Delphi使用TStringHash实现建立类（有点像反射）

 unit Unit1;

 interface

 uses
   Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
   Dialogs, StdCtrls, jpeg, ExtCtrls,
   IniFiles;//TStringHash使用

 type
   TForm1 = class(TForm)
     Button1: TButton;
     Edit1: TEdit;
     Image1: TImage;
     procedure Button1Click(Sender: TObject);
   private
     { Private declarations }
   public
     { Public declarations }
   end;

 type
   // 边信息基类接口
   IClassInfo = interface
   ['{219E2CE1-78AE-4479-A4D8-A23DB421621C}']
     function GetName: string;
   end;
   //
   TInfoClass = class of TMyClass;
   //自定义的类
   TMyClass = class(TObject, IInterface)
   protected
     FRefCount: Integer;
   private
     FMyName: string;
   public
     function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
     function _AddRef: Integer; stdcall;
     function _Release: Integer; stdcall;
     constructor Create; virtual;
     function GetName: string; virtual;
     property  RefCount: Integer read FRefCount;
   end;
   //展示类
   TMyClass1 = class(TMyClass, IClassInfo)
   private
     FMyName: string;
   public
     constructor Create; override;
     function GetName: string; override;
   end;
   //工厂类
   TClassInfoFactroy = class
     class function CreateClass(const ATypeID: Integer): TMyClass;
   end;

 var
   Form1: TForm1;

 implementation

 {$R *.dfm}

 var
   MyClassList: TStringHash;

 { TMyClass }
 //注册类方法
 procedure RegisterMyClass(const ATypeID: Integer; AClass: TInfoClass);
 var
   num: Integer;
 begin
    num := MyClassList.ValueOf(IntToStr(ATypeID));
    if num = -  then
      MyClassList.Add(IntToStr(ATypeID), Integer(AClass))
    else
     Assert(False, Format('ElementTypeID %d ''s EdgeInfo already registered', [ATypeID]));
 end;

 constructor TMyClass.Create;
 begin
 // 子类实现
 end;

 function TMyClass.GetName: string;
 begin
 // 子类实现
 end;

 function TMyClass.QueryInterface(const IID: TGUID; out Obj): HResult;
 begin
   if GetInterface(IID, Obj) then
     Result :=
   else Result := E_NOINTERFACE;
 end;

 function TMyClass._AddRef: Integer;
 begin
   Result := InterlockedIncrement(FRefCount);
 end;

 function TMyClass._Release: Integer;
 begin
   Result := InterlockedDecrement(FRefCount);
   if Result =  then Destroy;
 end;

 { TMyClass1 }

 constructor TMyClass1.Create;
 begin
   FMyName := '类1';
 end;

 function TMyClass1.GetName: string;
 begin
   Result := FMyName;
 end;

 { TClassInfoFactroy }
 //建立类方法
 class function TClassInfoFactroy.CreateClass(const ATypeID: Integer): TMyClass;
 var
   nClass: Integer;
 begin
   nClass := MyClassList.ValueOf(IntToStr(ATypeID));
   if nClass <> - then
     Result := TInfoClass(nClass).Create
   else begin
     Result := nil;
   end;
 end;
 //调用类方法
 procedure TForm1.Button1Click(Sender: TObject);
 begin
   Edit1.Text := (TClassInfoFactroy.CreateClass() as IClassInfo).GetName;
 end;
 //初始化
 initialization
   if MyClassList = nil then
     MyClassList:= TStringHash.Create();
   // 注册类
   RegisterMyClass(, TMyClass1);

 end.