How Can I Use ngFor and ngModel on a map in Angular

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8 Answers

angularngmodelngfor
90%

Essentially, we want to learn the difference between these and learn which one to use:,Whereas ngModelChange is an Angular event, It fires when ngModel changes

Example_snippet/controller/utility/_angular.js/ <input [value]="foo" (change)=. . .
<input [value]="foo" (change)="changeFn($event)">
<input [ngModel]="bar" (ngModelChange)="modelChangeFn($event)">
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88%

We use the NgFor directive to loop over an array of items and create multiple elements dynamically from a template element,,The template element is the element the directive is attached to

Example_snippet/controller/utility/_angular.js/ @Component({ selector: 'ngfo. . .
@Component({
  selector: 'ngfor-example',
  template: `
 <ul>
  <li *ngFor="let person of people"> (1)
    {{ person.name }}
  </li>
 </ul>
 `
})
class NgForExampleComponent {
  people: any[] = [
    {
      "name": "Douglas  Pace"
    },
    {
      "name": "Mcleod  Mueller"
    },
    {
      "name": "Day  Meyers"
    },
    {
      "name": "Aguirre  Ellis"
    },
    {
      "name": "Cook  Tyson"
    }
  ];
}
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72%

The ngOptions attribute can be used to dynamically generate a list of <option> elements for the <select> element using the array or object obtained by evaluating the ngOptions comprehension expression,,By default, ngModel watches the model by reference, not value

Example_snippet/controller/utility/_angular.js/ $scope.items = [{ id: 1, l. . .
$scope.items = [{
   id: 1,
   label: 'aLabel',
   subItem: {
      name: 'aSubItem'
   }
}, {
   id: 2,
   label: 'bLabel',
   subItem: {
      name: 'bSubItem'
   }
}];
Step 2 continued with <select ng-options="item as it. . .
<select ng-options="item as item.label for item in items track by item.id" ng-model="selected"></select>
Step 3 continued with $scope.selected = $scope.items. . .
$scope.selected = $scope.items[0];
Step 4 continued with <select ng-options="item.subIt. . .
<select ng-options="item.subItem as item.label for item in items track by item.id" ng-model="selected"></select>
Step 5 continued with $scope.selected = $scope.items. . .
$scope.selected = $scope.items[0].subItem;
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65%

I have an array value display UI using ngFor,,I'm using ngModel to bind values of an array into to number inputs

Example_snippet/controller/utility/_angular.js/ [X] bug report . . .
[X] bug report
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75%

Transforms Object or Map into an array of key value pairs,,This examples show how an Object or a Map can be iterated by ngFor with the use of this keyvalue pipe

Example_snippet/controller/utility/_angular.js/ {{ input_expressi. . .
      {
         {
            input_expression | keyvalue[: compareFn]
         }
      }
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40%

ngFor by default uses object identity to compare values, this breaks when primitive values (number, string, boolean) are used, because they change identity when modified), Using trackBy allows to configure ngFor to zse the index instead of identity:,Let's suppose I have an array [1,2,3]

Example_snippet/controller/utility/_angular.js/ <div *ngFor="let x of array; l. . .
<div *ngFor="let x of array; let i = index;">
   <input type="number" [(ngModel)]="x[i]">
</div>
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22%

Let's look at how select has been set up:,Get Angular 6 by Example now with O’Reilly online learning,,We are using ngFor here to bind to an array, durations, which is in the Workout component class

Example_snippet/controller/utility/_ngmodel.js/ <select . . . name="duration" . . .
<select . . . name="duration" [(ngModel)]="exercisePlan.duration"> 
    <option *ngFor="let duration of durations" [value]="duration.value">{{duration.title}}</option> 
</select> 
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60%

Thanks for contributing an answer to Stack Overflow!, Stack Overflow Public questions & answers , Outdated Answers: accepted answer is now unpinned on Stack Overflow ,Stack Overflow em Português

Example_snippet/controller/utility/_ngmodel.js/ import { Component } from '@an. . .
import {
   Component
} from '@angular/core';

@Component({
   selector: 'my-app',
   templateUrl: './app.component.html',
   styleUrls: ['./app.component.css']
})
export class AppComponent {
   app_access = [{
      value: true,
      name: 'Cx1'
   }];
}
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