La biblioteca XLSX de C#

using IronXL;
using System.IO;

// Import any XLSX, XLS, XLSM, XLTX, CSV and TSV
WorkBook workBook = WorkBook.Load("sample.xlsx");

// Export the excel file as XLS, XLSX, XLSM, CSV, TSV, JSON, XML
workBook.SaveAs("sample.xls");
workBook.SaveAs("sample.xlsx");
workBook.SaveAs("sample.tsv");
workBook.SaveAsCsv("sample.csv");
workBook.SaveAsJson("sample.json");
workBook.SaveAsXml("sample.xml");

// Export the excel file as Html, Html string
workBook.ExportToHtml("sample.html");
string htmlString = workBook.ExportToHtmlString();

// Export the excel file as Binary, Byte array, Data set, Stream
byte[] binary = workBook.ToBinary();
byte[] byteArray = workBook.ToByteArray();
System.Data.DataSet dataSet = workBook.ToDataSet(); // Allow easy integration with DataGrids, SQL and EF
Stream stream = workBook.ToStream();

Imports IronXL
Imports System.IO

' Import any XLSX, XLS, XLSM, XLTX, CSV and TSV
Private workBook As WorkBook = WorkBook.Load("sample.xlsx")

' Export the excel file as XLS, XLSX, XLSM, CSV, TSV, JSON, XML
workBook.SaveAs("sample.xls")
workBook.SaveAs("sample.xlsx")
workBook.SaveAs("sample.tsv")
workBook.SaveAsCsv("sample.csv")
workBook.SaveAsJson("sample.json")
workBook.SaveAsXml("sample.xml")

' Export the excel file as Html, Html string
workBook.ExportToHtml("sample.html")
Dim htmlString As String = workBook.ExportToHtmlString()

' Export the excel file as Binary, Byte array, Data set, Stream
Dim binary() As Byte = workBook.ToBinary()
Dim byteArray() As Byte = workBook.ToByteArray()
Dim dataSet As System.Data.DataSet = workBook.ToDataSet() ' Allow easy integration with DataGrids, SQL and EF
Dim stream As Stream = workBook.ToStream()

using IronXL;
using System;
using System.Linq;

// Supported for XLSX, XLS, XLSM, XLTX, CSV and TSV
WorkBook workBook = WorkBook.Load("sample.xlsx");

// Select worksheet at index 0
WorkSheet workSheet = workBook.WorkSheets[0];

// Get any existing worksheet
WorkSheet firstSheet = workBook.DefaultWorkSheet;

// Select a cell and return the converted value
int cellValue = workSheet["A2"].IntValue;

// Read from ranges of cells elegantly.
foreach (var cell in workSheet["A2:A10"])
{
    Console.WriteLine("Cell {0} has value '{1}'", cell.AddressString, cell.Text);
}

// Calculate aggregate values such as Min, Max and Sum
decimal sum = workSheet["A2:A10"].Sum();

// Linq compatible
decimal max = workSheet["A2:A10"].Max(c => c.DecimalValue);

Imports IronXL
Imports System
Imports System.Linq

' Supported for XLSX, XLS, XLSM, XLTX, CSV and TSV
Private workBook As WorkBook = WorkBook.Load("sample.xlsx")

' Select worksheet at index 0
Private workSheet As WorkSheet = workBook.WorkSheets(0)

' Get any existing worksheet
Private firstSheet As WorkSheet = workBook.DefaultWorkSheet

' Select a cell and return the converted value
Private cellValue As Integer = workSheet("A2").IntValue

' Read from ranges of cells elegantly.
For Each cell In workSheet("A2:A10")
	Console.WriteLine("Cell {0} has value '{1}'", cell.AddressString, cell.Text)
Next cell

' Calculate aggregate values such as Min, Max and Sum
Dim sum As Decimal = workSheet("A2:A10").Sum()

' Linq compatible
Dim max As Decimal = workSheet("A2:A10").Max(Function(c) c.DecimalValue)

using IronXL;

// Create new Excel spreadsheet
WorkBook workBook = WorkBook.Create(ExcelFileFormat.XLSX);

// Create worksheets (workSheet1, workSheet2, workSheet3)
WorkSheet workSheet1 = workBook.CreateWorkSheet("workSheet1");
WorkSheet workSheet2 = workBook.CreateWorkSheet("workSheet2");
WorkSheet workSheet3 = workBook.CreateWorkSheet("workSheet3");

// Set worksheet position (workSheet2, workSheet1, workSheet3)
workBook.SetSheetPosition("workSheet2", 0);

// Set active for workSheet3
workBook.SetActiveTab(2);

// Remove workSheet1
workBook.RemoveWorkSheet(1);

workBook.SaveAs("manageWorkSheet.xlsx");

