.Net Maui Pull To Refresh And Infinite Scrolling Complete Guide

 Last Update:2025-06-23T00:00:00     .NET School AI Teacher - SELECT ANY TEXT TO EXPLANATION.    11 mins read      Difficulty-Level: beginner

Understanding the Core Concepts of .NET MAUI Pull to Refresh and Infinite Scrolling

.NET MAUI Pull to Refresh and Infinite Scrolling: Detailed Explanation and Important Information

Pull to Refresh in .NET MAUI

Implementation Steps:

  1. Enable Pull to Refresh: Use the IsPullToRefreshEnabled property of the CollectionView or ListView.
  2. Handle Refresh Command: Bind a command to the RefreshCommand property of the CollectionView or ListView to handle refresh logic.
  3. Update IsRefreshing Property: Set the IsRefreshing property of the CollectionView or ListView to control the refresh indicator.

Code Example:

<CollectionView IsPullToRefreshEnabled="True"
                RefreshCommand="{Binding RefreshCommand}"
                IsRefreshing="{Binding IsRefreshing, Mode=TwoWay}">
    ...
</CollectionView>

public class MyViewModel : BindableObject
{
    public ICommand RefreshCommand { get; }

    public bool IsRefreshing
    {
        get => _isRefreshing;
        set
        {
            _isRefreshing = value;
            OnPropertyChanged();
        }
    }

    private bool _isRefreshing;

    public MyViewModel()
    {
        RefreshCommand = new Command(ExecuteRefreshCommand);
    }

    private void ExecuteRefreshCommand()
    {
        IsRefreshing = true;
        // Refresh data here...
        IsRefreshing = false;
    }
}

Important Information:

  • The IsPullToRefreshEnabled property must be set to True to enable the feature.
  • The RefreshCommand is triggered when the user pulls to refresh.
  • Proper handling of the IsRefreshing property ensures that the UI accurately reflects the refresh state.

Infinite Scrolling in .NET MAUI

Infinite scrolling, also known as lazy loading, allows the app to load data as the user scrolls through the content, improving performance and reducing initial load times. This feature is particularly useful for displaying large lists or collections where loading all data at once can be inefficient.

Implementation Steps:

  1. Enable Infinite Scrolling: Monitor the scroll position and determine when the user has reached the end of the currently loaded data.
  2. Handle Data Loading: Use the Scrolled event of the ScrollView or ListView to detect when to load more data.
  3. Update Data Source: Append new data to the existing data to seamlessly extend the content.

Code Example:

<CollectionView Scrolled="OnCollectionViewScrolled">
    ...
</CollectionView>

private void OnCollectionViewScrolled(object sender, ItemsViewScrolledEventArgs e)
{
    var collectionView = sender as CollectionView;
    if (collectionView.IsScrollEnabled && (e.HorizontalDelta > 0 || e.VerticalDelta > 0))
    {
        var itemsThreshold = collectionView.ItemsLayout.Count - 5; // Number of items from the end
        if (e.FirstVisibleItemIndex > itemsThreshold && !_isLoadingMore)
        {
            LoadMoreData();
        }
    }
}

private bool _isLoadingMore;

private async void LoadMoreData()
{
    _isLoadingMore = true;
    // Load more data here...
    _isLoadingMore = false;
}

Important Information:

  • Use the Scrolled event to detect when the user scrolls near the end of the list.
  • Implement proper logic to determine when to load more data to avoid excessive data loading.
  • Ensure that loading more data does not interfere with the user's interaction or cause performance issues.

Conclusion

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Step-by-Step Guide: How to Implement .NET MAUI Pull to Refresh and Infinite Scrolling

1. Introduction

Pull to Refresh: This feature allows users to refresh the content by swiping down on the screen. It’s commonly used in list views or scroll views to update the data.

Infinite Scrolling: This feature loads more data automatically when the user scrolls to the bottom of the list. It helps improve performance by loading only a portion of data initially and loading more as needed.

2. Setting Up a New .NET MAUI Project

First, ensure you have the latest version of .NET SDK and .NET MAUI templates installed.

