.NET MAUI Pull to Refresh and Infinite Scrolling Step by step Implementation and Top 10 Questions and Answers
 Last Update: April 01, 2025      18 mins read      Difficulty-Level: beginner

.NET MAUI: Pull to Refresh and Infinite Scrolling

Microsoft's .NET Multi-platform App UI (MAUI) is a powerful toolkit for building cross-platform applications across iOS, Android, Windows, and macOS. .NET MAUI unifies multiple frameworks such as Xamarin.Forms, UWP, Xamarin.iOS, and Xamarin.Android into a single project, making it easier for developers to create high-performance applications. Two common UI experiences that are often incorporated into mobile applications are Pull to Refresh and Infinite Scrolling. This article will guide you through implementing both features in a .NET MAUI application, detailing the necessary steps and showcasing important information.

Pull to Refresh

Pull to Refresh is a user interface pattern that allows users to refresh content by swiping down on a list or collection view. This is particularly useful in scenarios where the data in the list might have changed on the server and the user wants to update the UI without navigating away or opening another screen.

Steps to Implement Pull to Refresh:

  1. Ensure the Collection View Supports Pull to Refresh:

    • The CollectionView control in .NET MAUI supports pull-to-refresh natively. You need to ensure that the control you choose can support this feature. For instance, Listview and CollectionView both support pull-to-refresh.

  2. Enable and Configure Pull to Refresh:

    • Set the IsPullToRefreshEnabled property to true in your XAML.
    • Define a command in your ViewModel that will be executed when the user initiates a pull-to-refresh action.
<CollectionView IsPullToRefreshEnabled="True" RefreshCommand="{Binding RefreshItemsCommand}" IsRefreshing="{Binding IsRefreshing}">
    <!-- ItemsSource, ItemTemplate, etc. -->
</CollectionView>
  1. Create the Refresh Command:
    • In your ViewModel, create an ICommand that triggers the refresh logic.
public class MyViewModel : INotifyPropertyChanged
{
    public ICommand RefreshItemsCommand { get; }

    public MyViewModel()
    {
        RefreshItemsCommand = new Command(async () => await RefreshItems());
    }

    private bool _isRefreshing;
    public bool IsRefreshing
    {
        get => _isRefreshing;
        set => SetProperty(ref _isRefreshing, value);
    }

    private async Task RefreshItems()
    {
        IsRefreshing = true;
        // Fetch new data from your source here
        await Task.Delay(2000);
        IsRefreshing = false;
    }

    // Implementation of INotifyPropertyChanged
}

  1. Handle Data Fetching:

    • Inside the RefreshItems method, fetch the latest data from your data source, update your collection, and then set IsRefreshing to false.

  2. User Experience:

    • When a user pulls down the list, the IsRefreshing property will be set to true, and the control will display a refresh indicator (spinner or progress bar).

Infinite Scrolling

Infinite Scrolling is another UI pattern where content loads automatically as the user scrolls down the list or collection view. This is useful for displaying large datasets without overwhelming the user with data upfront.

Steps to Implement Infinite Scrolling:

  1. Ensure the Collection View Supports Infinite Scrolling:

    • Similar to pull-to-refresh, the CollectionView control in .NET MAUI supports infinite scrolling natively.

  2. Create a Method to Handle Loading More Data:

    • Create a method in your ViewModel that will load additional data when the user reaches the end of the list.

  3. Set Up the CollectionView to Detect When the User Reaches the End:

    • Use the Scrolled event of the CollectionView to detect when the user is near the end of the list and then call your method to load more data.
<CollectionView Scrolled="CollectionView_Scrolled">
    <!-- ItemsSource, ItemTemplate, etc. -->
</CollectionView>
  1. Implement the Scrolled Event Handler:
    • In your code-behind or ViewModel, implement the Scrolled event handler to check the scroll position and load more data when necessary.
private void CollectionView_Scrolled(object sender, ItemsViewScrolledEventArgs e)
{
    var collectionView = (CollectionView)sender;
    var scrollPosition = e.VerticalOffset + e.ViewportHeight;
    var scrollHeight = e.TotalItemsLength;

