ExcelML Writer translates any DataTable or DataSet object into an Excel- readable workbook.
It can apply styling to header rows as defined in the configuration file (see attached "Test" project). Multiple DataTables are processed into multiple worksheets and the data is output into columns, as it would look in a database table. The information can then be manipulated as any other Excel spreadsheet.
ExML Writer is FREE and open-source and is available on GitHub.
ExML Writer is published under the Apache License 2.0 and is free to use in personal and professional projects. Feel free to download and use or even contribute back.