Angular ngSwitch Directive

The Angular ngSwitch directive is used to conditionally apply styles to an element based on the value of an expression. It works by evaluating an expression and then rendering a DOM element based on the resulting value.

Here is an example of using ngSwitch to display a different message based on the value of a variable:

<div [ngSwitch]="variable">
  <p *ngSwitchCase="'value1'">This is case 1</p>
  <p *ngSwitchCase="'value2'">This is case 2</p>
  <p *ngSwitchDefault>This is the default case</p>
</div>

In this example, if variable is equal to 'value1', the div element will display the message "This is case 1". If variable is equal to 'value2', the message "This is case 2" will be displayed. If variable has any other value, the default message "This is the default case" will be displayed.

Syntax

The syntax for using ngSwitch is as follows:

<element [ngSwitch]="expression">
  <template ngSwitchCase="value1">...</template>
  <template ngSwitchCase="value2">...</template>
  <template ngSwitchDefault>...</template>
</element>

The ngSwitch directive is applied to an element and takes an expression as its value. The expression is then evaluated, and based on the result, one of the ngSwitchCase templates or the ngSwitchDefault template is rendered.

Using ngSwitchCase

The ngSwitchCase directive is used to specify a template to be rendered if the expression evaluated by ngSwitch matches the value specified in the ngSwitchCase directive.

For example:

<div [ngSwitch]="variable">
  <p *ngSwitchCase="'value1'">This is case 1</p>
  <p *ngSwitchCase="'value2'">This is case 2</p>
</div>

Using ngSwitchDefault

The ngSwitchDefault directive is used to specify a template to be rendered if the expression evaluated by ngSwitch does not match any of the values specified in the ngSwitchCase directives.