Import Excel data into F#

I would like to import some basic data (only few integers) from an Excel file into a F# list. Here is the code I compute which open an Excel file, take the value of the Cell "C6" and 'store' it in a variable called l. However it does not compiled as an type e开发者_如何学Pythonrror appeared. Indeed type of first value is obj. How can I convert it into int?

//#r "Microsoft.Office.Interop.Excel"

//#r "office"

open Microsoft.Office.Interop


let xlApp = new Excel.ApplicationClass()

let xlWorkBook = xlApp.Workbooks.Open(@"C:\Users\Fabien C\Desktop\algo données.xlsx")

let xlWorkSheet = xlWorkBook.Worksheets.["Produits"] :?> Excel.Worksheet

let firstValue = xlWorkSheet.Cells.[6,3]

let (l : int) = firstValue

---

I think just add

:?> int

to the end of the last line to downcast firstValue, but see also the linked duplicate question for more on Excel interop.

---

What is the real type of firstValue? If it's an int, use a dynamic cast:

firstValue :?> int

Otherwise maybe converting to a string and then an int would work:

firstValue |> string |> int