Install-Package Newtonsoft.Json

//WCF Producer
//D:\C\WcfService3\WcfService3\IBookService.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;

namespace WcfService3
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IBookService" in both code and config file together.
    [ServiceContract]
    public interface IBookService
    {
        [OperationContract]
        [WebGet(UriTemplate ="/getbookslist?cnt={cnt}",
            RequestFormat =WebMessageFormat.Json,
            ResponseFormat =WebMessageFormat.Json)]
        List<Book> GetBooksList(int cnt = 1000000);
    }


    public class Book
    {
        public long Id { get; set; }
        public string Name { get; set; }
        public string ISBN { get; set;  }
        public string Abstract { get; set;  }
        public string Author { 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; }
    }
}


//D:\C\WcfService3\WcfService3\BookService.svc.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using System.Threading;

namespace WcfService3
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "BookService" in code, svc and config file together.
    // NOTE: In order to launch WCF Test Client for testing this service, please select BookService.svc or BookService.svc.cs at the Solution Explorer and start debugging.
    public class BookService : IBookService
    {
        private static long id = 1;
        private static (long,long) GetStartEnd(int interval)
        {
            long end=Interlocked.Add(ref id, interval);
            long start = end - interval;
            return (start, end);
        }

        public List<Book> GetBooksList(int cnt = 1000000)
        {
            List<Book> bksList=new List<Book>();
            var (start, end) = GetStartEnd(cnt);
            for(long a=start;a<end;a++)
            {
                bksList.Add(new Book()
                {
                    Id = a,
                    Name=$"Name_{a}",
                    ISBN=$"ISBN_{a}_{Guid.NewGuid():N}",
                    Abstract=$"Abstract_{a}",
                    Author=$"Author_{a}",
                    Comment=$"Comment_{a}",
                    Content=$"Content_{a}",
                    Summary=$"Summary_{a}",
                    Title=$"Title_{a}",
                    Topic=$"Topic_{a}"
                });
            }
            System.Diagnostics.Debug.WriteLine($"{DateTime.Now}," +
                $"FirstId:{bksList.FirstOrDefault()?.Id}," +
                $"LastId:{bksList.LastOrDefault()?.Id}");
            return bksList;
        }
    }
}

//D:\C\WcfService3\WcfService3\Web.config
<?xml version="1.0"?>
<configuration>

    <appSettings>
        <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />
    </appSettings>
    <system.web>
        <compilation debug="true" targetFramework="4.8" />
        <httpRuntime targetFramework="4.8"/>
    </system.web>
    <system.serviceModel>
        <bindings>
            <webHttpBinding>
                <binding name="BookServiceWebHttpBinding"
                          openTimeout="01:00:00"
                          closeTimeout="01:00:00"
                          receiveTimeout="01:00:00"
                          sendTimeout="01:00:00"
                          maxBufferSize="2147483647"
                          maxBufferPoolSize="2147383647"
                          maxReceivedMessageSize="2147483647"
                          transferMode="Buffered">
                    <readerQuotas maxArrayLength="2147483647"
                                   maxBytesPerRead="2147483647"
                                   maxDepth="2147483647"
                                   maxNameTableCharCount="2147483647"
                                   maxStringContentLength="2147483647"/>
                    <security mode="None"/>
                </binding>
            </webHttpBinding>
        </bindings>
        <behaviors>
            <serviceBehaviors>
                <behavior name="BookServiceBehavior">
                    <!-- To avoid disclosing metadata information, set the values below to false before deployment -->
                    <serviceMetadata httpGetEnabled="true" httpsGetEnabled="true"/>
                    <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
                    <serviceDebug includeExceptionDetailInFaults="false"/>
                </behavior>
            </serviceBehaviors>

            <endpointBehaviors>
                <behavior name="BookServiceEndpointBehavior">
                    <webHttp/>
                </behavior>
            </endpointBehaviors>
        </behaviors>
        <protocolMapping>
            <add binding="basicHttpsBinding" scheme="https" />
        </protocolMapping>
        <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true" />
        <services>
            <service name="WcfService3.BookService"
                     behaviorConfiguration="BookServiceBehavior">
                <endpoint address=""
                          binding="webHttpBinding"
                          behaviorConfiguration="BookServiceEndpointBehavior"
                          bindingConfiguration="BookServiceWebHttpBinding"
                          contract="WcfService3.IBookService"/>                           
            </service>
        </services>
    </system.serviceModel>

