ExcelFormulaParser.Engine.ExcelUtilities.NumericExpressionEvaluator.OperandAsDouble C# (CSharp) Method

        public double? OperandAsDouble(object op)
        {
            if (op is double || op is int)
            {
                return Convert.ToDouble(op);
            }
            if (op != null)
            {
                double output;
                if (double.TryParse(op.ToString(), out output))
                {
                    return output;
                }
            }
            return null;
        }