uploading and reading from an excel file in asp.net core 2

Question

previously Asp.Net MVC had this third party library which easily allowed uploading and reading from an excel file called Excel Data Reader. We didn't need to have the file on the local disk, which was great because my application needs to run on Azure.

However we are now porting this functionality to asp.net core 2, and it seems from searching that this is not possible. Does anybody know any libraries that would allow me to do this? Please note, I am not looking for solutions that read from a disk. I want to upload an excel file and read data from the stream directly.

Answer 1

I tried this code below (without using libs) for ASP.NET Core and it worked:

public ActionResult OnPostUpload(List<IFormFile> files)
    {
        try
        {
            var file = files.FirstOrDefault();
            var inputstream = file.OpenReadStream();

            XSSFWorkbook workbook = new XSSFWorkbook(stream);

            var FIRST_ROW_NUMBER = {{firstRowWithValue}};

            ISheet sheet = workbook.GetSheetAt(0);
            // Example: var firstCellRow = (int)sheet.GetRow(0).GetCell(0).NumericCellValue;

            for (int rowIdx = 2; rowIdx <= sheet.LastRowNum; rowIdx++)
               {
                  IRow currentRow = sheet.GetRow(rowIdx);

                  if (currentRow == null || currentRow.Cells == null || currentRow.Cells.Count() < FIRST_ROW_NUMBER) break;

                  var df = new DataFormatter();                

                  for (int cellNumber = {{firstCellWithValue}}; cellNumber < {{lastCellWithValue}}; cellNumber++)
                      {
                         //business logic & saving data to DB                        
                      }               
                }
        }
        catch(Exception ex)
        {
            throw new FileFormatException($"Error on file processing - {ex.Message}");
        }
    }