    if (scrollPosition >= scrollHeight - 1 && !IsLoadingMore)
    {
        LoadMoreItems();
    }
}
  1. Create the Load More Items Logic:
    • Implement the logic to fetch and append more data to your existing collection.
private bool _isLoadingMore;
public bool IsLoadingMore
{
    get => _isLoadingMore;
    set => SetProperty(ref _isLoadingMore, value);
}

private async void LoadMoreItems()
{
    IsLoadingMore = true;
    // Fetch additional data from your source here 
    await Task.Delay(2000);
    // Append new data to your collection
    IsLoadingMore = false;
}
  1. Loading Indicator:
    • Consider using a loading indicator or spinner to notify the user that more items are being loaded.
if (IsLoadingMore)
{
    // Show loading indicator
}

By following the steps outlined above, you can implement both Pull to Refresh and Infinite Scrolling in your .NET MAUI application. These features can significantly enhance the user experience by providing smooth, efficient data loading mechanisms. Remember to test your implementation across different platforms to ensure it works seamlessly.

Examples, Set Route and Run the Application, Then Data Flow Step by Step for Beginners: .NET MAUI Pull to Refresh and Infinite Scrolling

Introduction

Microsoft .NET Multi-platform App UI (.NET MAUI) is a framework that enables developers to create native applications for multiple platforms (iOS, Android, Windows, and macOS) with a single codebase. One common requirement in mobile applications is the ability to refresh data or load more data as the user scrolls. In this tutorial, we will explore how to implement two important features in .NET MAUI: Pull to Refresh and Infinite Scrolling.

Objective

By the end of this tutorial, you'll have a .NET MAUI application where users can:

  1. Pull Down to Refresh: Retrieve the latest data from an API or a local data source.
  2. Infinite Scroll: Load more data as the user scrolls down the list.

Prerequisites

  1. .NET 6 SDK or later installed on your machine.
  2. Visual Studio 2022: With the .NET MAUI workload installed.
  3. Basic understanding of XAML and MVVM pattern.
  4. Access to an API or a local data source: For demonstration purposes, we'll use a placeholder API.

Step-by-Step Guide

1. Set Up the .NET MAUI Project

  1. Create a New Project:

    • Open Visual Studio 2022.
    • Select Create a new project.
    • Search for .NET MAUI App and select it.
    • Click Next.
    • Enter the project name (e.g., MauiPullRefreshInfiniteScroll).
    • Choose the location to save your project.
    • Click Create.

  2. Project Structure:

    • Visual Studio will create a basic .NET MAUI project with necessary files.
    • Key files include:
      • MainPage.xaml: The main user interface for the application.
      • MainPage.xaml.cs: Code-behind for MainPage.xaml.
      • App.xaml: Application-level resources.
      • App.xaml.cs: Code for the App class.

2. Define the User Interface

In this example, we'll use a CollectionView as our main scrolling control.

  1. MainPage.xaml:

    <?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MauiPullRefreshInfiniteScroll.MainPage">
    <ScrollView>
        <CollectionView x:Name="ItemsCollectionView"
                      ItemsSource="{Binding Items}"
                      IsPullToRefreshEnabled="True"
                      CanLoadMoreItems="True"
                      RefreshRequested="ItemsCollectionView_RefreshRequested"
                      RemainingItemsThresholdReached="ItemsCollectionView_RemainingItemsThresholdReached"
                      RemainingItemsThreshold="2"
                      ItemsUpdatingScrollMode="KeepScrollOffset">
            <CollectionView.Header>
                <Label Text="Items"
                       FontSize="Large"
                       VerticalTextAlignment="Center"
                       HorizontalTextAlignment="Center"
                       Margin="10,0"/>
            </CollectionView.Header>

            <CollectionView.ItemTemplate>
                <DataTemplate>
                    <Frame BackgroundColor="LightGray"
                           Margin="10"
                           Padding="10, 0, 10, 0"
                           HasShadow="True">
                        <HorizontalStackLayout>
                            <Label Text="{Binding Name}"
                                   FontSize="Medium"
                                   VerticalTextAlignment="Center"
                                   HorizontalTextAlignment="Start"
                                   FlexLayout.Grow="1"/>
                            <Label Text="{Binding Description}"
                                   FontSize="Medium"
                                   VerticalTextAlignment="Center"
                                   HorizontalTextAlignment="Start"
                                   FlexLayout.Grow="1"/>
                        </HorizontalStackLayout>
                    </Frame>
                </DataTemplate>
            </CollectionView.ItemTemplate>
        </CollectionView>
    </ScrollView>
</ContentPage>