Imports IronXL

' Create new Excel spreadsheet
Private workBook As WorkBook = WorkBook.Create(ExcelFileFormat.XLSX)

' Create worksheets (workSheet1, workSheet2, workSheet3)
Private workSheet1 As WorkSheet = workBook.CreateWorkSheet("workSheet1")
Private workSheet2 As WorkSheet = workBook.CreateWorkSheet("workSheet2")
Private workSheet3 As WorkSheet = workBook.CreateWorkSheet("workSheet3")

' Set worksheet position (workSheet2, workSheet1, workSheet3)
workBook.SetSheetPosition("workSheet2", 0)

' Set active for workSheet3
workBook.SetActiveTab(2)

' Remove workSheet1
workBook.RemoveWorkSheet(1)

workBook.SaveAs("manageWorkSheet.xlsx")

using IronXL;

// Create new Excel WorkBook document
WorkBook workBook = WorkBook.Create();

// Convert XLSX to XLS
WorkBook xlsWorkBook = WorkBook.Create(ExcelFileFormat.XLS);

// Create a blank WorkSheet
WorkSheet workSheet = workBook.CreateWorkSheet("new_sheet");

// Add data and styles to the new worksheet
workSheet["A1"].Value = "Hello World";
workSheet["A1"].Style.WrapText = true;
workSheet["A2"].BoolValue = true;
workSheet["A2"].Style.BottomBorder.Type = IronXL.Styles.BorderType.Double;

// Save the excel file as XLS, XLSX, CSV, TSV, JSON, XML, HTML and streams
workBook.SaveAs("sample.xlsx");

Imports IronXL

' Create new Excel WorkBook document
Private workBook As WorkBook = WorkBook.Create()

' Convert XLSX to XLS
Private xlsWorkBook As WorkBook = WorkBook.Create(ExcelFileFormat.XLS)

' Create a blank WorkSheet
Private workSheet As WorkSheet = workBook.CreateWorkSheet("new_sheet")

' Add data and styles to the new worksheet
Private workSheet("A1").Value = "Hello World"
Private workSheet("A1").Style.WrapText = True
Private workSheet("A2").BoolValue = True
Private workSheet("A2").Style.BottomBorder.Type = IronXL.Styles.BorderType.Double

' Save the excel file as XLS, XLSX, CSV, TSV, JSON, XML, HTML and streams
workBook.SaveAs("sample.xlsx")

using IronXL;
using System;
using System.Data;

// Supported for XLSX, XLS, XLSM, XLTX, CSV and TSV
WorkBook workBook = WorkBook.Load("sample.xlsx");

// Convert the whole Excel WorkBook to a DataSet
DataSet dataSet = workBook.ToDataSet();

foreach (DataTable table in dataSet.Tables)
{
    Console.WriteLine(table.TableName);

    // Enumerate by rows or columns first at your preference
    foreach (DataRow row in table.Rows)
    {
        for (int i = 0 ; i < table.Columns.Count ; i++)
        {
            Console.Write(row[i]);
        }
    }
}

Imports IronXL
Imports System
Imports System.Data

' Supported for XLSX, XLS, XLSM, XLTX, CSV and TSV
Private workBook As WorkBook = WorkBook.Load("sample.xlsx")

' Convert the whole Excel WorkBook to a DataSet
Private dataSet As DataSet = workBook.ToDataSet()

For Each table As DataTable In dataSet.Tables
	Console.WriteLine(table.TableName)

	' Enumerate by rows or columns first at your preference
	For Each row As DataRow In table.Rows
		For i As Integer = 0 To table.Columns.Count - 1
			Console.Write(row(i))
		Next i
	Next row
Next table

using IronXL;
using System;
using System.Data;

// Supported for XLSX, XLS, XLSM, XLTX, CSV and TSV
WorkBook workBook = WorkBook.Load("sample.xlsx");

// Select default sheet
WorkSheet workSheet = workBook.DefaultWorkSheet;

// Convert the worksheet to DataTable
DataTable dataTable = workSheet.ToDataTable(true);

// Enumerate by rows or columns first at your preference
foreach (DataRow row in dataTable.Rows)
{
    for (int i = 0 ; i < dataTable.Columns.Count ; i++)
    {
        Console.Write(row[i]);
    }
}

Imports IronXL
Imports System
Imports System.Data

' Supported for XLSX, XLS, XLSM, XLTX, CSV and TSV
Private workBook As WorkBook = WorkBook.Load("sample.xlsx")

' Select default sheet
Private workSheet As WorkSheet = workBook.DefaultWorkSheet

' Convert the worksheet to DataTable
Private dataTable As DataTable = workSheet.ToDataTable(True)

' Enumerate by rows or columns first at your preference
For Each row As DataRow In dataTable.Rows
	For i As Integer = 0 To dataTable.Columns.Count - 1
		Console.Write(row(i))
	Next i
Next row