Component Event In Salesforce Lightning
- parentComponent.cmp. In parent to child component communication, we can communicate by passing value from parent to child as explained above example.
- componentEventParent.js
- componentEventChild.js. STEP 1 : Create a lightning event with type COMPONENT. ...
- componentEventChild.cmp. ...
- componentEventParent.cmp. ...
- componentEventApp.app. ...
What are component events in Salesforce Lightning framework?
Component Events in Salesforce Lightning Framework. Lightning framework is based on event-driven architecture which allows to communicate between different events. Lightning events are fired from JavaScript controller actions that are triggered by a user interacting with the user interface.
What is the use of component component event?
Component Event is fired from Child Component and handled by parent component or component that fired the event. It can only be handled in the parent component. During component initialization, attribute value change, rendering, etc system events are fired automatically.
How to differentiate component event from application event in Salesforce?
Sample Component Event: Create a sample component type event. Use type=”COMPONENT” in the aura:event tag for an component event. The attribute type is the one that will differentiate Component event from Application event.
What is the capture phase of event propagation in Salesforce?
In this, the Event is first captured and handled by the source component and then propagated by application root. In this, the Event is first captured by application root and then propagated by source component. The capture phase is also known as trickling, Which recollects the propagation order.
What are component events in lightning?
A component event in the lightning component is an event that is fired by another lightning component. A component event can either be managed by the component itself or it can be managed by any of another component that is already present in the hierarchy that gets that particular event.
How many types of component event are there?
There are two types of events in the framework: Component events are handled by the component itself or a component that instantiates or contains the component. Application events are handled by all components that are listening to the event.
Why do we use component events?
Component events are used to do communication between child and parent. Application events are used to communicate any change in the component to a broader audience.
What is the difference between application event and component event?
Component events can only be handled by components above them in the containment hierarchy so their usage is more localized to the components that need to know about them. Application events are best used for something that should be handled at the application level, such as navigating to a specific record.
How do you create a component event?
To create a component event in salesforce, navigate File -> New -> Lightning Event in developerconsole. Name the event, enter the description and click submit to create lightning event. The attribute type is the one that will differentiate Component event from Application event. The events can be fired from controller.
What are the phases available with component events?
Here's the sequence of component event propagation. Event fired—A component event is fired. Capture phase—The framework executes the capture phase from the application root to the source component until all components are traversed. Any handling event can stop propagation by calling stopPropagation() on the event.
What is difference between Aura method and component event?
To communicate up the containment hierarchy, fire a component event in the child component and handle it in the parent component. Using aura:method to communicate to the parent means that multiple listeners are not possible (adding a new listener would "bump" the old listener off without warning).
How do you handle a component event?
A component event can be handled by the component that fired the event or by a component in the containment hierarchy that receives the event....Get the Source of an EventComponent Handling Its Own Event. ... Handle Component Event of Instantiated Component. ... Handling Bubbled or Captured Component Events.More items...
How do you handle a component event in lightning?
Component Event in Lightning Component | Lightning Component Communication With EVENT | aura:event1) Create Event Component.2) Register the Event ( in Child Component )3) Fire the Event ( from Child Component)4) Handle the Event (In Parent Event)Here is Code For you.
What are events used for in Salesforce?
Use Salesforce to track meetings with customers, prospects, and colleagues. Drill down from events to related records, feeds, files, contracts, and more. You can also track events in reports.
What is Aura method in Salesforce?
aura method in lightning salesforce. Use aura:method to define a method as part of a component's API. This enables you to directly call a method in a component's client-side controller instead of firing and handling a component event.
What is decorator in Salesforce?
Decorators dynamically alter the functionality of a property or function. The ability to create decorators is part of ECMAScript, but these three decorators are unique to Lightning Web Components. @api: It is used to expose a variable or functions publically and make properties reactive.
Component Event
The ceEvent.evt component event has one attribute. We’ll use this attribute to pass some data in the event when it’s fired.
Notifier Component
The c:ceNotifier component uses aura:registerEvent to declare that it may fire the component event.
Handler Component
The c:ceHandler handler component contains the c:ceNotifier component. The <aura:handler> tag uses the same value of the name attribute, cmpEvent, from the <aura:registerEvent> tag in c:ceNotifier. This wires up c:ceHandler to handle the event bubbled up from c:ceNotifier.
Put It All Together
Add the c:ceHandler component to a c:ceHandlerApp application. Navigate to the application and click the button to fire the component event.
What are custom events in Lightning?
The communication between components are handled by events. There are two types of custom events in the Lightning Framework: Component Events. Application Events. Component Events can be handled by same component or a component that instantiates or contains the component. The component events can only be registered in child component ...
What is Lightning framework?
Lightning framework is based on event-driven architecture which allows to communicate between different events. Lightning events are fired from JavaScript controller actions that are triggered by a user interacting with the user interface. The communication between components are handled by events. There are two types of custom events in ...
What is custom event in JavaScript?
A JavaScript object that emits the event. To create events, we strongly recommend using the CustomEvent interface. In Lightning web components, CustomEvent provides a more consistent experience across browsers, including Internet Explorer. It requires no setup or boilerplate, and it allows you to pass any kind of data via the detail property, ...
How to handle events in JavaScript?
To handle events, define methods in the component’s JavaScript class. After an event is fired, it can propagate up through the DOM. To understand where events can be handled, understand how they propagate. There are two ways to communicate between components that aren’t in the same DOM tree.
What is Lightning web component?
Lightning web components dispatch standard DOM events. Components can also create and dispatch custom events. Use events to communicate up the component containment hierarchy. For example, a child component, c-todo-item, dispatches an event to tell its parent, c-todo-app, that a user selected it.
Attach an Event Listener Declaratively
Declare the listener in markup in the template of the owner component, in this example, c-parent.
Attach an Event Listener Programmatically
Define both the listener and the handler function in the c-parent JavaScript.
Get a Reference to the Component That Dispatched the Event
To get a reference to the object that dispatched the event, use the Event. target property, which is part of the DOM API for events.
Event Retargeting
When an event bubbles up the DOM, if it crosses the shadow boundary, the value of Event. target changes to match the scope of the listener. This change is called “event retargeting.” The event is retargeted so the listener can’t see into the shadow DOM of the component that dispatched the event.
Listen for Changes to Input Fields
To listen for changes from an element in your template that accepts input, such as a text field ( < input > or < lightning - input > ), use the onchange event.
Remove Event Listeners
The framework takes care of managing and cleaning up listeners for you as part of the component lifecycle. However, if you add a listener to anything else (like the window object, the document object, and so on), you’re responsible for removing the listener yourself.
