public class DelCommand : ICommand {private Action<object?>? syncExecute;private readonly Func<object?, Task> asyncExecute;private Predicate<object?>? canExecute;public DelCommand(Action<object?>? executeValue, Predicate<object?>? canExecuteValue = null){syncExecute = executeValue ?? throw new ArgumentNullException(nameof(executeValue));canExecute = canExecuteValue;}public DelCommand(Func<object?, Task> asyncExecuteValue, Predicate<object?>? canExecuteValue = null){asyncExecute = asyncExecuteValue ?? throw new ArgumentNullException(nameof(asyncExecuteValue));canExecute = canExecuteValue;}public event EventHandler? CanExecuteChanged{add{CommandManager.RequerySuggested += value;}remove{CommandManager.RequerySuggested -= value;}}public bool CanExecute(object? parameter){return canExecute == null ? true : canExecute(parameter);}public async void Execute(object? parameter){if (!CanExecute(parameter)){return;}if (asyncExecute != null){await asyncExecute(parameter);}else if (syncExecute != null){syncExecute(parameter);}} }private ICommand mouseDownCommand; public ICommand MouseDownCommand {get{if (mouseDownCommand == null){mouseDownCommand = new DelCommand(MouseDownCommandExecuted);}return mouseDownCommand;} }private async Task MouseDownCommandExecuted(object? obj) {var btnEventArgs = obj as MouseButtonEventArgs;if (btnEventArgs != null){await InitBooksCollectionAsync();string msg = $"MinId:{BooksCollection.OrderBy(x => x.Id).FirstOrDefault()?.Id}\n" +$"MaxId:{BooksCollection.OrderByDescending(x => x.Id).FirstOrDefault()?.Id}";MessageBox.Show($"{msg}", $"{DateTime.Now}");} }private async Task InitBooksCollectionAsync() {string dataUrl = "https://localhost:7146/api/book";using (HttpClient client = new HttpClient()){string jsonStr = await client.GetStringAsync(dataUrl);if (!string.IsNullOrWhiteSpace(jsonStr)){List<Book>? bksList = JsonConvert.DeserializeObject<List<Book>>(jsonStr);if (bksList != null && bksList.Any()){BooksCollection = new ObservableCollection<Book>(bksList);MainTitle = $"{DateTime.Now},loaded last idx:{bksList.OrderByDescending(x => x.Id).FirstOrDefault()?.Id}";}}} }
//WebAPI namespace WebApplication2.Models {public class Book{public int Id { get; set; }public string Name { get; set; }public string ISBN { get; set; }public string Comment { get; set; }public string Content { get;set; } public string Summary { get; set; }public string Title { get; set; }public string Topic { get; set; }} } using WebApplication2.Models;namespace WebApplication2.Services {public class BookService:IDisposable{int idx = 0;private int GetIdx(){return Interlocked.Increment(ref idx);}public List<Book> GetBooksList(int cnt=10000){List<Book> booksList=new List<Book>();for(int i=0;i<cnt;i++){int a=GetIdx();booksList.Add(new Book(){Id = a,Name = $"Name_{a}",ISBN = $"ISBN_{a}_{Guid.NewGuid():N}",Comment =$"Comment_{a}",Content=$"Content_{a}",Title=$"Title_{a}",Topic=$"Topic_{a}"});}return booksList;}public void Dispose(){idx = 0;}} } using Microsoft.AspNetCore.Mvc; using WebApplication2.Models; using WebApplication2.Services;namespace WebApplication2.Controllers {[ApiController][Route("api/[controller]")]public class BookController : Controller{private BookService bkService;public BookController(BookService bkServiceValue){bkService= bkServiceValue;}[HttpGet][ProducesResponseType(StatusCodes.Status200OK)]public ActionResult<List<Book>> GetBooksList(){var bksList = bkService.GetBooksList();return Ok(bksList);}} }using WebApplication2.Services;namespace WebApplication2 {public class Program{public static void Main(string[] args){var builder = WebApplication.CreateBuilder(args);// Add services to the container. builder.Services.AddControllers();// Learn more about configuring OpenAPI at https://aka.ms/aspnet/openapi builder.Services.AddOpenApi();builder.Services.AddSingleton<BookService>();var app = builder.Build();// Configure the HTTP request pipeline.if (app.Environment.IsDevelopment()){app.MapOpenApi();}app.UseHttpsRedirection();app.UseAuthorization();app.MapControllers();app.Run();}} }//WPF <Window x:Class="WpfApp7.MainWindow"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:d="http://schemas.microsoft.com/expression/blend/2008"xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"xmlns:local="clr-namespace:WpfApp7"xmlns:behavior="http://schemas.microsoft.com/xaml/behaviors"mc:Ignorable="d"WindowState="Maximized"Title="{Binding MainTitle}" Height="450" Width="800"><behavior:Interaction.Triggers><behavior:EventTrigger EventName="MouseDown"><behavior:InvokeCommandActionCommand="{Binding