invoke formula in excel via epplus

Question

I have an excel sheet in ASP.NET MVC4 C# project and I am able to read from excel sheet successfully using EPPlus. Now, I want to be able to pass in 2 numbers into cell C:2 and C:3 and be able to invoke formula in C:4 which is =SUM(C2:C3).

So from C# I want to pass in 4 and 6 and invoke the formula and be able to get the result back from C:4 which is 40 (SUM of 10 and 30). How do I accomplish that in C#.

In the following code, I get back zero for d.Average

d.Average = Convert.ToDouble(currentWorksheet.Cells["C4"].Value);

Here is my following code in c# so far to traverse a row.

        using (var package = new ExcelPackage(existingFile))
        {
            ExcelWorkbook workBook = package.Workbook;
            var currentWorksheet = workBook.Worksheets.First();
            currentWorksheet.Workbook.CalcMode = ExcelCalcMode.Automatic;
            currentWorksheet.Cells["C4"].Formula = "=SUM(C2:C3)";
            currentWorksheet.Cells["C2"].Value = 10;
            currentWorksheet.Cells["C3"].Value = 30;
            package.Save();


        }

        using (var package = new ExcelPackage(existingFile))
        {
            ExcelWorkbook workBook = package.Workbook;
            var currentWorksheet = workBook.Worksheets.First();
            d.Average = Convert.ToDouble(currentWorksheet.Cells["C4"].Value);
        }

Answer 1

Skip the = in the formula string.

Replace currentWorksheet.Cells["C4"].Formula = "=SUM(C2:C3)";

with

currentWorksheet.Cells["C4"].Formula = "SUM(C2:C3)";