将枚举转换为另一个枚举

Question

我有两个枚举：

public enum Fruits
{
    Apple = 1,
    Banana = 2,
    Strawberry = 3,
    Blueberry = 4
}

public enum FruitsCombined
{
    Apple = 1,
    Banana = 2,
    Berries = 0  //Strawberry and Blueberry combined
}

我有一个 Combobox，它绑定到FruitsCombined枚举，但在后台，当我 select Berries时，我想说它是Fruits枚举中的 3 和 4。

我怎样才能做到这一点？

例如，我想用两个枚举替换它以获得更好的方法：

if ((int)cboFilterFruitType.SelectedValue == 0)
{
    order = order.FindAll(o => o.FruitID == 3 || o.FruitID == 4);
}
else
{
    order = order.FindAll(o => o.FruitID == (int) cboFilterFruitType.SelectedValue);
}

Answer 1

您可以使用flags枚举：

[Flags]
public enum Fruits
{
    Apple = 1,
    Banana = 2,
    Strawberry = 4,
    Blueberry = 8
}

public enum FruitsCombined
{
    Apple = 1,
    Banana = 2,
    Berries = Fruits.Strawberry | Fruits.Blueberry //Strawberry and Blueberry combined
}

现在您可以将一个转换为另一个：

FruitsCombined fruitCombined = FruitsCombined.Berries;
Fruits fruit = (Fruits)fruitCombined; // Fruits.Strawberry | Fruits.Blueberry

如果你想检查它是否是浆果，你可以使用Enum.HasFlag ：

bool isBerry = fruit.HasFlag(Fruits.Strawberry | Fruits.Blueberry);

Answer 2

如果您可以控制这两个枚举，则可以使用评论中建议的标志将这些枚举组合在一起。

[Flags]
public enum Fruits
{
    None = 0,
    Apple = 1,
    Banana = 2,
    Strawberry = 4,
    Blueberry = 8,
    Berries = Strawberry | Blueberry
}

那么如果你有这样的代码

var fruit = Fruits.Berries;
Console.WriteLine(fruit.HasFlag(Strawberry));
Console.WriteLine(fruit.HasFlag(Blueberry));

两条写入行都将打印为真。

Answer 3

正如 stuartd 链接所说，做一些更像

变为二的幂

public enum Fruits
{
    Apple = 1,
    Banana = 2,
    Strawberry = 4,
    Blueberry = 8
}

然后你可以使用 bitwise 来表示任何组合

var appBann = Fruits.Apple | Suits.Banana;

或浆果 = Fruits.Strawberry | 西装.蓝莓

你甚至可以把它作为一个枚举

  public enum Fruits
    {
        Apple = 1,
        Banana = 2,
        Strawberry = 4,
        Blueberry = 8,
        Berries = Strawberry | Blueberry
    }

 order = order.FindAll(o => o.FruitID == (int)Fruits.Berries);