  2. Explanation:

    • ScrollView: Wraps the CollectionView to allow vertical scrolling.
    • CollectionView:
      • IsPullToRefreshEnabled: Enables the pull-to-refresh feature.
      • CanLoadMoreItems: Allows the collection to load additional items.
      • ItemsSource: Binds to the Items property in the ViewModel.
      • RefreshRequested: Event handler for pull-to-refresh.
      • RemainingItemsThresholdReached: Event handler for loading more items.
      • RemainingItemsThreshold: Specifies when to load more items (e.g., when 2 items are remaining).

3. Create the ViewModel

We'll use the MVVM pattern to separate the UI from the business logic.

  1. ViewModel Folder:

    • Right-click on the project in the Solution Explorer.
    • Select Add > New Folder and name it ViewModels.

  2. MainViewModel.cs:

    using System.Collections.ObjectModel;
using System.Threading.Tasks;

namespace MauiPullRefreshInfiniteScroll.ViewModels
{
    public class MainViewModel
    {
        public ObservableCollection<Item> Items { get; set; }

        private int _currentPage;
        private int _pageSize = 10;

        public MainViewModel()
        {
            Items = new ObservableCollection<Item>();
            _currentPage = 1;
            LoadData(false);
        }

        public async Task LoadData(bool isRefresh)
        {
            if (isRefresh)
            {
                Items.Clear();
                _currentPage = 1;
            }

            var newItems = await FetchItems(_currentPage, _pageSize);
            foreach (var item in newItems)
            {
                Items.Add(item);
            }

            _currentPage++;
        }

        private async Task<List<Item>> FetchItems(int page, int pageSize)
        {
            // Simulate network delay
            await Task.Delay(500);

            var items = new List<Item>();

            for (int i = 0; i < pageSize; i++)
            {
                items.Add(new Item
                {
                    Name = $"Item {(page - 1) * pageSize + i + 1}",
                    Description = $"Description of Item {(page - 1) * pageSize + i + 1}"
                });
            }

            return items;
        }
    }

    public class Item
    {
        public string Name { get; set; }
        public string Description { get; set; }
    }
}

  3. Explanation:

    • ObservableCollection<Item>: Holds the list of items.
    • LoadData(bool isRefresh): Loads data from a simulated source. Clears the list if refreshing.
    • FetchItems(int page, int pageSize): Simulates fetching data from an API. In a real application, you would replace this with actual network calls.
    • Item: A simple model class with Name and Description properties.

4. Bind the ViewModel to the View

  1. MainPage.xaml.cs:

    using MauiPullRefreshInfiniteScroll.ViewModels;
using Microsoft.Maui.Controls;

namespace MauiPullRefreshInfiniteScroll
{
    public partial class MainPage : ContentPage
    {
        private readonly MainViewModel _viewModel;

        public MainPage()
        {
            InitializeComponent();
            _viewModel = new MainViewModel();
            BindingContext = _viewModel;
        }

        private async void ItemsCollectionView_RefreshRequested(object sender, Microsoft.Maui.Controls.RefreshRequestedEventArgs e)
        {
            await _viewModel.LoadData(true);
            ItemsCollectionView.IsRefreshing = false;
        }

        private async void ItemsCollectionView_RemainingItemsThresholdReached(object sender, EventArgs e)
        {
            await _viewModel.LoadData(false);
        }
    }
}

  2. Explanation:

    • MainPage Constructor: Initializes the MainViewModel and sets it as the BindingContext.
    • ItemsCollectionView_RefreshRequested: Handles the pull-to-refresh event. Calls LoadData(true) to refresh the list and stops the refresh spinner.
    • ItemsCollectionView_RemainingItemsThresholdReached: Handles the event when more items need to be loaded. Calls LoadData(false) to append new items.