    <system.webServer>
        <modules runAllManagedModulesForAllRequests="true"/>
        <!--
        To browse web app root directory during debugging, set the value below to true.
        Set to false before deployment to avoid disclosing web app folder information.
      -->
        <directoryBrowse enabled="true"/>
    </system.webServer>

</configuration>

http://localhost:51537/BookService.svc/getbookslist?cnt=10000

//WPF Consumer
//D:\C\WpfApp8\WpfApp8\MainWindow.xaml
<Window x:Class="WpfApp8.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:WpfApp8"
        mc:Ignorable="d"
        Title="{Binding MainTitle}"
        WindowState="Maximized">
    <Window.DataContext>
        <local:MainVM/>
    </Window.DataContext>
    <Grid>
        <DataGrid ItemsSource="{Binding BooksCollection}"
                  VirtualizingPanel.IsVirtualizing="True"
                  VirtualizingPanel.VirtualizationMode="Recycling"
                  VirtualizingPanel.CacheLength="5,5"
                  VirtualizingPanel.CacheLengthUnit="Item"
                  ScrollViewer.CanContentScroll="True"
                  ScrollViewer.IsDeferredScrollingEnabled="True"
                  SnapsToDevicePixels="True"
                  UseLayoutRounding="True"
                  AutoGenerateColumns="True"
                  CanUserAddRows="False"
                  EnableColumnVirtualization="True"
                  EnableRowVirtualization="True"
                  SelectionMode="Extended">
            <DataGrid.Resources>
                <Style TargetType="DataGridRow">
                    <Setter Property="FontSize" Value="30"/>
                    <Style.Triggers>
                        <Trigger Property="IsMouseOver" Value="True">
                            <Setter Property="FontSize" Value="40"/>
                            <Setter Property="Foreground" Value="Red"/>
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </DataGrid.Resources>
            <DataGrid.ContextMenu>
                <ContextMenu>
                    <MenuItem Header="{Binding FirstHeader}"
                              Command="{Binding FirstCmd}"
                              CommandParameter="{Binding RelativeSource={RelativeSource AncestorType=ContextMenu},
                              Path=PlacementTarget.SelectedItems}"/>
                </ContextMenu>
            </DataGrid.ContextMenu>
        </DataGrid>
    </Grid>
</Window>

//D:\C\WpfApp8\WpfApp8\MainWindow.xaml.cs
using Microsoft.Win32;
using Newtonsoft.Json;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.IO;
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;

namespace WpfApp8
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }

    public class MainVM : INotifyPropertyChanged
    {
        private static readonly HttpClient client = new HttpClient();
        private readonly object isLoadingLock = new object();
        private readonly SemaphoreSlim concurrentThrottle = new SemaphoreSlim(10, 10);
        private string originUrl = "http://localhost:51537/BookService.svc/getbookslist?cnt=";

        public MainVM()
        {
            if (DesignerProperties.GetIsInDesignMode(new DependencyObject()))
            {
                return;
            }
            _ = Task.Run(async () =>
            {
                while (true)
                {
                    await InitBooksCollectionAsync();
                    await Task.Delay(10000);
                }
            });
        }

        private DelCmd firstCmd;
        public DelCmd FirstCmd
        {
            get
            {
                if(firstCmd==null)
                {
                    firstCmd = new DelCmd(async (s) =>
                    {
                        await FirstCmdExecutedAsync(s);
                    });
                }
                return firstCmd;
            }
        }

        private async Task FirstCmdExecutedAsync(object? obj)
        { 
            await Task.Run(() =>
            {
                var items = ((System.Collections.IList)obj).Cast<Book>()?.ToList();
                if (items == null || !items.Any())
                {
                    return;
                }
                string jsonStr = JsonConvert.SerializeObject(items, Formatting.Indented);

                Application.Current?.Dispatcher?.InvokeAsync(() =>
                {
                    SaveFileDialog dlg = new SaveFileDialog();
                    dlg.Filter = $"Json Files|*.json";
                    dlg.FileName = $"Json_{DateTime.Now.ToString("yyyyMMddHHmmssffff")}";
                    if (dlg.ShowDialog() == true)
                    {
                        string jsonFile = dlg.FileName;
                        using (StreamWriter fs = new StreamWriter(jsonFile, false, Encoding.UTF8))
                        {
                            fs.WriteLine(jsonStr);
                        }
                        MessageBox.Show($"{DateTime.Now},save {items.Count} items in {jsonFile}");
                    }
                });
            }).ConfigureAwait(false); 
        }

