https://github.com/infsprout/XlsxParser
NOTE: XlsxParser can only read xlsx, xlsm file format.
XlsxParser parses the xlsx file and makes the table you defined in the file a collection of the desired object.
Features 
    - All source code included 
    - Pure C# code
    - Can parse xlsx at runtime 
    - Can parse encrypted xlsx 
    - Can parse a horizontal table 
    - Can parse a table with merged cells 
    - Can import from Excel Online 
    - Can import from Google Sheets 
    - .NET 2.0 Subset Compatibility