Change your Excel sheet into CSV file and try this:
FileUpload1.SaveAs(Server.MapPath("~/tmpdir/") + FileUpload1.FileName);
System.IO.StreamReader myFile = new System.IO.StreamReader(Server.MapPath("~/tmpdir/") + FileUpload1.FileName);
string myString = myFile.ReadToEnd();
myFile.Close();
string[] lines = myString.Split(new string[] { Environment.NewLine }, StringSplitOptions.None);
foreach (string line in lines)
{
if (line != "")
{
string[] columns = line.Split(',');
}
else
{
}
}