A Comparison of IronXL and NPOI

NPOI Installation

Installing NPOI with NuGet

To install NPOI through NuGet, open the Visual Studio developer command prompt and enter the following:

Install-Package NPOI -Version x.x.x

Figure 1 - NuGet NPOI Installation

Visual Studio NuGet Package Manager and NPOI

Use the following steps to install IronXL or NPOI via the NuGet Package Manager in Visual Studio:

• Right-click the project in the Solution Explorer
• Select Manage NuGet Packages
• Browse for your Package
• Click Install

Figure 2 - NuGet Package Manager for NPOI

IronXL Installation

Downloading IronXL

To download IronXL, navigate to the following URL and click the "Download" button.

Figure 3 - Download IronXL

Installing IronXL with NuGet

To install IronXL through NuGet, open the Visual Studio developer command prompt and enter the following:

Install-Package IronXL.Excel -Version x.x.x

Figure 4 - NuGet IronXL Installation

Visual Studio NuGet Package Manager and IronXL

Use the following steps to install IronXL via the NuGet Package Manager in Visual Studio:

• Right-click the project in the Solution Explorer
• Select Manage NuGet Packages
• Browse for your Package
• Click Install

Figure 5 - NuGet Package Manager for IronXL

Reading an Excel file with NPOI

The following code demonstrates how to read an Excel file and display its contents with NPOI. Add the following code and include the necessary namespaces:

using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using System.Data;
using System.IO;
using System.Collections.Generic;

using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using System.Data;
using System.IO;
using System.Collections.Generic;

The below code reads an existing Excel file and displays it inside a data grid view.

public void ReadExcelNPOI()
{
    DataTable dtTable = new DataTable();
    List<string> lstRows = new List<string>();
    ISheet objWorksheet;
    string strPath = @"c:\temp\NPOI_Test.XLSX";

    // Use FileStream to open the Excel file
    using (var fStream = new FileStream(strPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
    {
        fStream.Position = 0;
        XSSFWorkbook objWorkbook = new XSSFWorkbook(fStream);
        objWorksheet = objWorkbook.GetSheetAt(0);
        IRow objHeader = objWorksheet.GetRow(0);
        int countCells = objHeader.LastCellNum;

        // Add columns to the DataTable based on the header row of Excel
        for (int j = 0; j < countCells; j++)
        {
            ICell objCell = objHeader.GetCell(j);
            if (objCell == null || string.IsNullOrWhiteSpace(objCell.ToString())) continue;
            {
                dtTable.Columns.Add(objCell.ToString());
            }
        }

        // Add rows to the DataTable, looping through each row and cell
        for (int i = (objWorksheet.FirstRowNum + 1); i <= objWorksheet.LastRowNum; i++)
        {
            IRow objRow = objWorksheet.GetRow(i);
            if (objRow == null || objRow.Cells.All(d => d.CellType == CellType.Blank)) continue;

            for (int j = objRow.FirstCellNum; j < countCells; j++)
            {
                ICell cell = objRow.GetCell(j);
                if (cell != null && !string.IsNullOrEmpty(cell.ToString()) && !string.IsNullOrWhiteSpace(cell.ToString()))
                {
                    lstRows.Add(cell.ToString());
                }
            }

            if (lstRows.Count > 0)
                dtTable.Rows.Add(lstRows.ToArray());

            lstRows.Clear();
        }
    }

    // Assuming dataGridView1 is a DataGridView control on a Form
    dataGridView1.DataSource = dtTable;
}

private void button1_Click(object sender, EventArgs e)
{
    ReadExcelNPOI();
}

public void ReadExcelNPOI()
{
    DataTable dtTable = new DataTable();
    List<string> lstRows = new List<string>();
    ISheet objWorksheet;
    string strPath = @"c:\temp\NPOI_Test.XLSX";

    // Use FileStream to open the Excel file
    using (var fStream = new FileStream(strPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
    {
        fStream.Position = 0;
        XSSFWorkbook objWorkbook = new XSSFWorkbook(fStream);
        objWorksheet = objWorkbook.GetSheetAt(0);
        IRow objHeader = objWorksheet.GetRow(0);
        int countCells = objHeader.LastCellNum;

        // Add columns to the DataTable based on the header row of Excel
        for (int j = 0; j < countCells; j++)
        {
            ICell objCell = objHeader.GetCell(j);
            if (objCell == null || string.IsNullOrWhiteSpace(objCell.ToString())) continue;
            {
                dtTable.Columns.Add(objCell.ToString());
            }
        }

        // Add rows to the DataTable, looping through each row and cell
        for (int i = (objWorksheet.FirstRowNum + 1); i <= objWorksheet.LastRowNum; i++)
        {
            IRow objRow = objWorksheet.GetRow(i);
            if (objRow == null || objRow.Cells.All(d => d.CellType == CellType.Blank)) continue;

            for (int j = objRow.FirstCellNum; j < countCells; j++)
            {
                ICell cell = objRow.GetCell(j);
                if (cell != null && !string.IsNullOrEmpty(cell.ToString()) && !string.IsNullOrWhiteSpace(cell.ToString()))
                {
                    lstRows.Add(cell.ToString());
                }
            }

            if (lstRows.Count > 0)
                dtTable.Rows.Add(lstRows.ToArray());

            lstRows.Clear();
        }
    }

    // Assuming dataGridView1 is a DataGridView control on a Form
    dataGridView1.DataSource = dtTable;
}

private void button1_Click(object sender, EventArgs e)
{
    ReadExcelNPOI();
}

Reading an Excel file with IronXL

The following code demonstrates how to read an Excel file and display it inside a data grid view with IronXL. For more IronXL code examples, see the documentation. Add the following code and include the namespace:

using IronXL;
using System.Data;

using IronXL;
using System.Data;

Notice the inclusion of IronXL. This is necessary for IronXL to work. Add the next few lines:

private void button2_Click(object sender, EventArgs e)
{
    // Load the Excel workbook
    string strPath = @"c:\temp\NPOI_Test.XLSX";
    WorkBook workbook = WorkBook.Load(strPath);

    // Access the default worksheet
    WorkSheet sheet = workbook.DefaultWorkSheet;

    // Convert the worksheet to a DataTable
    var dtTable = sheet.ToDataTable(true);

    // Assuming dataGridView1 is a DataGridView control on a Form
    dataGridView1.DataSource = dtTable;
}

private void button2_Click(object sender, EventArgs e)
{
    // Load the Excel workbook
    string strPath = @"c:\temp\NPOI_Test.XLSX";
    WorkBook workbook = WorkBook.Load(strPath);

    // Access the default worksheet
    WorkSheet sheet = workbook.DefaultWorkSheet;

    // Convert the worksheet to a DataTable
    var dtTable = sheet.ToDataTable(true);

    // Assuming dataGridView1 is a DataGridView control on a Form
    dataGridView1.DataSource = dtTable;
}

As you can see, IronXL reduces the read-and-display operation to roughly 5 lines of code compared to NPOI's 40+, eliminating the manual row iteration and cell-by-cell extraction loop entirely. Browse the full set of IronXL feature guides for more streamlined approaches to common Excel tasks.