Enum.HasFlag 未按预期工作

Question

我有一个带有这样标志的枚举：

[Flags]
public enum ItemType
{
    Shop,
    Farm,
    Weapon,
    Process,
    Sale
}

然后我在列表中有几个对象，其中一些设置了标志，一些标志未设置。它看起来像这样：

public static List<ItemInfo> AllItems = new List<ItemInfo>
{
        new ItemInfo{ID = 1, ItemType = ItemType.Shop, Name = "Wasserflasche", usable = true, Thirst = 50, Hunger = 0, Weight = 0.50m, SalesPrice = 2.50m, PurchasePrice = 5,  ItemUseAnimation = new Animation("Trinken", "amb@world_human_drinking@coffee@female@idle_a", "idle_a", (AnimationFlags.OnlyAnimateUpperBody | AnimationFlags.AllowPlayerControl)) },
        new ItemInfo{ID = 2, ItemType = ItemType.Sale, Name = "Sandwich", usable = true, Thirst = 0, Hunger = 50, Weight = 0.5m, PurchasePrice = 10, SalesPrice = 5, ItemUseAnimation = new Animation("Essen", "mp_player_inteat@pnq", "intro", 0) },
        new ItemInfo{ID = 3, ItemType = (ItemType.Shop|ItemType.Process), Name = "Apfel", FarmType = FarmTypes.Apfel, usable = true, Thirst = 25, Hunger = 25, Weight = 0.5m, PurchasePrice = 5, SalesPrice = 2, ItemFarmAnimation = new Animation("Apfel", "amb@prop_human_movie_bulb@base","base", AnimationFlags.Loop)},
        new ItemInfo{ID = 4, ItemType = ItemType.Process, Name = "Brötchen", usable = true, Thirst = -10, Hunger = 40, Weight = 0.5m, PurchasePrice = 7.50m, SalesPrice = 4}
}

然后我循环遍历列表并询问是否设置了标志 ItemType.Shop，如下所示：

List<ItemInfo> allShopItems = ItemInfo.AllItems.ToList();
foreach(ItemInfo i in allShopItems)
{
    if (i.ItemType.HasFlag(ItemType.Shop))
    {
        API.consoleOutput(i.Name);
    }
}

这是我的循环的输出 - 它显示了列表中的所有项目，在这种情况下 .HasFlag 方法总是 returns true。

Wasserflasche
Sandwich
Apfel
Brötchen

Answer 1

尝试为您的枚举赋值

[Flags]
public enum ItemType 
{
    Shop = 1,
    Farm = 2,
    Weapon = 4,
    Process = 8,
    Sale = 16
}

这里有一些 Guidelines for FlagsAttribute and Enum（摘自 Microsoft Docs）

仅当要对数值执行按位运算（AND、OR、EXCLUSIVE OR）时，才将 FlagsAttribute 自定义特性用于枚举。
以2的幂定义枚举常量，即1、2、4、8等。这意味着组合枚举常量中的各个标志不会重叠。

Answer 2

您应该为您的枚举赋值。 flags 属性所做的只是更改 ToString 方法的工作方式。我会使用按位运算符来减少出错的可能性：

[Flags]
public enum ItemType
{
    Shop = 1 << 0, // == 1
    Farm = 1 << 1, // == 2
    Weapon = 1 << 2, // == 4
    Process = 1 << 3, // == 8
    Sale = 1 << 4 // == 16
}

Enum.HasFlag 未按预期工作

Enum.HasFlag is not working as expected

c#

enums

flags