Modifying the property value based on the selected item from a dropdown menu in Angular 2

Question

Modifying the property value based on the selected item from a dropdown menu in Angular 2

I am brand new to Angular 2 and I have come across the following code snippet.

<select name="shape_id" (change)="changeShape()">
    <option *ngFor="let shape of shapes" [ngValue]="shape.name">
      {{shape.name}}
    </option>
  </select>

When selecting an option from the dropdown, I would like to assign the selected shape ID to a property called shapeId in my component.

The available shapes are as follows:

[{"name":"aa","id":"1"},{"name":"bb","id":"3"},{"name":"cc","id":"2"}]

If anyone could assist me with this, it would be greatly appreciated.

angular typescript

Answer 1

Answer №1

This particular solution allows for the direct binding of the chosen object to a component property, giving flexibility to handle the selected shape in any way within the event handler.

Key Excerpts:

To begin, let's define the structure:

interface Shape {
  name: string;
  id: number;
}

Snippet of Template code:

<select (change)="changeShape()" [(ngModel)]="selectedShape">
  <option *ngFor="let shape of shapes" [ngValue]="shape">
    {{shape.name}}
  </option>
</select>
<p>Selected shape: {{shapeName}}</p>

Snippet of Component code:

private selectedShape: Shape;

private shapes : Shape[] = [
  {name: "circle", id: 0},
  {name: "rectangle", id: 1}
];

private shapeName: string;

public changeShape() {
  this.shapeName = this.selectedShape.name;
}

Answer 2

This particular solution allows for the direct binding of the chosen object to a component property, giving flexibility to handle the selected shape in any way within the event handler.

Key Excerpts:

To begin, let's define the structure:

interface Shape {
  name: string;
  id: number;
}

Snippet of Template code:

<select (change)="changeShape()" [(ngModel)]="selectedShape">
  <option *ngFor="let shape of shapes" [ngValue]="shape">
    {{shape.name}}
  </option>
</select>
<p>Selected shape: {{shapeName}}</p>

Snippet of Component code:

private selectedShape: Shape;

private shapes : Shape[] = [
  {name: "circle", id: 0},
  {name: "rectangle", id: 1}
];

private shapeName: string;

public changeShape() {
  this.shapeName = this.selectedShape.name;
}

Answer 3

Answer №2

<select name="shape_id" (change)="handleChange($event.target.value)"> // incorporate this into the change method
    <option *ngFor="let shape of shapes" [ngValue]="shape.id">
      {{shape.name}}
    </option>
  </select>

In Component

selectedVal: string;

handleChange(selectedValue: string) {
    this.selectedVal = selectedValue;
}

You can also choose either option as they will both work

<select name="shape_id" [(ngModel)]="selectedItem"> // utilize ngModel in this case
    <option *ngFor="let shape of shapes" [ngValue]="shape.id">
      {{shape.name}}
    </option>
  </select>

The variable "selectedItem" will be within the Component

Update Post-Comment

<select name="shape_id" (change)="handleChange(i)"> // include this in the change method
    <option *ngFor="let shape of shapes; let i = index" [ngValue]="shape.id">
      {{shape.name}}
    </option>
  </select>

Pass the index value and then you can reference the id in the component to update "selected value" to "selected index: number"

Answer 4

<select name="shape_id" (change)="handleChange($event.target.value)"> // incorporate this into the change method
    <option *ngFor="let shape of shapes" [ngValue]="shape.id">
      {{shape.name}}
    </option>
  </select>

In Component

selectedVal: string;

handleChange(selectedValue: string) {
    this.selectedVal = selectedValue;
}

You can also choose either option as they will both work

<select name="shape_id" [(ngModel)]="selectedItem"> // utilize ngModel in this case
    <option *ngFor="let shape of shapes" [ngValue]="shape.id">
      {{shape.name}}
    </option>
  </select>

The variable "selectedItem" will be within the Component

Update Post-Comment

<select name="shape_id" (change)="handleChange(i)"> // include this in the change method
    <option *ngFor="let shape of shapes; let i = index" [ngValue]="shape.id">
      {{shape.name}}
    </option>
  </select>

Pass the index value and then you can reference the id in the component to update "selected value" to "selected index: number"

Answer 5

Answer №3

when setting up your design -

<select name="form_id" (update)="updateDesign($event.target.value)">
  <option *ngFor="let form of forms" [value]="form.id">
    {{form.name}}
  </option>
</select>

within your element -

designId: string;

updateDesign(id: string) {
    this.designId = id;
  }

Answer 6

when setting up your design -

<select name="form_id" (update)="updateDesign($event.target.value)">
  <option *ngFor="let form of forms" [value]="form.id">
    {{form.name}}
  </option>
</select>

within your element -

designId: string;

updateDesign(id: string) {
    this.designId = id;
  }

Modifying the property value based on the selected item from a dropdown menu in Angular 2

Answer №1

Answer №2

Answer №3

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