WPF C# construct Grid,DataGrid,Button manually

using Microsoft.Win32;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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;
using System.IO;

namespace WpfApp95
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            this.WindowState = WindowState.Maximized;
            InitGrid();
        }

        DataGrid dg { get; set; }
        private void  InitGrid()
        {
            Grid gd = new Grid(); 
            RowDefinition row1=new RowDefinition();
            RowDefinition row2=new RowDefinition();
            row2.Height = new GridLength(50); 
            gd.RowDefinitions.Add(row1);
            gd.RowDefinitions.Add(row2); 
            ColumnDefinition column1 = new ColumnDefinition();
            ColumnDefinition column2 = new ColumnDefinition();
            column2.Width = new GridLength(150);
            gd.ColumnDefinitions.Add(column1);  
            gd.ColumnDefinitions.Add(column2);
            gd.ShowGridLines= true;
            
            dg = new DataGrid();
            Grid.SetRow(dg, 0);
            Grid.SetRowSpan(dg, 2);
            Grid.SetColumn(dg, 0);
            dg.Name = "dg";
            Button btn = new Button();
            btn.Content = "Load Data";
            Grid.SetRow(btn,1); 
            Grid.SetColumn(btn,1);
            btn.Click += Btn_Click;
            gd.Children.Add(btn);
            gd.Children.Add(dg);
            this.Content = gd;
        }

        private void Btn_Click(object sender, RoutedEventArgs e)
        {
            List<Book> booksList = new List<Book>();
            for (int i = 0; i < 10000; i++)
            {
                Book bk = new Book();
                bk.Id = i + 1;
                bk.ISBN = $"ISBN_{i + 1}";
                bk.Name = $"Name_{i + 1}";
                bk.Summary = $"Summary_{i + 1}";
                bk.Title = $"Title_{i + 1}";
                bk.Topic = $"Topic_{i + 1}";
                booksList.Add(bk);
            }
            dg.ItemsSource = booksList; 
        }

        //private void Button_Click(object sender, RoutedEventArgs e)
        //{            
        //    List<Book> booksList = new List<Book>();
        //    for(int i=0;i<100;i++)
        //    {
        //        Book bk = new Book();
        //        bk.Id = i + 1;
        //        bk.ISBN = $"ISBN_{i + 1}"; 
        //        bk.Name = $"Name_{i + 1}";
        //        bk.Summary = $"Summary_{i + 1}";
        //        bk.Title = $"Title_{i + 1}";
        //        bk.Topic = $"Topic_{i + 1}";
        //        booksList.Add(bk);
        //    }
             
        //    SaveFileDialog dlg = new SaveFileDialog();
        //    dlg.FileName = $"{DateTime.Now.ToString("yyyyMMddHHmmssffff")}Books.json";
        //    if (dlg.ShowDialog() == true)
        //    {
        //        string jsonStr = JsonConvert.SerializeObject(booksList, Formatting.Indented);
        //        File.WriteAllText(dlg.FileName, jsonStr);
        //    }
        //}

    }

    public class Book
    {
        public int Id { get; set; }
        public string ISBN { get; set; }
        public string Name { get; set; }
        public string Summary { get; set; }
        public string Title { get; set; }
        public string Topic { get; set; }
    }

}