C＃爲什麼接口不能實現這樣的方法？什麼是解決我的問題的解決方法？

Question

爲什麼接口不能實現這樣的方法？

public interface ITargetableUnit { 
     //Returns whether the object of a class that implements this interface is targetable 
    bool unitCanBeTargeted(){ 
     bool targetable = false; 
     if(this is Insect){ 
      targetable = (this as Insect).isFasterThanLight(); 
     } 
     else if(this is FighterJet){ 
      targetable = !(this as FighterJet).Flying; 
     } 
     else if(this is Zombie){ 
      targetable = !(this as Zombie).Invisible; 
     } 
     return targetable; 
    } 
} 

昆蟲，和殭屍都已經從基類派生生物和FighterJet從類機派生然而，並非所有的生物-S是靶向，不使用ITargetableUnit inteface。

有沒有解決我面臨的問題的解決方法？

Answer 1

也許你想要一個抽象類而不是一個接口？

接口定義了類提供的方法。抽象類也可以做到這一點，但也可以爲每個孩子接管一些計算。

請注意，從技術角度來看，Insect也可以是Zombie。

快樂編碼！

public abstract class TargetableUnit 
{ 
    //Returns whether the object of a class that implements this interface is targetable 
    public bool unitCanBeTargeted() 
    { 
     bool targetable = false; 
     if (this is Insect) 
     { 
      targetable = (this as Insect).isFasterThanLight(); 
     } 
     else if (this is FighterJet) 
     { 
      targetable = !(this as FighterJet).Flying; 
     } 
     else if (this is Zombie) 
     { 
      targetable = !(this as Zombie).Invisible; 
     } 

     return targetable; 
    } 
} 

public class Insect : TargetableUnit 
{ 
    public bool isFasterThanLight() 
    { 
     return System.DateTime.UtcNow.Second == 0; 
    } 
} 
public class FighterJet : TargetableUnit 
{ 
    public bool Flying { get; set; } 
} 
public class Zombie : TargetableUnit 
{ 
    public bool Invisible { get; set; } 
} 

Answer 2

就像大家說的，你不能定義接口的行爲。將接口繼承到特定的類。

public interface ITargetableUnit 
{ 

    bool unitCanBeTargeted(); 

} 

public class Insect : ITargetableUnit //you can add other interfaces here 
{ 

    public bool unitCanBeTarget() 
    { 
      return isFasterThanLight(); 
    } 
} 

public class Ghost : ITargetableUnit 
{ 
    public bool unitCanBeTarget() 
    { 
      return !Flying(); 
    } 
} 

public class Zombie : ItargetableUnit 
{ 
    public bool unitCanBeTarget() 
    { 
      return !Invisible(); 
    } 
} 

Answer 3

只是爲了記錄在案，可以真正做到這一點（DONT！），但這個心不是考慮一個很好的做法，使你有存取權限代碼extensionmethods。 Mybirthname's解決方案是要走的路，這只是爲了演示。

public interface ITargetableUnit { } 


public static class ITargetableUnitExtension 
{ 

    public static bool unitCanBeTargeted(this ITargetableUnit unit) 
    { 
     bool targetable = false; 
     Insect insect = unit as Insect; 
     if(insect != null) 
      return insect.isFasterThanLight(); 
     FighterJet jet = unit as FighterJet; 
     if(jet != null) 
      return !jet.Flying; 
     Zombie zombie = unit as Zombie; 
     if(zombie != null) 
      return zombie.Invisible; 
     return false; 
    } 
}