EPPlus/FormulaParsing/Excel/Functions/DateTime/Edate.cs

using System.Collections.Generic;
using OfficeOpenXml.FormulaParsing.ExpressionGraph;

namespace OfficeOpenXml.FormulaParsing.Excel.Functions.DateTime;

public class Edate : ExcelFunction {
  public override CompileResult Execute(
      IEnumerable<FunctionArgument> arguments,
      ParsingContext context) {
    ValidateArguments(arguments, 2, eErrorType.Value);
    var dateSerial = ArgToDecimal(arguments, 0);
    var date = System.DateTime.FromOADate(dateSerial);
    var nMonthsToAdd = ArgToInt(arguments, 1);
    var resultDate = date.AddMonths(nMonthsToAdd);
    return CreateResult(resultDate.ToOADate(), DataType.Date);
  }
}