Open XML SDK write Double Value to Excel cell

Question

I am transfering values from a SQL Database into an ExcelSheet. I can write Strings and Integers no problem but when I write doubles Excel needs to repair the document. It says the Numbers are formated as text.

i use this code :

double val = Math.Round(reader.GetDouble(3),2);
cell.CellValue= new CellValue(Convert.ToString(val));
cell.DataType = new EnumValue<CellValues>(CellValues.Number);

Answer 1

Please try to use:

cell.CellValue = new CellValue(val.ToString(CultureInfo.InvariantCulture));

instead of:

cell.CellValue= new CellValue(Convert.ToString(val));

Answer 2

Using CultureInfo.InvariantCulture does not cover all cases very large or very small numbers as well as NaN and +-Inf will stil trigger Excel to repair the file. At the moment I am using this as a work around:

 bool isNumeric = IsNumeric(value, out double number);
            if (isNumeric && ! (double.IsNaN(number) | double.IsInfinity(number) | Math.Abs(number) >1e100))
            {
                cell.DataType = CellValues.Number;
                cell.CellValue = new CellValue(String.Format(CultureInfo.InvariantCulture, "{0:0.####################}", number));
            }
            else
            {
                cell.DataType = CellValues.String;
                cell.CellValue = new CellValue(value.ToString());
            }

Is there a better solution to this?