代码之家 › 专栏 › 技术社区 › Haraldur

派生类中枚举的C#极限选项

derived-class enums c#

-2

Haraldur · 技术社区 · 7 年前

所以我试图限制我在基类中声明的枚举的选项,我可以在派生类中选择。

namespace FLYNET.Personeel
{
    public enum Graad
    {
        Captain,
        SeniorFlightOfficer,
        SecondOfficer,
        JuniorFlightOfficer,
        Steward,
        Purser
    };

public abstract class VliegendPersoneelslid : Personeelslid
{
    public VliegendPersoneelslid()
    {
    }

    public override decimal BerekenTotaleKostprijsPerDag()
    {
        return BasisKostprijsPerDag;
    }

    public List<Certificaat> Certificaten { get; set; }
}

上面是我试图从基类员工那里使用的枚举。

namespace FLYNET.Personeel
{
    public class CockpitPersoneel : VliegendPersoneelslid
    {
        public int VliegUren { get; set; }

        public Graad Graad { get; set; }


            public CockpitPersoneel()
            {
                if (Grade = Graad.Steward || Grade = Graad.Purser)
                {
                    throw new Exception 
                }
            }

            public override decimal BerekenTotaleKostprijsPerDag()
            {
                decimal kostprijsPersoneel = 0m;
                decimal percentage;

                return kostprijsPersoneel;
            }
        }
    }

我知道这可能是一个初学者的问题(它是:p),但请容忍我。

2 回复 | 直到 7 年前

Dmitry Bychenko 7 年前

我建议使用

public enum Grade {
   None, // <- zero option is often a good idea to include 
   Captain,
   SeniorFlightOfficer,
   SecondOfficer,
   JuniorFlightOfficer,
   Steward,
   Purser };

public static class GradeExtensions { 
  public static bool IsCabinCrue(this Grade grade) {
    return grade == Grade.Steward || grade == Grade.Purser;
  }

  public static bool IsCockpitPersonnel(this Grade grade) {
    return grade == Grade.Captain || 
           grade == Grade.SeniorFlightOfficer ||
           grade == Grade.SecondOfficer ||
           grade == Grade.JuniorFlightOfficer;
  } 
}

然后,您可以使用扩展方法,就好像它们是枚举的方法一样 正在验证 Grade 提供的值:

public class CabinCrue {
  ...
  public CabinCrue(Grade grade) {
    // Validation: Cabin Crue grade only
    // not Exception but ArgumentException: it's argument grade that's wrong
    if (!grade.IsCabinCrue()) 
      throw new ArgumentException("Cabin crue only", "grade");

    Grade = grade;

    ...
  } 

  public Grade Grade {
    get;
    private set;
  }
  ...
}

Mong Zhu Bart de Boer 7 年前

我认为你在逻辑上有错误。您正在尝试验证 Grade Graad 在构造函数中。财产无法在构造函数调用之前设置。您的验证将检查变量的默认值 Captain ).

你需要通过考试进入构造函数,以便能够进行验证:

public CockpitPersoneel(Graad g)
{
    if (g = Graad.Steward || g = Graad.Purser)
    {
        throw new Exception("wrong choice");
    }
    else
    {
        this.Graad = g;
    }
}

Graad _myGrade;

public Graad GradeOfPerson
{
    get { return _myGrade; }
    set
    {
        if (value = Graad.Steward || value = Graad.Purser)
        {
            throw new Exception("Not Allowed");

        }
        _myGrade = value; 
    }
}

这样,您可以将构造函数留空:

public CockpitPersoneel()
{
}