
} else { return null; }
}
fromView(id) {
if(id){
var categorizations = [];
id.forEach(function(cat_id){
categorizations.push({category_id: cat_id})
});
return categorizations;
} else { return null; }
}
}
I had tried that too, but I initially assumed I needed to add the converter to the select line of the form and the option line, like so:
<select class="form-control" value.bind="new_deal.categorizations | categoryToID" multiple size="2">
<option repeat.for="category of categories" value.bind="category.id">${category.name}</option>
</select>
But that's actually incorrect. I only needed to apply the categoryToID ValueConverter to the select line and it all worked as expected.
Working Plunker showing how the brute force method doesn't change the model until you click save, and the ValueConverter changes it any time you change the selection.
Final app.js
import {LogManager} from 'aurelia-framework';
let logger = LogManager.getLogger('testItems');
export class App {
constructor(){
this.categories = [{id: 1, name: 'test1'}, {id: 2, name: 'test2'}];
this.new_deal = {
name: 'new deal',
categorizations: [],
};
setInterval(() => this.debug = JSON.stringify(this.new_deal, null, 2), 100);
}
create(){
var categorizations = this.new_deal.categorizations;
this.new_deal.categorizations = categorizations.map(function (e) {return {category_id: e}});
alert(JSON.stringify(this.new_deal, null, 2));
}
create2(){
alert(JSON.stringify(this.new_deal, null, 2));
}
}
export class CategoryToIDValueConverter {
toView(cats){
if (cats){
var ids = [];
cats.forEach(function(categorization){
ids.push(categorization.category_id);
});
return ids;
} else { return null; }
}
fromView(id) {
if(id){
var categorizations = [];
id.forEach(function(cat_id){
categorizations.push({category_id: cat_id})
});
return categorizations;
} else { return null; }
}
}
Final app.html
<template>
<h1>Testing ValueConverter</h1>
<h3 >New Brute Force Deal</h3>
<form role="form">
<label>Name</label>
<input type="text" placeholder="Ex. Buy One Get One Free" value.bind="new_deal.name">
<label>Categories</label>
<select value.bind="new_deal.categorizations" multiple size="2">
<option repeat.for="category of categories" value.bind="category.id">${category.name}</option>
</select>
</form>
<button type="submit" click.delegate="create()">Save</button>
<h3>New ValueConverter Deal</h3>
<form role="form">
<label>Name</label>
<input type="text" placeholder="Ex. Buy One Get One Free" value.bind="new_deal.name">
<label>Categories</label>
<select class="form-control" value.bind="new_deal.categorizations | categoryToID" multiple size="2">
<option repeat.for="category of categories" value.bind="category.id">${category.name}</option>
</select>
</form>
<button type="submit" click.delegate="create2()">Save</button>
<!-- debug -->
<pre><code>${debug}</code></pre>
</template>