■ CollectionView 클래스의 RemainingItemsThresholdReached 이벤트를 사용해 데이터를 점진적으로 로드하는 방법을 보여준다.
▶ Monkey.cs
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namespace TestProject; /// <summary> /// 원숭이 /// </summary> public class Monkey { //////////////////////////////////////////////////////////////////////////////////////////////////// Property ////////////////////////////////////////////////////////////////////////////////////////// Public #region 명칭 - Name /// <summary> /// 명칭 /// </summary> public string Name { get; set; } #endregion #region 위치 - Location /// <summary> /// 위치 /// </summary> public string Location { get; set; } #endregion #region 이미지 URL - ImageURL /// <summary> /// 이미지 URL /// </summary> public string ImageURL { get; set; } #endregion } |
▶ ImageSourceConverter.cs
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using System.Globalization; namespace TestProject; /// <summary> /// 이미지 URL→이미지 소스 변환자 /// </summary> public class ImageSourceConverter : IValueConverter { //////////////////////////////////////////////////////////////////////////////////////////////////// Method ////////////////////////////////////////////////////////////////////////////////////////// Public #region 변환하기 - Convert(sourceValue, targetType, parameter, cultureInfo) /// <summary> /// 변환하기 /// </summary> /// <param name="sourceValue">소스 값</param> /// <param name="targetType">타겟 타입</param> /// <param name="parameter">매개 변수</param> /// <param name="cultureInfo">문화 정보</param> /// <returns>변환 값</returns> public object Convert(object sourceValue, Type targetType, object parameter, CultureInfo cultureInfo) { string imageURL = sourceValue as string; if(string.IsNullOrWhiteSpace(imageURL)) { return null; } return ImageSource.FromUri(new Uri(imageURL)); } #endregion #region 역변환하기 - ConvertBack(sourceValue, targetType, parameter, cultureInfo) /// <summary> /// 역변환하기 /// </summary> /// <param name="sourceValue">소스 값</param> /// <param name="targetType">타겟 타입</param> /// <param name="parameter">매개 변수</param> /// <param name="cultureInfo">문화 정보</param> /// <returns>역변환 값</returns> public object ConvertBack(object sourceValue, Type targetType, object parameter, CultureInfo cultureInfo) { throw new NotImplementedException(); } #endregion } |
▶ MainPage.xaml
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<?xml version="1.0" encoding="utf-8" ?> <ContentPage x:Class="TestProject.MainPage" xmlns="http://schemas.microsoft.com/dotnet/2021/maui" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:local="clr-namespace:TestProject"> <ContentPage.Resources> <local:ImageSourceConverter x:Key="ImageSourceConverterKey" /> </ContentPage.Resources> <CollectionView x:Name="collectionView"> <CollectionView.ItemTemplate> <DataTemplate> <Grid Padding="10" RowDefinitions="Auto" ColumnDefinitions="Auto,10,*"> <Image Grid.Column="0" WidthRequest="60" HeightRequest="60" Aspect="AspectFill" Source="{Binding ImageURL, Converter={StaticResource ImageSourceConverterKey}}" /> <StackLayout Grid.Column="2"> <Label FontAttributes="Bold" FontSize="16" Text="{Binding Name}" /> <Label VerticalOptions="End" FontAttributes="Italic" Text="{Binding Location}" /> </StackLayout> </Grid> </DataTemplate> </CollectionView.ItemTemplate> </CollectionView> </ContentPage> |
▶ MainPage.xaml.cs
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namespace TestProject; /// <summary> /// 메인 페이지 /// </summary> public partial class MainPage : ContentPage { //////////////////////////////////////////////////////////////////////////////////////////////////// Constructor ////////////////////////////////////////////////////////////////////////////////////////// Public #region 생성자 - MainPage() /// <summary> /// 생성자 /// </summary> public MainPage() { InitializeComponent(); List<Monkey> list = new List<Monkey>(); for(int i = 0; i < 10; i++) { list.Add ( new Monkey { Name = "Baboon", Location = "Africa and Asia", ImageURL = "https://upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Papio_anubis_%28Serengeti%2C_2009%29.jpg/200px-Papio_anubis_%28Serengeti%2C_2009%29.jpg" } ); list.Add ( new Monkey { Name = "Capuchin Monkey", Location = "Central and South America", ImageURL = "https://upload.wikimedia.org/wikipedia/commons/thumb/4/40/Capuchin_Costa_Rica.jpg/200px-Capuchin_Costa_Rica.jpg" } ); list.Add ( new Monkey { Name = "Blue Monkey", Location = "Central and East Africa", ImageURL = "https://upload.wikimedia.org/wikipedia/commons/thumb/8/83/BlueMonkey.jpg/220px-BlueMonkey.jpg" } ); } this.collectionView.ItemsSource = list; this.collectionView.RemainingItemsThreshold = 1; this.collectionView.RemainingItemsThresholdReached += collectionView_RemainingItemsThresholdReached; } #endregion //////////////////////////////////////////////////////////////////////////////////////////////////// Method ////////////////////////////////////////////////////////////////////////////////////////// Private #region 컬렉션 뷰 잔혀 항목 임계치 도달시 처리하기 - collectionView_RemainingItemsThresholdReached(sender, e) /// <summary> /// 컬렉션 뷰 잔혀 항목 임계치 도달시 처리하기 /// </summary> /// <param name="sender">이벤트 발생자</param> /// <param name="e">이벤트 인자</param> private async void collectionView_RemainingItemsThresholdReached(object sender, EventArgs e) { await DisplayAlert("INFORMATION", "RemainingItemsThresholdReached 이벤트가 발생했습니다.", "확인"); this.collectionView.RemainingItemsThreshold = -1; // 테스트를 위한 설정이다. } #endregion } |
