Mastering CollectionView in Xamarin.Forms

What is CollectionView?

CollectionView is a powerful graphical control that allows you to present lists of data in a flexible and high-performance way. It offers significant improvements in performance and flexibility compared to its predecessor, ListView. With features like pull-to-refresh, empty views, and customizable layouts, CollectionView is a must-have for any Xamarin.Forms developer.

The Basic Structure of CollectionView

Before we dive deeper, let’s break down the building blocks of CollectionView. This graphical control consists of three key elements:

• Items Source: The data source that provides the items to be displayed.
• Item Template: A template that defines the appearance of each item.
• Layout: The layout that arranges the items.

Preparing Data for CollectionView

Let’s create a simple example to get started. Imagine we want to display a list of students with names, last names, and telephone numbers. We’ll create a Student class, a ViewModel to fill it with mock data, and finally, a CollectionView to display the information.

public class Student
{
    public string Name { get; set; }
    public string LastName { get; set; }
    public string TelephoneNumber { get; set; }
}

public class StudentViewModel
{
    public ObservableCollection<Student> Students { get; set; }

    public StudentViewModel()
    {
        Students = new ObservableCollection<Student>
        {
            new Student { Name = "John", LastName = "Doe", TelephoneNumber = "123-456-7890" },
            new Student { Name = "Jane", LastName = "Doe", TelephoneNumber = "098-765-4321" },
            //...
        };
    }
}

Essential CollectionView Properties

CollectionView has several properties that make it a joy to work with. Let’s explore some of the most useful ones:

Pull-to-Refresh

Use the IsRefreshing property to handle a bool value and display a loading indicator when the user scrolls down.

<CollectionView IsRefreshing="{Binding IsRefreshing}">
    
</CollectionView>

EmptyView

Use the EmptyView property to display a message when there’s no data available.

<CollectionView.EmptyView>
    <Label Text="No students found."/>
</CollectionView.EmptyView>

Setting the ItemsLayout

Use the ItemsLayout property to choose the orientation of your list, whether it’s vertical or horizontal.

<CollectionView ItemsLayout="VerticalList">
    
</CollectionView>

With these properties and features, CollectionView offers endless possibilities for presenting data in a visually appealing way. Start exploring the world of CollectionView today and discover how it can revolutionize your Xamarin.Forms development experience!