MouseDownCommand}"PassEventArgsToCommand="True"/></behavior:EventTrigger></behavior:Interaction.Triggers><Window.DataContext><local:MainVM/></Window.DataContext><Grid><DataGrid ItemsSource="{Binding BooksCollection}"IsReadOnly="True"VirtualizingPanel.IsVirtualizing="True"VirtualizingPanel.VirtualizationMode="Recycling"EnableRowVirtualization="True"EnableColumnVirtualization="True"ScrollViewer.CanContentScroll="True"ScrollViewer.IsDeferredScrollingEnabled="True"VirtualizingPanel.CacheLength="2,2"VirtualizingPanel.CacheLengthUnit="Item"AutoGenerateColumns="True"CanUserAddRows="False"><DataGrid.Resources><Style TargetType="DataGridRow"><Setter Property="FontSize" Value="30"/><Style.Triggers><Trigger Property="IsMouseOver" Value="True"><Setter Property="FontSize" Value="50"/><Setter Property="Foreground" Value="Red"/></Trigger></Style.Triggers></Style></DataGrid.Resources><behavior:Interaction.Triggers><behavior:EventTrigger EventName="PreviewMouseDown"><behavior:InvokeCommandActionCommand="{Binding MouseDownCommand}"PassEventArgsToCommand="True"/></behavior:EventTrigger></behavior:Interaction.Triggers></DataGrid></Grid> </Window>using System.Collections.ObjectModel; using System.ComponentModel; using System.Net.Http; using System.Runtime.CompilerServices; using System.Text; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; using Newtonsoft.Json;namespace WpfApp7 {/// <summary>/// Interaction logic for MainWindow.xaml/// </summary>public partial class MainWindow : Window{public MainWindow(){InitializeComponent();}}public class MainVM : INotifyPropertyChanged{public MainVM(){_=InitBooksCollectionAsync();}private ICommand mouseDownCommand;public ICommand MouseDownCommand{get{if (mouseDownCommand == null){mouseDownCommand = new DelCommand(MouseDownCommandExecuted);}return mouseDownCommand;}}private async Task MouseDownCommandExecuted(object? obj){var btnEventArgs = obj as MouseButtonEventArgs;if (btnEventArgs != null){await InitBooksCollectionAsync();string msg = $"MinId:{BooksCollection.OrderBy(x => x.Id).FirstOrDefault()?.Id}\n" +$"MaxId:{BooksCollection.OrderByDescending(x => x.Id).FirstOrDefault()?.Id}";MessageBox.Show($"{msg}", $"{DateTime.Now}");}}private async Task InitBooksCollectionAsync(){string dataUrl = "https://localhost:7146/api/book";using (HttpClient client = new HttpClient()){string jsonStr = await client.GetStringAsync(dataUrl);if (!string.IsNullOrWhiteSpace(jsonStr)){List<Book>? bksList = JsonConvert.DeserializeObject<List<Book>>(jsonStr);if (bksList != null && bksList.Any()){BooksCollection = new ObservableCollection<Book>(bksList);MainTitle = $"{DateTime.Now},loaded last idx:{bksList.OrderByDescending(x => x.Id).FirstOrDefault()?.Id}";}}}}private string mainTitle="";public string MainTitle{get{return mainTitle;}set{if (value != mainTitle){mainTitle = value;OnPropertyChanged();}}}private ObservableCollection<Book> booksCollection;public ObservableCollection<Book> BooksCollection{get{return booksCollection;}set{if (value != booksCollection){booksCollection = value;OnPropertyChanged();}}}public event PropertyChangedEventHandler? PropertyChanged;private void OnPropertyChanged([CallerMemberName] string propertyName = ""){var handler = PropertyChanged;if (handler != null){handler?.Invoke(this, new PropertyChangedEventArgs(propertyName));}}}public class DelCommand : ICommand{private Action<object?>? syncExecute;private readonly Func<object?, Task> asyncExecute;private Predicate<object?>? canExecute;public DelCommand(Action<object?>? executeValue, Predicate<object?>? canExecuteValue = null){syncExecute = executeValue ?? throw new ArgumentNullException(nameof(executeValue));canExecute = canExecuteValue;}public DelCommand(Func<object?, Task> asyncExecuteValue, Predicate<object?>? canExecuteValue = null){asyncExecute = asyncExecuteValue ?? throw new ArgumentNullException(nameof(asyncExecuteValue));canExecute = canExecuteValue;}public event EventHandler? CanExecuteChanged{add{CommandManager.RequerySuggested += value;}remove{CommandManager.RequerySuggested -= value;}}public bool CanExecute(object? parameter){return canExecute == null ? true : canExecute(parameter);}public async void Execute(object? parameter){if (!CanExecute(parameter)){return;}if (asyncExecute != null){await asyncExecute(parameter);}else if (syncExecute != null){syncExecute(parameter);}}}public class Book{public int Id { get; set; }public string Name { get; set; }public string ISBN { get; set; }public string Comment { get; set; }public string Content { get; set; }public string Summary { get; set; }public string Title { get; set; }public string Topic { get; set; }} }