Using EventCallback parameters
An event callback is a method that is passed to another method when a particular event occurs. For example, when the button on the Alert component is clicked, the @onclick event uses the OnOk parameter to determine the method that should be called. The method that the OnOK parameter references is defined in the parent component.
As previously stated, EventCallback parameters are used to share information from the child component to the parent component. They share information with their parent and notify their parent when something, such as a button click, has occurred. The parent component simply specifies the method to call when the event is triggered.
This is an example of an EventCallback parameter:
[Parameter] public EventCallback OnOk { get; set; }
The following example uses a lambda expression for the OnOk method. When the OnOk method is called, the value of the showAlert property is set to false:
<Alert Show="showAlert" OnOk="...