Delphi字典释放

type
  TUtilProcedure = procedure(var AJsonValue: TJSONObject);

  TCallback = class
  private
    FName: string;
    FProcedure: TUtilProcedure;
    FAnnotation: string;
  public
    constructor Create(AName: string; AProcedure: TUtilProcedure; AAnnotation: string); overload;
    constructor Create(ACallback: TCallback); overload;
    property Name: string read FName;
    property Proc: TUtilProcedure read FProcedure;
    property Annotation: string read FAnnotation;
 end;

然后我有一个全局变量：

procedures: TDictionary<string, TCallback>;

在OnFormActivate过程中我初始化过程变量：

procedures := TDictionary<string, TCallback>.Create();
procedures.Add('something', TCallback.Create('sth', @proc, 'annotation')); 
// ....

然后在OnFormClose中我释放它：

procedures.Clear;
procedures.Free;

我的代码是否泄漏内存？如果是这样,解释字典的正确方法是什么？
据我所知,迭代不是好主意.

如果您需要将对象存储在字典中,则采用TObjectDictionary表示更好的方法.

如果希望自动释放字典中包含的对象,请在创建集合实例时使用doOwnsValues标志.

>当变量实际上是全局变量(即在单元的接口部分中声明为var)时,应在单元本身的初始化和完成部分中创建和销毁变量.

. . .
var
  procedures: TObjectDictionary<string, TCallback>;
. . .
initialization
  procedures:= TObjectDictionary<string, TCallback>.Create([doOwnsValues]);
finalization
  procedures.Free;

>当您的变量属于表单类本身时,您应该在表单的OnCreate事件中创建字典.

. . .
public
  procedures: TObjectDictionary<string, TCallback>;
. . .
procedure TForm1.FormCreate(Sender: TObject);
begin
  procedures:= TObjectDictionary<string, TCallback>.Create([doOwnsValues]);
end;

在表单的OnDestroy事件中释放字典：

procedure TForm1.FormDestroy(Sender: TObject);
begin
  procedures.Free;
end;

>此外,如果您希望访问属于该类的变量而无需类本身的实例(这在许多编程语言中称为静态变量),您可以将字典声明为类var并可选通过类属性访问它;在这种情况下,最好在类构造函数和类析构函数中创建和销毁集合.

. . .
TMyClass = class
  private
    class constructor Create;
    class destructor Destoy;
  public
    class var procedures: TObjectDictionary<string, TCallback>;
end;
. . .
class constructor TMyClass.Create;
begin
  procedures := TObjectDictionary<string, TCallback>.Create([doOwnsValues]);
end;

class destructor TMyClass.Destoy;
begin
  procedures.Free;
end;

TCallback = class
  private
    FName: string;
    FProcedure: TUtilProcedure;
    FAnnotation: string;
  public
    constructor Create(AName: string; AProcedure: TUtilProcedure; AAnnotation: string); overload;
    constructor Create(ACallback: TCallback); overload;
    property Name: string read FName;
    property Proc: TUtilProcedure read FProcedure;
    property Annotation: string read FAnnotation;
end;

作为旁注,TCallback类不需要指定析构函数,因为它只拥有两个字符串和一个指向过程的指针.因此从TObject继承的默认析构函数就足够了.