var book = new Book();
var visibleRows = 0;
var invisibleRows = 0;
foreach (var sheet in book.EnumerateSheets(@"c:\path\blah.xlsx")) // or .csv
{
    Console.WriteLine(sheet + " (visible:" + sheet.IsVisible + ")");
    foreach (var row in sheet.EnumerateRows())
    {
        if (!row.IsVisible)
        {
            invisibleRows++;
            continue;
        }
        
        visibleRows++;
        Console.WriteLine(string.Join("\t", row.EnumerateCells()));
    }
}
Console.WriteLine("Visible rows:" + visibleRows);
Console.WriteLine("Invisible rows:" + invisibleRows);