Question

我有两个这样的课程：

unit Unit2;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs,
  FMX.Controls.Presentation, FMX.StdCtrls, System.Generics.Collections;

type
  TForm2 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    ButtonList : TList<TButton>;
    procedure ButtonClick(Sender: TObject);
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form2: TForm2;

implementation

{$R *.fmx}

procedure TForm2.ButtonClick(Sender: TObject);
var
    pos : Integer;
begin
    pos := ButtonList.IndexOf(TButton(Sender));
    TButton(Sender).Parent := nil;
    ButtonList.Delete(pos);
end;

procedure TForm2.FormCreate(Sender: TObject);
begin
    ButtonList := TList<TButton>.Create;
end;

procedure TForm2.Button1Click(Sender: TObject);
var
    pos : Integer;
begin
    pos := ButtonList.Add(TButton.Create(nil));
    ButtonList.Items[pos].Parent := Form2;
    ButtonList.Items[pos].Position.Y := 50 * ButtonList.Count;
    ButtonList.Items[pos].OnClick := ButtonClick;
end;

end.

我现在想拥有一个包含密钥A的B类的字典。像这样：

gem install json

我不知道Swift中是否有类似的东西。有谁知道如何做到这一点？或者另一种方式来获得某种不同B的列表？

Answer 1

试试这个：

var dict: [A : B<A>.Type]

并将值保存为dict[a] = T.self，其中T: B。

包含Swift 3中通用键的特定泛型类型的字典

1 个答案: