Question

我需要创建一个Event的继承性作为一个SwimmingEvent但是我收到的错误是构造函数不包含0个参数，问题是我不知道哪些参数是要传递的。任何帮助将不胜感激。

//Base Class
class Event
 {
    private string m_evName;
    private string m_evDate;
    private string m_evTime;
    private string m_evFee;
    private string m_evVenue;

    private List<Athlete> m_athletes;


    public String EvName { get { return m_evName; } }
    public String EvDate { get { return m_evDate; } }
    public String EvTime { get { return m_evTime; } }
    public String EvFee { get { return m_evFee; } }
    public String Venue { get { return m_evVenue; } }


    //Getters/Setters - Making private variables avilable in public space through class method
    public Event(String EvName, String EvDate, String EvTime, String EvFee, String EvVenue)
    {
        m_evName = EvName;
        m_evDate = EvDate;
        m_evTime = EvTime;
        m_evFee = EvFee;
        m_evVenue = EvVenue;

        m_athletes = new List<Athlete>();
    }
 } 


   //child class
  class SwimmingEvent : Event
   {
    private String m_distance;
    private String m_inOutVar;

    public SwimmingEvent(String Distance, String InOrOut)
    {
        m_distance = Distance;
        m_inOutVar = InOrOut;
    }


}

Answer 1

由于SwimmingEvent 是 Event，您需要将传递给Event的构造函数的所有参数传递给{{1}的构造函数，然后一些：

SwimmingEvent

Answer 2

using System;
public class MyBase
{
   int num;

   public MyBase(int i )
   {
      num = i;
      Console.WriteLine("in MyBase(int i)");
   }

   public int GetNum()
   {
      return num;
   }
}

public class MyDerived: MyBase
{

    // This constructor will call MyBase.MyBase(int i)
    ***//You are missing this.***
   public MyDerived(int i) : base(i)
   {
   }

}

Answer 3

您需要将所有参数传递回您的父级。

  class SwimmingEvent : Event
   {
    private String m_distance;
    private String m_inOutVar;

    public SwimmingEvent(String Distance, String InOrOut, string evName) : base (evName,"b","c", "d", "e")
    {
        m_distance = Distance;
        m_inOutVar = InOrOut;
    }
}

Answer 4

可能是这样的：

public class Event
{
    public Event() {} // public empty ctor 
    ....
    ....
}

和派生

public class SwimmingEvent  : Event
{
}

通过这种方式，您将避免（假设这是您想要的）编译时错误，因为具有空参数列表的ctor已存在于基类中。

如果这不是您要搜索的内容，请澄清。

Answer 5

在C＃中，在调用派生类（如SwimmingEvent构造函数）的构造函数之前，必须调用基类（Event类）的构造函数。调用基类的构造函数的参数通常使用＆＃34; base ＆＃34;来指定。像这样的关键字：

class SwimmingEvent : Event
{
    ....
    public SwimmingEvent(String Distance, String InOrOut)
        :base(/*Arguments for base class constructor*/)
    {
        //Constructor of derived class
    }
}

如果省略＆＃34;：base（...）＆＃34;，编译器假定调用基类的无参数构造函数，例如，如果你编写＆＃34;：base（）＆＃34;。但是基类中没有无参数构造函数，因此您会收到错误。

您必须在Event类中创建无参数构造函数，或者添加＆＃34; base＆＃34;关键字并指定用于在SwimmingEvent声明中调用现有Event类的构造函数的参数。

基本继承错误，哪个参数？

5 个答案: