c# - 一个简单的策略模式示例的问题

Question

错误是:

FirstPattern.Character.Character' does not contain a constructor that takes 0 arguments

代码如下:

public interface WeaponBehavior
{
    void UseWeapon();
}

class SwordBehavior : WeaponBehavior
{
    public void UseWeapon()
    {
        Console.WriteLine("A sword as plain as your wife.");
    }
}

然后，我有一个字符类:

public abstract class Character
{
    WeaponBehavior weapon;

    public Character(WeaponBehavior wb)
    {
        weapon = wb;
    }

    public void SetWeapon(WeaponBehavior wb)
    {
        weapon = wb;
    }

    public abstract void Fight();
}



public class Queen : Character
{        
    public Queen(WeaponBehavior wb)
    {
        SetWeapon(wb);
    }

    public override void Fight()
    {

    }
}

我不确定我应该如何处理字符类和子类。你们能把我推向正确的方向吗？

Answer 1

由于 Queen 派生自 Character 而 Character 只有一个带有 WeaponBehavior 参数的构造函数，您需要在 Queen 构造函数中显式调用基本构造函数 - 这意味着对 SetWeapon 的调用也是不必要的:

public Queen(WeaponBehavior wb) : base(wb)
{
}

或者，您可以在 Character 中提供默认构造函数，并保持原始代码不变:

public abstract class Character
{
   WeaponBehavior weapon;

   public Character() { }
   ...