WPF Datagrid remove the addtional blank datatgridrow NewItemPlaceholderPosition.None

 private void Window_Loaded(object sender, RoutedEventArgs e)
 {
     var children = mainGd.Children;
     foreach(var child in children)
     {
         var tempGd = child as DataGrid;
         if(tempGd!=null)
         {
             var editableView = tempGd.Items as IEditableCollectionView;
             editableView.NewItemPlaceholderPosition = NewItemPlaceholderPosition.None; 
         }
     } 
 }

 

 

//xaml
<Window x:Class="WpfApp195.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:behavior="http://schemas.microsoft.com/xaml/behaviors"
        xmlns:local="clr-namespace:WpfApp195" Loaded="Window_Loaded"
        mc:Ignorable="d" WindowState="Maximized"
        Title="MainWindow" Height="450" Width="800">
    <Grid x:Name="mainGd">
        <DataGrid ItemsSource="{Binding BooksList,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                  AutoGenerateColumns="False"  >
            <behavior:Interaction.Triggers> 
                <behavior:EventTrigger EventName="SelectionChanged">
                    <behavior:CallMethodAction MethodName="DG_SelectionChanged" TargetObject="{Binding}"/>
                </behavior:EventTrigger>
            </behavior:Interaction.Triggers> 
            <DataGrid.Columns>
                <DataGridTextColumn Header="Id" Binding="{Binding Id}"/>
                <DataGridTextColumn Header="Id" Binding="{Binding Author}"/>
                <DataGridTextColumn Header="Id" Binding="{Binding ISBN}"/>
                <DataGridTextColumn Header="Id" Binding="{Binding Name}"/>
                <DataGridTextColumn Header="Id" Binding="{Binding Title}"/>
                <DataGridTextColumn Header="Id" Binding="{Binding Topic}"/>
            </DataGrid.Columns>
        </DataGrid>
    </Grid>
</Window>



//cs
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
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;

namespace WpfApp195
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            var vm = new BookViewModel();
            this.DataContext = vm;
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            var children = mainGd.Children;
            foreach(var child in children)
            {
                var tempGd = child as DataGrid;
                if(tempGd!=null)
                {
                    var editableView = tempGd.Items as IEditableCollectionView;
                    editableView.NewItemPlaceholderPosition = NewItemPlaceholderPosition.None; 
                }
            } 
        }
    }

    public class BookViewModel:INotifyPropertyChanged
    {
        public BookViewModel()
        {
            BooksList = new ObservableCollection<Book>();
            for(int i=0;i<100000;i++)
            {
                BooksList.Add(new Book()
                {
                    Id=i+1,
                    Author=$"Author_{i+1}",
                    ISBN=$"ISBN_{i+1}",
                    Name=$"Name_{i+1}",
                    Title=$"Title_{i+1}",
                    Topic=$"Topic_{i+1}"
                });
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        public void OnPropertyChanged(string propName)
        {
            var handler = PropertyChanged;
            if(handler!=null)
            {
                handler(this, new PropertyChangedEventArgs(propName));
            }  
        }


        public void DG_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var dg = sender as DataGrid;
            if(dg!=null)
            {
                var editableCollection = dg.Items as IEditableCollectionView;
                if(editableCollection!=null) 
                {
                    editableCollection.NewItemPlaceholderPosition = NewItemPlaceholderPosition.None;
                }
            }

            var items = dg.Items;
        }

        #region Properties
        private ObservableCollection<Book> booksList;
        public ObservableCollection<Book> BooksList
        {
            get
            {
                return booksList;
            }
            set
            {
                if(value!=booksList)
                {
                    booksList = value;
                    OnPropertyChanged(nameof(BooksList));
                }
            }
        }
        #endregion
    }

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

    }
}