c# - 获取所有包含标志

Question

我有一个包含一些标志的变量，以及我如何能够检查设置了哪些标志的变量。

我的旗帜。

[Flags]
    public enum Button{ 
        //Can't have more than 30 flags
        //If an enum is added or deleted need to change for loop in method AddButton

        // Exit flags
        Exit = 1 << 0, 
        Cancel = 1 << 1, 
        Abort = 1 << 2,
        Close = 1 << 3,

        //Proced flags
        Accept = 1 << 4, 
        Ok = 1 << 5,
        Submit = 1 << 6,

        //Question flags
        No = 1 << 7,
        Yes = 1 << 8,

        //Save and load
        Save = 1 << 9,
        SaveAll = 1 << 10,
        SaveNew = 1 << 11,
        Open = 1 << 12,
        Load = 1 << 12
    }

这是我检查我的标志的地方

    for (int i = 1; i <= 12; ++i) {
        if((buttons & 1 << i) == 1 << i){

        }
    }

显然我不能用这种方式来检查标志。

为了清楚起见，我想知道按钮中设置了哪些标志。

更新：我不能使用 Enum.hasFlag() 因为我在 Unity 中制作游戏并且它使用 Mono。显然 Mono 还不支持 hasFlag。

Answer 1

我从这篇文章中提取了这个，这很有帮助。它展示了如何使用具有位移和按位信息的枚举。

http://www.codeducky.org/ins-outs-c-enums/

// this attribute isn't strictly necessary, but it provides
// useful metadata and greatly improves the ToString() representation
[Flags]
enum BookFlags
{
    // most flags enums provide a named None or Default
    // zero value to represent the empty set
    Default = 0,
    HardCover = 1,
    InStock = HardCover << 1, // 2
    HasEBook = InStock << 1, // 4
    OnSale = HasEBook << 1, // 8
}

// we can create and test flag sets with bitwise operations
BookFlags flags = BookFlags.HardCover | BookFlags.InStock;
var text = flags.ToString(); // HardCover, InStock
var isInStock = (flags & BookFlags.InStock) == BookFlags.InStock; // true
// testing for a particular flag is also simplified by the HasFlag extension
var isInStock2 = flags.HasFlag(BookFlags.InStock); // true

编辑：如果你不能使用 HasFlag，你可能想要这样的东西。

// i redefined your enum a bit
public enum Buttons
{
    // Default
    Default = 0,

    // Exit flags
    Exit = 1,
    Cancel = Exit << 1,
    Abort = Cancel << 1,
    Close = Abort << 1,

    //Proced flags
    Accept = Close << 1,
    Ok = Accept << 1,
    Submit = Ok << 1,

    //Question flags
    No = Submit << 1,
    Yes = No << 1,

    //Save and load
    Save = Yes << 1,
    SaveAll = Save << 1,
    SaveNew = SaveAll << 1,
    Open = SaveNew << 1,
    Load = Open << 1
}

然后你可以...

        // here's checking a selection of buttons against the complete enum universe of values
        var lastButton = Convert.ToInt32(Enum.GetValues(typeof(Buttons)).Cast<Buttons>().Max());
        int enumCheck;

        Buttons flags = Buttons.Ok | Buttons.SaveNew | Buttons.Load | Buttons.No | Buttons.Submit | Buttons.Exit;

        for (int i = 0; Math.Pow(2, i) <= lastButton; i++)
        {
            enumCheck = (int)Math.Pow(2, i);

            if ((flags & (Buttons)enumCheck) == (Buttons)enumCheck)
            {
                Debug.WriteLine(Enum.GetName(typeof(Buttons), enumCheck));
            }
        }

产生输出（注意顺序）：

Exit
Ok
Submit
No
SaveNew
Load

Answer 2

只需投射buttons到int. 你可能想确保你的循环以 开头0，否则你会错过一次检查。

for (int i = 0; i <= 12; ++i)
{
    if (((int)buttons & 1 << i) == 1 << i)
    {

    }
}