Ответ 1
Простой пример
// Get the file we are going to process
var existingFile = new FileInfo(filePath);
// Open and read the XlSX file.
using (var package = new ExcelPackage(existingFile))
{
// Get the work book in the file
var workBook = package.Workbook;
if (workBook != null)
{
if (workBook.Worksheets.Count > 0)
{
// Get the first worksheet
var currentWorksheet = workBook.Worksheets.First();
// read some data
object col1Header = currentWorksheet.Cells[1, 1].Value;