Reading Excel files

We can read and write to Microsoft Excel files using the Open XML SDK. It provides the tools for us to work with not only Excel files but also Word and PowerPoint files. To use the Open XML SDK, we need to add the DocumentFormat.OpenXml NuGet package to our project.

Modern Excel files with the XLSX file extension are made up of a compressed collection of XML files. To view the individual files, change the file extension from XLSX to ZIP and view the files using a .zip viewer. You can also extract the files.

When using the Open XML SDK, the Excel document is represented with the SpreadsheetDocument class. This is the hierarchy of the elements in the class:

• workbook – the root element of the document
• sheets – the container for the sheets
• sheet – the pointer to the sheet definition file
• worksheet – the sheet definition that contains the sheet data
• sheetData – the data
• row –...