Source Excel document:

using System;
using System.Collections.Generic;
using System.Text;
using Bytescout.XLS;
namespace ExportToHTML
{
class Program
{
static void Main(string[] args)
{
// Open XLSDocument
XLSDocument document = new XLSDocument("SimpleReport.xls");
// Get Worksheet
Worksheet worksheet = document.WorkBook.Worksheets[0];
// Export to HTML
worksheet.SaveAsHTML("SimpleReport.htm");
// Close XLSDocument
document.Close();
}
}
}

Download example source code: bytescoutxls_export_xls_to_html.zip (5 KB)