C# NPOI cannot assign FileInputStream variable to XSSFWorkbook variable

Question

So I'm using C# with the NPOI package and trying to assign my file to to a XSSF workbook variable to be read and I'm getting the following error

here is the relevant code fragment

private static XSSFWorkbook workbook;

        //  runs the console, which runs the gogo()
        public static void main(String[] args)
        {
            Console.run2();   
        }

        public void gogo()
        {

            FileInputStream excelFile;
            try
            {
                //  get the file and assign it to excelFile
                excelFile = new FileInputStream(new File(FileName.getFile()));

                //  open up the excelfile workbook
                workbook = new XSSFWorkbook(excelFile);

                //  get the # of sheets in the workbook for iterator
                this.lastSheet = workbook.getNumberOfSheets();

Answer 1

XSSFWorkbook ctor accepts Stream as its argument. However, FileInputStream does not extend Stream (nor is it implicitly convertible). One way to solve your issue is to use FileStream instead of FileInputStream. For example:

FileStream excelFile = File.OpenRead(FileName.getFile());