uses ExtCtrls;
procedure TForm1.Button1Click(Sender: TObject);
var
 myClassFinder: TClassFinder;
 mygraphclass: TGraphicClass;
begin
 { Make sure the classes are registered so that GetClass will work. }
 { Usually, this goes in the initialization section, where it is only executed once. }
 RegisterClasses([TIcon, TBitmap, TButton, TShape, TImage, TMetafile]);
 try
 myClassFinder := TClassFinder.Create(TIcon, False);
 mygraphclass := TGraphicClass(myClassFinder.GetClass(Edit2.Text));
// mygraphclass := TGraphicClass(GetClass(Edit2.Text)); // I works as well.
 Edit1.Text := GraphicExtension(mygraphclass);
 except
 on EAccessViolation do
 MessageDlg('Invalid class name.', mtError, [mbOK], 0)
 end;
end;