Thanks for your posting and considering Aspose.Cells for .NET.
Please use the ExportDataTableAsString method instead of ExportDataTable.
Please see the following sample code.
a Workbook object
Workbook workbook = new Workbook();
file stream containing the Excel file to be opened
FileStream fstream = new FileStream("C:\\book1.xls", FileMode.Open);
Excel file through the file stream
the first worksheet in the Excel file
Worksheet worksheet =
the contents of 7 rows and 2 columns starting from 1st cell to
DataTable dataTable =
worksheet.Cells.ExportDataTableAsString(0, 0, 7, 2, true);
DataTable with DataGrid
file stream to free all resources