Hands-On Mobile Development with .NET Core

Creating behaviors

Behaviors are an eloquent use of the decorator pattern, allowing the developers to modify the Xamarin.Forms controls without having to create derived controls.

A simple example of creating a behavior would be to implement a validation behavior in our LoginView. As you may remember, we actually used the Command.CanExecute delegate to validate our fields. In this example, we will separate the validators for the email field and the password field. This way, we can allow the UI to give feedback to the user as a result of an incorrect entry. This would be more user-friendly than only disabling the login window. To set this up, follow these steps:

1. First, we need to create a validation rule infrastructure, starting with the validation ...