In Angular, the ComponentFactoryResolver service allows you to dynamically load a component at runtime. This powerful tool allows you to create and render a component without the need to define it in the template. This can be useful in a variety of situations, such as when you need to load a component based on user interaction or when you need to load a component based on data from an API.
The first step in using the ComponentFactoryResolver service is to import it and the ViewContainerRef from @angular/core. The ViewContainerRef is a container where we will insert the dynamically created component.
import { ComponentFactoryResolver, ViewContainerRef } from '@angular/core';
Next, you'll need to create a reference to the ViewContainerRef in your component. You can do this by injecting it in the constructor and storing it as a property of the class.
constructor(private resolver: ComponentFactoryResolver, private container: ViewContainerRef) {}
You can use the resolver.resolveComponentFactory() method to create a ComponentFactory for the component that you want to load. This method takes the component type as a parameter and returns a factory that you can use to create an instance of the component.
const factory = this.resolver.resolveComponentFactory(DynamicComponent);
``
Next, you can use the createComponent() method of the ViewContainerRef to create an instance of the component and insert it into the view. The createComponent() method takes the component factory as a parameter and returns a reference to the dynamically created component instance.
const componentRef = this.container.createComponent(factory);
You can access the properties and methods of the dynamically created component instance by using the instance property of the component reference. For example, if your component has a property called message, you can set it as follows:
componentRef.instance.message = "Hello World!";
You can also access the component's output events using the componentRef.instance.event.subscribe() method. For example, if your component has an output event called onSave, you can subscribe to it as follows:
componentRef.instance.onSave.subscribe((data) => {
console.log(data);
});
Finally, you can remove the dynamically created component from the view using the destroy() method of the component reference.
componentRef.destroy();
In conclusion, the ComponentFactoryResolver service provides a powerful tool for dynamically loading components in Angular. By using this service, you can create and render a component at runtime, giving you greater control over the components that are displayed in your application.