Reading an excel using the Microsoft.ACE.OLEDB driver.

ReadExcel.cs

var fileName = "file.xlsx";
var connectionString = String.Format(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=""Excel 8.0;HDR=YES;IMEX=1;""", fileName);
var query = "select * from [{0}$]";

using (var dataAdapter = new OleDbDataAdapter(string.Format(query, "worksheet name"), connectionString))
{
    var dataSet = new DataSet();
    dataAdapter.Fill(dataSet);

    var myTable = dataSet.Tables[0];

    foreach (DataRow dataRow in myTable.Rows)
    {
    }
}