{"id":25292,"date":"2016-04-12T10:57:33","date_gmt":"2016-04-12T17:57:33","guid":{"rendered":"https:\/\/blog.xamarin.com\/?p=25292"},"modified":"2020-09-08T09:34:04","modified_gmt":"2020-09-08T16:34:04","slug":"customizing-xamarin-forms-controls-with-effects","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/xamarin\/customizing-xamarin-forms-controls-with-effects\/","title":{"rendered":"Customizing Xamarin.Forms Controls with Effects"},"content":{"rendered":"
            Xamarin.Forms allows you to build native user interfaces for iOS, Android, and Windows from a single shared codebase using C# or XAML. Each user interface element in Xamarin.Forms is rendered natively on each platform using a renderer class that creates the corresponding native control for that platform. For example, the Xamarin.Forms control <code>Entry<\/code> is rendered as a <code>UITextField<\/code> on iOS, an <code>EditText<\/code> on Android, and a <code>TextBox<\/code> on Windows. By extending the existing renderer for a control, you can easily customize the appearance or behavior of a control. You can even create entirely new controls by defining a shared interface in Xamarin.Forms and create custom renderers to render the control on each platform natively. This approach is perfect for heavy platform-specific customizations.\n<\/code><\/pre>\n
What if you would like to perform a simple control customization? Creating a custom renderer sometimes can be a heavyweight response. Xamarin.Forms 2.1 introduces a new feature named effects<\/em> that greatly simplifies this process, allowing native controls on each platform to be more easily customized. In this blog post, you will learn how to create your own custom effect for the Slider<\/code> control in Xamarin.Forms.<\/p>\n
Introduction to Effects<\/h2>\n
Effects allow the native controls on each platform to be customized without having to implement a custom renderer. They simplify the customization of a native control and are typically used for small styling changes. Anything that can be achieved with an effect can also be achieved with a custom renderer. However, custom renderers offer more flexibility and customizations. Refer to our guidelines on which approach is right<\/a> for your customization.<\/p>\n
\"Showing<\/p>\n
Getting Started<\/h2>\n
Effects are written in platform-specific projects and are consumed in shared or PCL projects in Xamarin.Forms. Creating an effect involves two simple steps:<\/p>\n
    \n
  1. Create an effect by subclassing PlatformEffect<\/code> in the native platform you wish to customize.<\/li>\n
  2. Consume the effect by attaching it to the appropriate Xamarin.Forms control.<\/li>\n<\/ol>\n
    \"Diagram<\/p>\n
    Creating an Effect<\/h2>\n
    Effects are created in the platform-specific project. First, create a custom class that inherits from PlatformEffect<\/code> and override the OnAttached<\/code> and OnDetached<\/code> methods.<\/p>\n