Author: Jonas Bilinkevicius

How to dynamically retrieve class information

Answer:

This will create an instance of the class specified in the GetClass call:

1   procedure TForm1.FormCreate(Sender: TObject);
2   begin
3     {This only works for classes registered using RegisterClass}
4     RegisterClasses([TButton, TForm]);
5   end;
6   
7   procedure TForm1.Button1Click(Sender: TObject);
8   var
9     CRef: TPersistentClass;
10    PTI: PTypeInfo;
11    AControl: TControl;
12  begin
13    CRef := GetClass('TButton');
14    if CRef <> nil then
15    begin
16      AControl := TControl(TControlClass(CRef).Create(Self));
17      with AControl do
18      begin
19        Parent := Self;
20        Width := 50;
21        Height := 30;
22      end;
23      Inc(Id);
24    end
25    else
26      MessageDlg('No such class', mtWarning, [mbOk], 0);
27  end;