5. Run the Application

  1. Set the Target Platform:

    • Select the target platform (e.g., Android, iOS, Windows) from the toolbar.

  2. Build and Run:

    • Click the green play button or press F5 to build and run the application.
    • The app will display a list of items.
    • Pull Down to Refresh: Swipe down from the top to refresh the list.
    • Infinite Scroll: Scroll down to load more items.

6. Data Flow Step-by-Step

  1. Initialization:

    • On application startup, MainViewModel is instantiated.
    • The Items collection is populated with initial data (first page).

  2. Pull to Refresh:

    • User swipes down on the CollectionView.
    • The RefreshRequested event is triggered.
    • ItemsCollectionView_RefreshRequested method is called.
    • _viewModel.LoadData(true) is invoked, clearing the existing items and loading a new page of data.
    • IsRefreshing is set to false to stop the spinner.

  3. Infinite Scroll:

    • As the user scrolls down, the CollectionView monitors the number of remaining items.
    • When the RemainingItemsThreshold is reached (2 items remaining), the RemainingItemsThresholdReached event is triggered.
    • ItemsCollectionView_RemainingItemsThresholdReached method is called.
    • _viewModel.LoadData(false) is invoked, appending new items to the existing list.

  4. Fetching Data:

    • LoadData calls FetchItems.
    • FetchItems simulates a network request and returns a list of items.
    • New items are added to the ObservableCollection.

  5. UI Update:

    • The Items collection is an ObservableCollection, so any changes (additions, removals) automatically update the UI.
    • The CollectionView displays the updated list of items.

Conclusion

In this tutorial, we explored how to implement Pull to Refresh and Infinite Scrolling in a .NET MAUI application using the MVVM pattern. By following these steps, you can enhance the user experience in your apps by providing up-to-date and continuously loading data.

Additional Tips

  • Real API Integration: Replace the simulated data in FetchItems with calls to an actual API.
  • Error Handling: Implement error handling for network requests.
  • Loading Indicators: Consider adding loading indicators while data is being fetched.
  • Pagination Control: Implement pagination controls if you need more granular control over data loading.

Feel free to experiment and build upon this example to create more complex and dynamic applications. Happy Coding!

Top 10 Questions and Answers on .NET MAUI Pull to Refresh and Infinite Scrolling

1. What is Pull-to-Refresh in .NET MAUI and how does it work?

Answer: Pull-to-Refresh is a feature that allows users to refresh the content of their views by pulling down on the screen. In .NET MAUI, this feature can be easily integrated into ScrollView or ListView controls through the RefreshView wrapper. When users pull down, a visual indicator is shown (such as a spinning circle), and the Refreshing event is triggered where you can fetch the latest data and update the UI. The RefreshView can be configured with properties like IsPullToRefreshEnabled and Command which execute commands when the refresh is initiated.

2. Can Pull-to-Refresh be used in ListView and CollectionView controls directly, or do I need to wrap them with a RefreshView?

Answer: In .NET MAUI, you need to wrap the ListView or CollectionView with a RefreshView to use the Pull-to-Refresh feature. Directly enabling pull-to-refresh on these controls isn't natively supported. The RefreshView acts as a container control that provides the pull-to-refresh functionality to its child control.

<RefreshView Command="{Binding RefreshCommand}" IsEnabled="True">
    <ListView ItemsSource="{Binding Items}" />
</RefreshView>

3. How do I enable Infinite Scrolling in .NET MAUI and what are the prerequisites?

Answer: Infinite Scrolling in .NET MAUI allows your application to continuously load content as the user scrolls through a list. This usually involves handling the Scrolled event of the ScrollView or CollectionView when the user nears the end of the list to load additional items.

The key prerequisites are:

  • A bindable collection (e.g., ObservableCollection) to hold the data.
  • A mechanism to load more data, such as an asynchronous method that fetches more items from a source.
  • Handling the Scrolled event to trigger additional loading.

4. What are some common mistakes to avoid when implementing Pull-to-Refresh and Infinite Scrolling in .NET MAUI?

Answer: Common mistakes include:

  • Failing to set the IsEnabled and IsRefreshing properties correctly.
  • Not handling the Refreshing event for Pull-to-Refresh properly, leading to an endless refresh indicator.
  • Ignoring performance optimizations such as avoiding UI updates during refresh to keep the application responsive.
  • Incorrect event handling and race conditions in infinite scrolling, which can result in duplicate or incomplete data loading.

