Excel OLEDB Import Restriction

public string GetConnectionString(string FileNamePath, bool HasHeader)
        {
            string ConnectionString = "";
            string Extension = Path.GetExtension(FileNamePath).ToLower();

            string BinaryExcelProvider = "Microsoft.Jet.OLEDB.4.0";
            string XmlExcelProvider = "Microsoft.ACE.OLEDB.12.0";
            string BinaryExcelExtProperties = "Excel 8.0";
            string XmlExcelExtProperties = "Excel 12.0";
            string XmlMacroExcelExtProperties = "EXCEL 12.0 Macro";

            string Provider = "";
            string ExtendedProperties = "";

            switch (Extension)
            {
                case ".xls":
                    Provider = BinaryExcelProvider;
                    ExtendedProperties = BinaryExcelExtProperties;
                    break;

                case ".xlsx":
                    Provider = XmlExcelProvider;
                    ExtendedProperties = XmlExcelExtProperties;
                    break;

                case ".xlsm":
                    Provider = XmlExcelProvider;
                    ExtendedProperties = XmlMacroExcelExtProperties;
                    break;
            }

            string Header = ";HDR=NO;IMEX=1";
            if (HasHeader)
                Header = ";HDR=YES;IMEX=1";
            string ConnectionStringFormat = "Provider={0};Data Source={1};Extended Properties=\"{2}{3}\";";

            ConnectionString = string.Format(ConnectionStringFormat, Provider, FileNamePath, ExtendedProperties, Header);
            return ConnectionString;
        }

public DataSet ReadWorkSheet(string excelFile)
        {
            Success = false;
            System.Data.DataSet excelDataSet = new DataSet();
            string connectionString = this.GetConnectionString(excelFile);


            using (OleDbConnection objConn = new System.Data.OleDb.OleDbConnection(connectionString))
            {
                try
                {
                    objConn.Open();
                    OleDbDataAdapter cmd = new OleDbDataAdapter("select * from [Sheet1$A1:E10]" , objConn);
                    cmd.Fill(excelDataSet, "MyData");
                    cmd.Dispose();
                }
                catch { }
                finally
                {
                    if (objConn != null)
                    {
                        objConn.Close();
                        objConn.Dispose();
                    }

                }
            }
 return excelDataset
}