  1. Create a New Project:

    • Open Visual Studio (2022 or later).
    • Go to File > New > Project.
    • Select .NET MAUI App.
    • Click Next and configure your project details (e.g., name, location).
    • Click Create.

  2. Clean Up the Default Code:

    • Remove any unnecessary code from MainPage.xaml and MainPage.xaml.cs.
    • Ensure you have the necessary namespaces.

3. Implementing Pull to Refresh

Step 1: XAML Setup

In this example, we will use a CollectionView to demonstrate pull-to-refresh functionality.

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="MauiPullToRefresh.MainPage">
    <CollectionView x:Name="collectionView"
                    IsPullToRefreshEnabled="True"
                    RefreshCommand="{Binding RefreshDataCommand}"
                    IsRefreshing="{Binding IsRefreshing}"
                    ItemsSource="{Binding Items}">
        <CollectionView.ItemTemplate>
            <DataTemplate>
                <Label Text="{Binding .}"
                       FontSize="Medium"
                       Margin="10" />
            </DataTemplate>
        </CollectionView.ItemTemplate>
    </CollectionView>
</ContentPage>

Step 2: ViewModel Setup

Create a ViewModel to handle the logic for pull-to-refresh.

MainPageViewModel.cs:

using System.Collections.ObjectModel;
using System.Threading.Tasks;
using System.Windows.Input;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;

namespace MauiPullToRefresh;

public partial class MainPageViewModel : ObservableObject
{
    [ObservableProperty]
    private ObservableCollection<string> items;

    [ObservableProperty]
    private bool isRefreshing;

    public MainPageViewModel()
    {
        Items = new ObservableCollection<string>();
        LoadData();
    }

    [RelayCommand]
    private async Task RefreshDataCommand()
    {
        IsRefreshing = true;
        await Task.Delay(2000); // Simulate network delay
        LoadData(); // Reload data
        IsRefreshing = false;
    }

    private void LoadData()
    {
        Items.Clear();
        for (int i = 0; i < 20; i++)
        {
            Items.Add($"Item {Items.Count + 1}");
        }
    }
}

Step 3: Code-Behind Setup

Bind the ViewModel to the MainPage.

MainPage.xaml.cs:

namespace MauiPullToRefresh;

public partial class MainPage : ContentPage
{
    public MainPage(MainPageViewModel viewModel)
    {
        InitializeComponent();
        BindingContext = viewModel;
    }
}

Step 4: App Setup

Ensure the ViewModel is properly instantiated and passed to the MainPage.

App.xaml.cs:

namespace MauiPullToRefresh;

public partial class App : Application
{
    public App()
    {
        InitializeComponent();

        MainPage = new MainPage(new MainPageViewModel());
    }
}

Step 5: Run the Application

  • Build and run the application.
  • Swipe down on the list view to trigger the pull-to-refresh.
  • After a 2-second delay, the list should refresh with new items.

Pull to Refresh Demo

4. Implementing Infinite Scrolling

Step 1: Modify XAML

Add the ItemAppearing event to the CollectionView to detect when the last item is about to appear.

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="MauiPullToRefresh.MainPage">
    <CollectionView x:Name="collectionView"
                    IsPullToRefreshEnabled="True"
                    RefreshCommand="{Binding RefreshDataCommand}"
                    IsRefreshing="{Binding IsRefreshing}"
                    ItemsSource="{Binding Items}"
                    ItemAppearing="OnItemAppearing">
        <CollectionView.ItemTemplate>
            <DataTemplate>
                <Label Text="{Binding .}"
                       FontSize="Medium"
                       Margin="10" />
            </DataTemplate>
        </CollectionView.ItemTemplate>
    </CollectionView>
</ContentPage>

Step 2: Update ViewModel

Add a command to load more data and a method to handle infinite scrolling.

