怎么动态使用类?

Question

比如我声明了:
type
  xmltree = class
    public
      str:string;
  end;
  po=^xmltree;我想动态使用这个类比如xmlpoint:po;
new(xmlpoint);
xmlpoint^.str:='sjsjs';可是好象会出错这是为什么该怎么样实现他呢?请各位帮忙!

Answer 1

这不叫动态使用类,这叫动态创建对象,使用类应该用TClass,也就是类的类~~~Object Pascal中创建对象需要显式调用构造函数xmlpoint := xmltree.Create;

Answer 2

procedure TForm1.Button4Click(Sender: TObject);
var
  Myxmltree: xmltree;
begin
  Myxmltree := xmltree.Create;
  Myxmltree.str := '1234';
  ShowMessage(Myxmltree.str);
  Myxmltree.Free;
end;

Answer 3

xmlpoint:po;
new(xmlpoint);
xmlpoint^:=xmltree.Create;//创建事例
xmlpoint^.str:='sjsjs';

Answer 4

rockswj(石头) (你说的我试了好象不行哦!
ehom(？！) 你能说的更详细一点吗?谢谢了哦 !

Answer 5

我试了怎么可以：
type
  xmltree = class
    public
      str:string;
  end;
  po=^xmltree;
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
var
  Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.Button1Click(Sender: TObject);
var  xmlpoint:po;
begin
  new(xmlpoint);
  xmlpoint^:=xmltree.Create;
  xmlpoint^.str:='sjsjs';
  ShowMessage(xmlpoint^.str);
  xmlpoint^.Free;
  dispose(xmlpoint);
end;

Answer 6

xmlpoint^?????这是指针的指针??????????????