得到一个负数(-2147483392) 我不明白为什么它(正确)转换为标志枚举. 特定 [Flags]public enum ReasonEnum{ REASON1 = 1 0, REASON2 = 1 1, REASON3 = 1 2, //etc more flags //But the ones that matter for this are REASON9 = 1 8
我不明白为什么它(正确)转换为标志枚举.
特定
[Flags] public enum ReasonEnum { REASON1 = 1 << 0, REASON2 = 1 << 1, REASON3 = 1 << 2, //etc more flags //But the ones that matter for this are REASON9 = 1 << 8, REASON17 = 1 << 31 }
为什么以下正确报告REASON9和REASON17基于负数?
var reason = -2147483392; ReasonEnum strReason = (ReasonEnum)reason; Console.WriteLine(strReason);
.NET小提琴here
我说得对,因为这是一个从COM组件触发的事件原因属性,并且当作为枚举值进行转换时,它所投射的值是正确的(根据该事件).标志枚举是根据COM对象的SDK文档. COM对象是第三方,我无法控制数字,基于接口,它将始终作为INT提供
最顶部的位集(在Int32的情况下为第31位)表示负数(有关详细信息,请参阅 two’s complement):int reason = -2147483392; string bits = Convert.ToString(reason, 2).PadLeft(32, '0'); Console.Write(bits);
结果:
10000000000000000000000100000000 ^ ^ | 8-th 31-th
所以你有
-2147483392 == (1 << 31) | (1 << 8) == REASON17 | REASON9