C＃InvalidCastException獲取派生類型

Question

我在Unity中製作基於2D網格的遊戲，並擁有一個Weapon類，該類具有獲取武器統計信息的屬性。統計數據由武器組成部分計算，部件的數量和類型由武器類型WepGun，WepStaff或WepSword定義。每種武器類型都有親和力和抓地力。爲了讓玩家裝備武器，我必須得到它的實際類型（槍/職員/劍），以便我可以使用武器上的區域。該武器作爲武器存儲在保存數據中（可能是idk問題），並通過Newtonsoft.Json json庫保存到磁盤。

當我嘗試分配Weapon的字段時，沒有問題，但是當我嘗試分配實際武器類型的字段時，我得到InvalidCastException: Cannot cast from source type to destination type.。 我很確定這不是因爲我用他們開始的武器類型創造角色而是下賤的。（this鏈接顯示的作品有點類似於我的情況爲例）

代碼中的問題：

[SaveData.cs]

[JsonProperty] public static CharacterSaveData JESSIE = new CharacterSaveData(...,new StatManager.WepGun()); 

public class CharacterSaveData { 
    ... 

    [JsonProperty] public StatManager.Weapon weapon; 

    internal CharacterSaveData (..., StatManager.Weapon weapon) { 
     this.weapon = weapon; 

     weapon.affinity = StatManager.Part.ART_AFFINITY; 
     ((StatManager.WepGun)weapon).barrel = new StatManager.Part(StatManager.PartType.GUN_BARREL, StatManager.AttackType.CARDINAL_SINGLE_TARGET, 3, 0, 0.2f); //error occurs here 
    } 

[StatManager.cs]

public abstract class Weapon { 
    [JsonProperty] private Part _affinity; 
    public Part affinity {...} 
    [JsonProperty] private Part _grip; 
    public Part grip {...} 

    ...properties 

    internal Weapon (Part affinity, Part grip) { 
     _affinity = affinity; 
     _grip = grip; 
    } 
} 
public class Part { 
    ...predefined parts (ART_AFFINITY is here) 

    public PartType? partType; //enum 
    public AttackType? attackType; //enum 
    public int? attackRange; 
    public int? damageRange; 
    public float? modifier; 
    public ModType? modifierType; //enum 

    public Part (PartType? partType = null, AttackType? attackType = null, int? attackRange = null, int? damageRange = null, float? modifier = null, ModType? modifierType = null) { 
     this.partType = partType; 
     this.attackType = attackType; 
     this.attackRange = attackRange; 
     this.damageRange = damageRange; 
     this.modifier = modifier; 
     this.modifierType = modifierType; 
    } 
} 

public class WepGun : Weapon { 
    [JsonProperty] private Part _barrel; 
    public Part barrel {...} 
    [JsonProperty] private Part _sight; 
    public Part sight {...} 
    [JsonProperty] private Part _bullet; 
    public Part bullet {...} 

    ...properties 

    public WepGun (Part barrel = null, Part grip = null, Part sight = null, Part bullet = null, Part affinity = null) : base(affinity,grip) { 
     _barrel = barrel; 
     _sight = sight; 
     _bullet = bullet; 
    } 
} 
public class WepStaff : Weapon { 
    [JsonProperty] private Part _shaft; 
    public Part shaft {...} 
    [JsonProperty] private Part _head; 
    public Part head {...} 
    [JsonProperty] private Part _accessory; 
    public Part accessory {...} 

    ...properties 

    public WepStaff (Part shaft = null, Part grip = null, Part head = null, Part accessory = null, Part affinity = null) : base(affinity,grip) { 
     _shaft = shaft; 
     _head = head; 
     _accessory = accessory; 
    } 
} 
public class WepSword : Weapon { 
    [JsonProperty] private Part _blade; 
    public Part blade {...} 
    [JsonProperty] private Part _guard; 
    public Part guard {...} 
    [JsonProperty] private Part _accessory; 
    public Part accessory {...} 

    ...properties 

    public WepSword (Part blade = null, Part guard = null, Part grip = null, Part accessory = null, Part affinity = null) : base(affinity,grip) { 
     _blade = blade; 
     _guard = guard; 
     _accessory = accessory; 
    } 
} 

Answer 1

如果這是違規行，請更改並調試它。

((StatManager.WepGun)weapon).barrel = new StatManager.Part(StatManager.PartType.GUN_BARREL, StatManager.AttackType.CARDINAL_SINGLE_TARGET, 3, 0, 0.2f); 

變化

var wepGun = weapon as StatManager.WepGun; 
if(null != wepGun) 
    wepGun.barrel = new StatManager.Part(StatManager.PartType.GUN_BARREL, StatManager.AttackType.CARDINAL_SINGLE_TARGET, 3, 0, 0.2f); 
else 
{ 
    // debug code 
} 

PS我認爲你應該使用的接口，而不是類武器類型。有一天你會想要將兩種武器類型合併爲一種。你不能用類來做到這一點。