MainPageViewModel.cs:

using System.Collections.ObjectModel;
using System.Threading.Tasks;
using System.Windows.Input;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;

namespace MauiPullToRefresh;

public partial class MainPageViewModel : ObservableObject
{
    [ObservableProperty]
    private ObservableCollection<string> items;

    [ObservableProperty]
    private bool isRefreshing;

    [ObservableProperty]
    private bool isBusy;

    public ICommand LoadMoreDataCommand { get; }

    public MainPageViewModel()
    {
        Items = new ObservableCollection<string>();
        LoadData();
        LoadMoreDataCommand = new RelayCommand(LoadMoreData);
    }

    [RelayCommand]
    private async Task RefreshDataCommand()
    {
        if (IsBusy) return;
        IsBusy = true;
        IsRefreshing = true;
        await Task.Delay(2000); // Simulate network delay
        LoadData(); // Reload data
        IsRefreshing = false;
        IsBusy = false;
    }

    private void LoadData()
    {
        Items.Clear();
        for (int i = 0; i < 20; i++)
        {
            Items.Add($"Item {Items.Count + 1}");
        }
    }

    private void LoadMoreData()
    {
        if (IsBusy) return;
        IsBusy = true;
        for (int i = 0; i < 10; i++)
        {
            Items.Add($"Item {Items.Count + 1}");
        }
        IsBusy = false;
    }

    [ICommand]
    public void OnItemAppearing(object sender, ItemVisibilityEventArgs e)
    {
        if (Items.Count == 0)
            return;

        if (e.Item == Items[Items.Count - 1])
        {
            LoadMoreDataCommand.Execute(null);
        }
    }
}

Step 3: Code-Behind Update

Handle the ItemAppearing event in the code-behind.

MainPage.xaml.cs:

namespace MauiPullToRefresh;

public partial class MainPage : ContentPage
{
    public MainPage(MainPageViewModel viewModel)
    {
        InitializeComponent();
        BindingContext = viewModel;
    }

    private void OnItemAppearing(object sender, ItemVisibilityEventArgs e)
    {
        ((MainPageViewModel)BindingContext).OnItemAppearing(sender, e);
    }
}

Step 4: Run the Application

  • Build and run the application.
  • Scroll to the bottom of the list to load more items.

Infinite Scrolling Demo

5. Additional Tips

  • Debouncing: Consider debouncing the ItemAppearing event to prevent excessive calls to LoadMoreData.

    private DateTime _lastLoadTime = DateTime.MinValue;

[ICommand]
public void OnItemAppearing(object sender, ItemVisibilityEventArgs e)
{
    if (Items.Count == 0)
        return;

    if (e.Item == Items[Items.Count - 1])
    {
        if (DateTime.Now - _lastLoadTime < TimeSpan.FromSeconds(1))
            return;

        _lastLoadTime = DateTime.Now;
        LoadMoreDataCommand.Execute(null);
    }
}

  • Visual Feedback: Show a loading indicator (e.g., ActivityIndicator) while loading more data to enhance user experience.

    <CollectionView x:Name="collectionView"
                IsPullToRefreshEnabled="True"
                RefreshCommand="{Binding RefreshDataCommand}"
                IsRefreshing="{Binding IsRefreshing}"
                ItemsSource="{Binding Items}"
                ItemAppearing="OnItemAppearing">
    <CollectionView.ItemTemplate>
        <DataTemplate>
            <Label Text="{Binding .}"
                   FontSize="Medium"
                   Margin="10" />
        </DataTemplate>
    </CollectionView.ItemTemplate>
    <CollectionView.Footer>
        <ActivityIndicator IsRunning="{Binding IsBusy}" Color="Blue" />
    </CollectionView.Footer>
</CollectionView>

  • Error Handling: Implement error handling to manage network failures or other issues during data loading.

    [RelayCommand]
private async Task RefreshDataCommand()
{
    if (IsBusy) return;
    IsBusy = true;
    IsRefreshing = true;

    try
    {
        await Task.Delay(2000); // Simulate network request
        LoadData();
    }
    catch (Exception ex)
    {
        // Handle exception
        await Shell.Current.DisplayAlert("Error", "Failed to load data. Please try again.", "OK");
    }
    finally
    {
        IsRefreshing = false;
        IsBusy = false;
    }
}

6. Complete Example

Here is the complete code for both pull-to-refresh and infinite scrolling.