        private async Task InitBooksCollectionAsync(int cnt = 1000000)
        {
            if (!await concurrentThrottle.WaitAsync(20000))
            {
                return;
            }
            if (IsLoading)
            {
                return;
            }

            try
            {
                IsLoading = true;
                MainTitle = $"{DateTime.Now},loading...";
                List<Book>? bksList = null;
                await Task.Run(async () =>
                {
                    string requestUrl = $"{originUrl}{cnt}";
                    string jsonStr = await client.GetStringAsync(requestUrl);
                    if (string.IsNullOrWhiteSpace(jsonStr))
                    {
                        return;
                    }
                    bksList = JsonConvert.DeserializeObject<List<Book>>(jsonStr);
                }).ConfigureAwait(false);

                if (bksList != null && bksList.Any())
                {
                    Application.Current?.Dispatcher?.InvokeAsync(() =>
                    {
                        BooksCollection = new ObservableCollection<Book>(bksList);
                        MainTitle = $"{DateTime.Now}," +
                        $"{BooksCollection.Count} items," +
                        $"FirstId:{BooksCollection.FirstOrDefault()?.Id}," +
                        $"LastId:{BooksCollection.LastOrDefault()?.Id}";
                    }, System.Windows.Threading.DispatcherPriority.Background);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show($"{DateTime.Now},ex message:{ex.Message}");
            }
            finally
            {
                IsLoading = false;
                concurrentThrottle.Release();
            }
        }

        private string firstHeader = "Save In Json";
        public string FirstHeader
        {
            get
            {
                return firstHeader;
            }
            set
            {
                if(value!=firstHeader)
                {
                    firstHeader = value;
                    OnPropertyChanged();
                }
            }
        }

        private bool isLoading;
        public bool IsLoading
        {
            get
            {
                lock (isLoadingLock)
                {
                    return isLoading;
                }
            }
            set
            {
                lock (isLoadingLock)
                {
                    if (value != isLoading)
                    {
                        isLoading = value;
                        OnPropertyChanged();
                    }
                }
            }
        }

        private ObservableCollection<Book> booksCollection;
        public ObservableCollection<Book> BooksCollection
        {
            get
            {
                return booksCollection;
            }
            set
            {
                if (value != booksCollection)
                {
                    booksCollection = value;
                    OnPropertyChanged();
                }
            }
        }

        private string mainTitle = $"{DateTime.Now}";
        public string MainTitle
        {
            get
            {
                return mainTitle;
            }
            set
            {
                if (value != mainTitle)
                {
                    mainTitle = value;
                    OnPropertyChanged();
                }
            }
        }

        public event PropertyChangedEventHandler? PropertyChanged;
        private void OnPropertyChanged([CallerMemberName] string propertyName = "")
        {
            var handler = Volatile.Read(ref PropertyChanged);
            if (handler == null)
            {
                return;
            }
            handler?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public class Book
    {
        public long Id { get; set; }
        public string Name { get; set; }
        public string ISBN { get; set; }
        public string Abstract { get; set; }
        public string Author { 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; }
    }

    public class DelCmd : ICommand
    {
        private readonly Action<object?> execute;
        private readonly Func<object?, bool>? canExecute;
        public DelCmd(Action<object?> executeValue, Func<object?, bool>? canExecuteValue = null)
        {
            execute = executeValue ?? throw new ArgumentNullException(nameof(execute));
            canExecute = canExecuteValue;
        }

        public event EventHandler? CanExecuteChanged;

        public bool CanExecute(object? parameter)
        {
            return canExecute == null ? true : canExecute(parameter);
        }

        public void Execute(object? parameter)
        {
            if (!CanExecute(parameter))
            {
                return;
            }

            if(Application.Current?.Dispatcher?.CheckAccess()==true)
            {
                execute?.Invoke(parameter);
            }
            else
            {
                Application.Current?.Dispatcher.Invoke(() =>
                {
                    execute.Invoke(parameter);
                });
            }
        }

        public void RaisedCanExecuteChanged()
        {
            var handler = Volatile.Read(ref CanExecuteChanged);
            if(handler==null)
            {
                return;
            }

            if(Application.Current?.Dispatcher?.CheckAccess()==true)
            {
                handler?.Invoke(this, EventArgs.Empty);
            }
            else
            {
                Application.Current?.Dispatcher?.Invoke(() =>
                {
                    handler?.Invoke(this, EventArgs.Empty);
                });
            }
        }
    }
}