Delphi检查类型声明中的变量值

Question

如何确定变量的值是否在"类型声明"的范围内.防爆.

Type
  TManagerType = (mtBMGR, mtAMGR, mtHOOT);

...

var
  ManagerType: TManagerType;

....


procedure DoSomething;
begin
  if (ManagerType in TManagerType) then
    DoSomething
  else
    DisplayErrorMessage;
end;

谢谢,彼得.

Answer 1

InRange: Boolean;
ManagerType: TManagerType;
...
InRange := ManagerType in [Low(TManagerType)..High(TManagerType)];

正如Nickolay O.所说 - 虽然上面的布尔表达式直接对应于:

(Low(TManagerType) <= ManagerType) and (ManagerType <= High(TManagerType))

编译器不会根据单个子范围执行针对立即设置检查成员资格的优化.因此,[成熟]优化的代码将不那么优雅.