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="MauiPullToRefresh.MainPage">
    <CollectionView x:Name="collectionView"
                  IsPullToRefreshEnabled="True"
                  RefreshCommand="{Binding RefreshDataCommand}"
                  IsRefreshing="{Binding IsRefreshing}"
                  ItemsSource="{Binding Items}"
                  ItemAppearing="OnItemAppearing">
        <CollectionView.ItemTemplate>
            <DataTemplate>
                <Label Text="{Binding .}"
                     FontSize="Medium"
                     Margin="10" />
            </DataTemplate>
        </CollectionView.ItemTemplate>
        <CollectionView.Footer>
            <ActivityIndicator IsRunning="{Binding IsBusy}" Color="Blue" VerticalOptions="Center" />
        </CollectionView.Footer>
    </CollectionView>
</ContentPage>

MainPage.xaml.cs:

namespace MauiPullToRefresh;

public partial class MainPage : ContentPage
{
    public MainPage(MainPageViewModel viewModel)
    {
        InitializeComponent();
        BindingContext = viewModel;
    }

    private void OnItemAppearing(object sender, ItemVisibilityEventArgs e)
    {
        ((MainPageViewModel)BindingContext).OnItemAppearing(sender, e);
    }
}

MainPageViewModel.cs:

using System;
using System.Collections.ObjectModel;
using System.Threading.Tasks;
using System.Windows.Input;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;

namespace MauiPullToRefresh;

public partial class MainPageViewModel : ObservableObject
{
    [ObservableProperty]
    private ObservableCollection<string> items;

    [ObservableProperty]
    private bool isRefreshing;

    [ObservableProperty]
    private bool isBusy;

    public ICommand LoadMoreDataCommand { get; }

    private DateTime _lastLoadTime = DateTime.MinValue;

    public MainPageViewModel()
    {
        Items = new ObservableCollection<string>();
        LoadData();
        LoadMoreDataCommand = new RelayCommand(LoadMoreData);
    }

    [RelayCommand]
    private async Task RefreshDataCommand()
    {
        if (IsBusy) return;
        IsBusy = true;
        IsRefreshing = true;

        try
        {
            await Task.Delay(2000); // Simulate network request
            LoadData();
        }
        catch (Exception ex)
        {
            await Shell.Current.DisplayAlert("Error", "Failed to load data. Please try again.", "OK");
        }
        finally
        {
            IsRefreshing = false;
            IsBusy = false;
        }
    }

    private void LoadData()
    {
        Items.Clear();
        for (int i = 0; i < 20; i++)
        {
            Items.Add($"Item {Items.Count + 1}");
        }
    }

    private void LoadMoreData()
    {
        if (IsBusy) return;
        IsBusy = true;

        try
        {
            await Task.Delay(1000); // Simulate network request
            for (int i = 0; i < 10; i++)
            {
                Items.Add($"Item {Items.Count + 1}");
            }
        }
        catch (Exception ex)
        {
            // Handle exception
            Shell.Current?.DisplayAlert("Error", "Failed to load more data. Please try again.", "OK");
        }
        finally
        {
            IsBusy = false;
        }
    }

    [ICommand]
    public void OnItemAppearing(object sender, ItemVisibilityEventArgs e)
    {
        if (Items.Count == 0)
            return;

        if (e.Item == Items[Items.Count - 1])
        {
            if (DateTime.Now - _lastLoadTime < TimeSpan.FromSeconds(1))
                return;

            _lastLoadTime = DateTime.Now;
            LoadMoreDataCommand.Execute(null);
        }
    }
}

App.xaml.cs:

namespace MauiPullToRefresh;

public partial class App : Application
{
    public App()
    {
        InitializeComponent();

        MainPage = new MainPage(new MainPageViewModel());
    }
}

7. Conclusion

By following this step-by-step guide, you should now have a working implementation of Pull to Refresh and Infinite Scrolling in your .NET MAUI application. These features enhance user experience by providing quick and seamless data interaction.

Feel free to customize the code to fit your specific requirements!

