OpenXML is a file format introduced with Microsoft Office in 2000 with new file extensions appended x and m at the end like .docx/ .docm, .xlsx/ .xlsm, .pptx/.pptm.
- Then from 2007 office onward this became the default file format.
- This is a zipped file format that has XML files associated with a document and could be explored if you save it as a .zip extension and then unzip it to see the XML files.
To explore the possibilities of this file format with .Net we have separate SDK. Download and install OpenXml SDK 2.0 and then we have to add the references DocumentFormat.OpenXml and WindowsBase assemblies. OpenXml SDK is an open-source and also various utilities are available.
- In some of the applications we have to deal with large content Excel files i.e. to upload/download from UI and the processing time could be reduced by saving it in binary format i.e. with extension .xlsb.
- In binary formatted excel, the size gets reduced to 40-60% for larger content and also get directly opened on double click.
- Various third party programming component like Aspose.cells, Spire.xls are available to do the processing of binary formatted excel with .Ne
Note* OpenXml SDK doesn’t work with binary formatted excel files.