Class Binding

  • Class binding is a way to bind a class to an element’s class list in the template. It allows you to dynamically set the classes of an element based on component state.

Here’s an example of using class binding:

<div [class.selected]="isSelected">This div is selected</div>

In this example, the selected class will be added to the div element’s class list if isSelected is true, and removed if isSelected is false.

You can also bind to multiple classes using class binding:

<div [class.selected]="isSelected" [class.highlighted]="isHighlighted">This div is selected and highlighted</div>

Another advantage of class binding is that it can help you to avoid using a lot of conditional statements in your templates. Instead of using an *ngIf directive to add or remove an element based on some condition, you can use class binding to apply or remove a CSS class. This can make your templates simpler and easier to read.

For example, consider the following template that uses an *ngIf directive to show or hide a message based on the value of a component property:

<div *ngIf="showMessage">
  This is the message.
</div>

You can rewrite this template using class binding as follows:

<div [class.hidden]="!showMessage">
  This is the message.
</div>

In this example, the hidden class will be applied to the div element if the showMessage property is false, and it will be removed if the showMessage property is true. This can be more concise and easier to read than using an *ngIf directive.

Advantages of using class binding:

  • It allows you to dynamically set the classes of an element based on component state.
  • It helps keep the template clean by separating the presentation of an element from its behavior.
  • It makes it easier to maintain and modify the styles of your application, since you can centralize the logic for adding and removing classes in the component rather than scattering it throughout the template.
Class Binding