C#中 判断 (A == B || A == C || A == D) 只有这种写法吗？
有没有其他更简便的写法，因为 A 实在太长了
AA = A
(AA == B || AA == C || AA == D)
还有
switch(A)
case B:
case C:
case D:
doing;
或者
(A == B
|| A == C
|| A == D)