Using EPPlus how can I generate a spreadsheet where numbers are numbers not text

Question

I am creating a spreadsheet from a List using LoadFromArrays

The first entry of the array is a title, the other entries are

Answer 1

Since you are using objects arrays they can contain numbers and strings that look like numbers you will have to go through each object and determine its type:

[TestMethod]
public void Object_Type_Write_Test()
{
    //http://stackoverflow.com/questions/31537981/using-epplus-how-can-i-generate-a-spreadsheet-where-numbers-are-numbers-not-text
    var existingFile = new FileInfo(@"c:\temp\temp.xlsx");
    if (existingFile.Exists)
        existingFile.Delete();

    //Some data
    var list = new List
    {
        new object[]
        {
            "111.11",
            111.11,
            DateTime.Now
        }
    };

    using (var package = new ExcelPackage(existingFile))
    {
        var ws = package.Workbook.Worksheets.Add("Sheet1");
        ws.Cells[1, 1, 2, 2].Style.Numberformat.Format = "0";
        ws.Cells[1, 3, 2, 3].Style.Numberformat.Format = "[$-F400]h:mm:ss\\ AM/PM";

        //This will cause numbers in string to be stored as string in excel regardless of cell format
        ws.Cells["A1"].LoadFromArrays(list);

        //Have to go through the objects to deal with numbers as strings
        for (var i = 0; i < list.Count; i++)
        {
            for (var j = 0; j < list[i].Count(); j++)
            {

                if (list[i][j] is string)
                    ws.Cells[i + 2, j + 1].Value = Double.Parse((string) list[i][j]);
                else if (list[i][j] is double)
                    ws.Cells[i + 2, j + 1].Value = (double)list[i][j];
                else
                    ws.Cells[i + 2, j + 1].Value = list[i][j];

            }
        }

        package.Save();
    }
}

With the above, you see the image below as the output Note the upper left corner cell with the green arrow because it was a string that was written by LoadFromArray which looks like a number: