delphi - 标记/取消标记一组枚举中的另一个选项

Question

我在组件中有一组枚举，如下所示:

type
  TOption = (clVisible, clVisibleAlways, clRenderable, clEditable);
  TOptions = set of TOption;

const 
  defaultOptions = [clVisible, clRenderable];

type
  TMyComp = class(TComponent)
  private
    FOptions: TOptions;
    procedure SetOptions(const Value: TOptions);
  public
    property Options: TOptions read FOptions write SetOptions default defaultOptions;

...

procedure TMyComp.SetOptions(const Value: TOptions);
var
  ToBeSet, ToBeCleared: TOptions;
begin
  if FOptions <> Value then
    begin
      ToBeCleared:= FOptions - Value;
      ToBeSet:= Value - FOptions;

      FOptions:= Value;

      //clVisible -> clRenderable
      if (clVisible in ToBeSet) and (clRenderable in ToBeCleared)  then
        begin
          Include(FOptions, clRenderable);
          Include(ToBeSet, clRenderable);
        end;

      //not clRenderable -> not clVisible
      if (clRenderable in ToBeCleared) and (clVisible in ToBeSet)  then
        begin
          Exclude(FOptions, clVisible);
          Exclude(ToBeSet, clVisible);
        end;

      //not clVisible -> not clVisibleAlways
      if (clVisible in ToBeCleared) and (clVisibleAlways in ToBeSet) then
        begin
          Exclude(FOptions, clVisibleAlways);
          Exclude(ToBeSet, clVisibleAlways);
        end;

      //clVisibleAlways -> clVisible
      if (clVisibleAlways in ToBeSet) and (clVisible in ToBeCleared) then
        begin
          Include(FOptions, clVisible);
          Include(ToBeSet, clVisible);
        end;
  end;
end;

我想做但行不通的是:

• 如果检查了 clVisibleAlways，还检查 clVisible
• 如果检查了 clVisible，还检查 clRenderable
• 如果未选中 clRenderable，也取消选中 clVisible
• 如果未选中 clVisible，也取消选中 clVisibleAlways

请对这个主题给予一些支持。

Answer 1

我认为你的方法不必要地复杂。

更新

必须清楚地区分添加或删除选项(我之前没有这样做)。更新后的代码做到了这一点，并且在 Delphi 10.1 Berlin 中运行良好。我的测试组件名为 TNewButton，基于 TButton。

procedure TNewButton.SetOptions(const Value: TOptions);
var
  Opts: TOptions; { Because of "const"; you can also remove "const" 
                    and use Value instead of Opts. }
begin
  if FOptions <> Value then
  begin
    Opts := Value;
    { Find out if we are adding or removing an option. }
    if Opts - FOptions <> [] then
    begin
      { We are adding an option. }
      if clVisibleAlways in Opts then
        Include(Opts, clVisible);
      if clVisible in Opts then
        Include(Opts, clRenderable)
    end
    else
    begin
      { We are removing an option. }
      if not (clRenderable in Opts) then
        Exclude(Opts, clVisible);
      if not (clVisible in Opts) then
        Exclude(Opts, clVisibleAlways);
    end;
    FOptions := Opts;
  end;
end;

我对其进行了多次测试，并且至少在我的对象检查器中，它完全符合您的要求。