5. How can I provide visual feedback to users during the Pull-to-Refresh and Infinite Scrolling process?

Answer: Providing visual feedback enhances user experience by indicating that something is happening. For Pull-to-Refresh, RefreshView automatically shows a circular progress indicator. You can customize it by defining a RefreshView.HeaderTemplate.

For Infinite Scrolling, you can add an indicator at the bottom of the list, such as a ActivityIndicator, when additional data is being loaded. You can use a footer view or simply add a loader within your data template when the last item is displayed.

6. Can you show me a basic example of how to implement Pull-to-Refresh in .NET MAUI?

Answer: Here's a simplified example:

<RefreshView Command="{Binding RefreshDataCommand}" IsRefreshing="{Binding IsRefreshing}">
    <ListView ItemsSource="{Binding Items}" />
</RefreshView>

public class MainViewModel : INotifyPropertyChanged
{
    public ICommand RefreshDataCommand { get; }
    public ObservableCollection<string> Items { get; }
    public bool IsRefreshing { get; set; }

    public MainViewModel()
    {
        Items = new ObservableCollection<string> { "Item 1", "Item 2" };
        RefreshDataCommand = new Command(RefreshData);
    }

    private void RefreshData()
    {
        IsRefreshing = true;
        // Simulate network call
        Task.Delay(2000).ContinueWith((t) => {
            Items.Clear();
            Items.Add("Item 1 Refreshed");
            Items.Add("Item 2 Refreshed");
            IsRefreshing = false;
        }, TaskScheduler.FromCurrentSynchronizationContext());
    }
}

7. How do I handle infinite scrolling in .NET MAUI?

Answer: Handling infinite scrolling involves checking if the last item is in view and then loading more data.

<CollectionView x:Name="collectionView"
                ItemsSource="{Binding Items}"
                Scrolled="CollectionView_Scrolled"/>

private void CollectionView_Scrolled(object sender, ItemsViewScrolledEventArgs e)
{
    // Check if near the end
    if (e.LastVisibleItemIndex >= Items.Count - 5)
    {
        LoadMoreItems();
    }
}

private void LoadMoreItems()
{
    // Simulate async loading
    Task.Delay(1000).ContinueWith((t) => {
        for (int i = 1; i <= 10; i++)
        {
            MainThread.BeginInvokeOnMainThread(() => 
            {
                Items.Add($"Item {Items.Count + i} Loaded");
            });
        }
    });
}

8. How can I optimize performance when implementing Pull-to-Refresh and Infinite Scrolling in .NET MAUI?

Answer: Performance optimization includes:

  • Using ObservableCollection for efficient UI updates.
  • Virtualizing items in ListView/CollectionView to avoid rendering offscreen items.
  • Implementing pagination in your data fetching strategy.
  • Avoiding excessive data binding to properties that are frequently changed.
  • Debouncing scroll events to prevent too many calls to LoadMoreItems.

9. How does .NET MAUI handle Pull-to-Refresh and Infinite Scrolling on different device orientations (portrait, landscape)?

Answer: .NET MAUI handles device orientation changes gracefully, but you need to ensure that your UI layout is responsive. When the device orientation changes, the UI will resize, but the underlying logic for pull-to-refresh and infinite scrolling remains the same. Ensure that your scroll containers adjust their layout accordingly and that visual indicators are appropriately positioned for a good user experience.

10. Are there any known issues or limitations with implementing Pull-to-Refresh and Infinite Scrolling in .NET MAUI?

Answer: Some known issues or limitations include:

  • Handling of complex layouts and nested scrolling containers which can lead to unexpected behavior.
  • Performance bottlenecks when handling large datasets without proper optimization.
  • Incompatibilities or bugs in specific versions of .NET MAUI that may affect the functionality, especially in early previews.
  • Platform-specific limitations that might cause discrepancies in the user experience.

To mitigate these, always use the latest version of .NET MAUI, test extensively on targeted platforms, and consult the official documentation or community forums for additional insights.