Nov 12, 2019 · There’s often a scenario in .NET application development where you need to read data from an Excel file, or produce one. Quite a few libraries are available, but there’s one that shines: NPOI. It’s a C# port of the POI Java project by Apache, and contrary to some of its competitors, it’s free, it’s open source, and it’s a stand-alone implementation, that is, no interop. …