C# - 错误 CS0029 无法将类型“int”隐式转换为“Core.Models.Mandate”

Question

I have this model in my ASP.NET Core Web API:

Models:

namespace Core.Models
{
  public class Mandate : EntityBase
  {
    public DateTime StartDate { get; set; }
    public DateTime EndDate { get; set; }
    public int? PaymentFrequency { get; set; }  //1=Monthly, 2=Quarterly, 3=Yearly
    public int? PaymentCount { get; set; }
    public decimal Amount { get; set; }
  }
}

ViewModel:

public class MandateVM
{
    public DateTime StartDate { get; set; }
    public DateTime EndDate { get; set; }
    public int? PaymentFrequency { get; set; }  //1=Monthly, 2=Quarterly, 3=Yearly
    public decimal Amount { get; set; }
}

I have written some helpers that gets T otalMonth , TotalQuarter and TotalYear from StartDate and EndDate as show below:

namespace Infrastructure.Helpers
{
  public static class ConstantHelper
  {
    private static IConfiguration Configuration { get; set; }

    public static int GetTotalMonth(DateTime startDate, DateTime endDate)
    {
        int totalMonth = 12 * (startDate.Year - endDate.Year) + startDate.Month - endDate.Month;
        return Convert.ToInt32(Math.Abs(totalMonth));
    }

    public static int GetTotalQuarter(DateTime startDate, DateTime endDate)
    {
        int firstQuarter = getQuarter(startDate);
        int secondQuarter = getQuarter(endDate);
        return 1 + Math.Abs(firstQuarter - secondQuarter);
    }

    private static int getQuarter(DateTime date)
    {
        return (date.Year * 4) + ((date.Month - 1) / 3);
    }

    public static int GetTotalYear(DateTime startDate, DateTime endDate)
    {
        int years = endDate.Year - startDate.Year;

        if (startDate.Month == endDate.Month &&// if the start month and the end month are the same
            endDate.Day < startDate.Day)// BUT the end day is less than the start day
        {
            years--;
        }
        else if (endDate.Month < startDate.Month)// if the end month is less than the start month
        {
            years--;
        }
        return Math.Abs(years);
    }
  }
}

EntityMapper:

    public Mandate FromMandateCreateDtoToMandate(MandateVM mandateCreateVM)
    {
        if (mandateCreateVM == null)
        {
            return null;
        }

        Mandate mandate = new Mandate()
        {
            StartDate = mandateCreateVM.StartDate,
            EndDate = mandateCreateVM.EndDate,
            DueDate = mandateCreateVM.DueDate,
            PaymentFrequency = mandateCreateVM.PaymentFrequency, //1=Monthly, 2=Quarterly, 3=Yearly
            Amount = mandateCreateVM.Amount,
        };
        int numberOfTimes;
        switch (mandateCreateVM.PaymentFrequency)
        {
            case 1:
                return numberOfTimes = ConstantHelper.GetTotalMonth(mandate.StartDate, mandate.EndDate);
                break;
            case 2:
                return numberOfTimes = ConstantHelper.GetTotalQuarter(mandate.StartDate, mandate.EndDate);
                break;
            default:
                return numberOfTimes = ConstantHelper.GetTotalYear(mandate.StartDate, mandate.EndDate);
                break;
        }
        mandate.PaymentCount = numberOfTimes;
        return mandate;         
    }

PaymentFrequency determines number of times (numberOfTimes) payment will be made.

1 = Monthly

2 = Quarterly

3 = Yearly

I expected it to return numberOfTimes as int, but I got this error:

Error CS0029 Cannot implicitly convert type 'int' to 'Core.Models.Mandate'

It highlights:

return numberOfTimes = ConstantHelper.GetTotalMonth(mandate.StartDate, mandate.EndDate);

return numberOfTimes = ConstantHelper.GetTotalQuarter(mandate.StartDate, mandate.EndDate);

return numberOfTimes = ConstantHelper.GetTotalYear(mandate.StartDate, mandate.EndDate);

How do I get this resolved?

Thanks

Answer 1

Just delete the return in every cases of your switch case in FromMandateCreateDtoToMandate() .

Those return will try to exit the function and return numberOfTimes ( int ) instead of, I presume, as you wanted only exit the switch case