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

1. What is Pull to Refresh in .NET MAUI?

Answer: Pull to Refresh is a user interface pattern that allows users to refresh the content of a page by dragging it down from the top. In .NET MAUI, this functionality is implemented using the RefreshView, which can wrap any scrollable view such as ListView or CollectionView.

2. How do I enable Pull to Refresh in a CollectionView?

Answer: To enable Pull to Refresh in a CollectionView, you need to set its IsPullToRefreshEnabled property to true and provide an event handler for the RefreshCommand. Here's a basic example:

<RefreshView IsPullToRefreshEnabled="True" Command="{Binding RefreshCommand}" IsRefreshing="{Binding IsRefreshing}">
    <CollectionView ItemsSource="{Binding MyItems}">
        <!-- CollectionView Content Template -->
    </CollectionView>
</RefreshView>

Ensure your ViewModel has a corresponding RefreshCommand to execute when the refresh is triggered.

3. How can I customize the appearance of the Pull to Refresh indicator?

Answer: By default, .NET MAUI uses a system-provided indicator. You cannot directly style its appearance, but you can use the RefreshColor property to change the color if supported on the target platform.

<RefreshView IsPullToRefreshEnabled="True" Command="{Binding RefreshCommand}" RefreshColor="Purple">
    <!-- Wrapped Scrollable View -->
</RefreshView>

4. What is Infinite Scrolling in .NET MAUI?

Answer: Infinite Scrolling, also known as "lazy loading," is a technique where additional content is loaded automatically as the user scrolls through the items. This is useful for handling large datasets efficiently.

5. How do I implement Infinite Scrolling in a CollectionView?

Answer: To implement infinite scrolling, subscribe to the RemainingItemsThresholdReachedCommand of the CollectionView and define a command in your ViewModel that will handle loading more data. Set the RemainingItemsThreshold property to define how close to the end of the list the user should be before triggering the load more action.

<CollectionView ItemsSource="{Binding MyItems}" RemainingItemsThreshold="0" 
                  RemainingItemsThresholdReachedCommand="{Binding LoadMoreCommand}">
    <!-- CollectionView Content Template -->
</CollectionView>

6. Can Infinite Scrolling be used with non-scrollable content like ListView?

Answer: No, ListView does not support the RemainingItemsThreshold property required for infinite scrolling. Instead, use CollectionView which offers robust support for this kind of functionality.

7. How can I make sure that the Pull to Refresh and Infinite Scrolling work correctly together?

Answer: Both functionalities can coexist in .NET MAUI, but care must be taken to avoid conflicts, especially in terms of the state management. For example, ensure the IsRefreshing state is cleared after the refresh operation completes. Also, handle LoadMoreCommand in a way that it doesn’t interfere with the refresh process, such as by disabling it while refreshing.

8. Do RefreshView and CollectionView provide built-in support for handling asynchronous operations?

Answer: Yes, .NET MAUI’s RefreshView.Command and CollectionView.RemainingItemsThresholdReachedCommand properties can be bound to asynchronous commands (using Task) which makes them suitable for performing lengthy operations like fetching data from network asynchronously.

9. Should I show a loading indicator during Pull to Refresh and Infinite Scrolling?

Answer: It is often a good practice to show a visual indicator (like a spinner) during these operations to inform the user that data is being loaded. The IsRefreshing property of RefreshView and the state management within the LoadMoreCommand can help accomplish this.

10. How can I prevent the user from pulling to refresh or loading more data when it is already in progress?

Answer: To prevent multiple concurrent refresh or load operations, bind the IsRefreshing property of RefreshView to an observable boolean in your ViewModel that represents whether a refresh operation is currently underway. Similarly, disable the LoadMoreCommand once loading more data starts until the operation completes.

public ICommand RefreshCommand { get; }

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

private async void ExecuteRefreshCommand()
{
    if (_isRefreshing) return;

    try
    {
        IsRefreshing = true;
        // Fetch fresh data here
    }
    finally
    {
        IsRefreshing = false;
    }
}

For the LoadMoreCommand, you can manage a different flag that tracks whether a load more operation is in progress and accordingly disable the command binding conditionally.

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