I create a huge sheet with 1048576 rows.

If
  1. Create a Workbook;
  2. Add a Worksheet to Workbook;
  3. Fill Worksheet with 1048576 rows;
  4. Set Workbook to XamSpreadsheet.Workbook property.
It works(CreateBackground_OnClick, LoadButton_OnClick).
 
If
  1. Get Workbook from XamSpreadsheet.Workbook property.
  2. Get ActiveWorksheet;
  3. Fill ActiveWorksheet with 1048576 rows.
It throws OutOfMemoryException(CreateDirectly_OnClick).
Redo/Undo and other capabilities need memory? If so, how can avoid this?
For example:
  var workbook = spread.Workbook;
  workbook.SetCurrentFormat(WorkbookFormat.Excel2007);
  spread.BeginUpdate();  // mark update beginning
  FillWorksheet(spread.ActiveWorksheet, 1048576);
  spread.EndUpdate();    // mark update end
Between BeginUpdate() and EndUpdate(), XamSpreadsheet seems as lost memory.
Thus create some rows, just do once, also undo once.

Thank you!

What's the difference?

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<Window
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:ig="http://schemas.infragistics.com/xaml" x:Class="SpreadTest.MainWindow"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <StackPanel Orientation="Horizontal">
            <Button Margin="5" Content="Create Directly" Click="CreateDirectly_OnClick"/>
            <Button Margin="5" Content="Create Background" Click="CreateBackground_OnClick"/>
           
            <Button Margin="5" Content="Create File" Click="CreateFile_OnClick"/>
            <Button Margin="5" Content="Load File" Click="LoadButton_OnClick"/>
        </StackPanel>
       
        <ig:XamSpreadsheet x:Name="spread" Grid.Row="1"/>
    </Grid>
</Window>

using System;
using System.Diagnostics;
using System.IO;
using System.Windows;
using Infragistics.Documents.Excel;

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

        private void CreateDirectly_OnClick(object sender, RoutedEventArgs e)
        {
            var workbook = spread.Workbook;
            workbook.SetCurrentFormat(WorkbookFormat.Excel2007);
            FillWorksheet(spread.ActiveWorksheet, 1048576);
        }

        private void CreateBackground_OnClick(object sender, RoutedEventArgs e)
        {
            var workbook = new Workbook();
            workbook.SetCurrentFormat(WorkbookFormat.Excel2007);
            var sheet = workbook.Worksheets.Add(string.Format("Data Sheet"));
            FillWorksheet(sheet, 1048576);
            spread.Workbook = workbook;
        }

        private void LoadButton_OnClick(object sender, RoutedEventArgs e)
        {
            var workbook = Workbook.Load(@"F:\test.xlsx");
            if (workbook != null)
            {
                spread.Workbook = workbook;
            }
        }

        private void CreateFile_OnClick(object sender, RoutedEventArgs e)
        {
            // Create a Workbook object
            var workbook = new Workbook();
            workbook.SetCurrentFormat(WorkbookFormat.Excel2007);

            // Create a Worksheet object that contains the actual data in the workbook
            var sheet = workbook.Worksheets.Add(string.Format("Data Sheet"));
            FillWorksheet(sheet, 1048576);

            using (Stream stream = File.Open(@"F:\test.xlsx", FileMode.OpenOrCreate))
            {
                Console.WriteLine("Begin writing file ...");

                workbook.Save(stream);

                Console.WriteLine("Complete, Pressure any key to continue ...");
            }
        }

        private void FillWorksheet(Worksheet sheet, int numberOfRows)
        {
            var sw = new Stopwatch();
            sw.Start();

            for (int index = 0; index < numberOfRows; index++)
            {
                var row = sheet.Rows[index];
                row.Cells[0].Value = string.Format("{0:X8}", index);

                var timeSpan = sw.Elapsed;
                row.Cells[1].Value = timeSpan.Hours * 10000000 + timeSpan.Minutes * 100000 + timeSpan.Seconds * 1000 + timeSpan.Milliseconds;
                row.Cells[2].Value = timeSpan.TotalMilliseconds;
                row.Cells[3].Value = timeSpan.Ticks;

                row.Cells[4].Value = "F";
                row.Cells[5].Value = "400";
                row.Cells[6].Value = "50";
                row.Cells[7].Value = "50, 30, 567";
                row.Cells[8].Value = "2015-12-12";
                row.Cells[9].Value = "Feature Co. Ltd.";
                row.Cells[10].Value = "Star War Plan";
                row.Cells[11].Value = "+1-212-123-1234";
                row.Cells[12].Value = "0123456789-1234567890";
                row.Cells[13].Value = "abcdefgabcdefg hijklnm";
                row.Cells[14].Value = "OPQRST UVWXYZ";
                row.Cells[15].Value = "Description: For free use";
                row.Cells[16].Value = "Indoors use only";
                row.Cells[17].Value = "Maybe you know world trip is a nice thing, o ha ...";
                row.Cells[18].Value = "E-Mail: your.name@outlook.com";
                row.Cells[19].Value = "Say something, I feel lonely, thank you.";

                if (index % 1000 == 0)
                {
                    Console.WriteLine(index);
                }

            }

            sw.Stop();
        }

    }
}