获得 MDI 窗体创建和释放的方法

var  wc:TWinControl;begin  // Hook 到消息，有某个MDI窗体被关闭了。  case Msg.Msg of    WM_MDICreate:begin      FDuoLog.LogIt('MDI Create : ' + IntToStr(Msg.LParam) + ',' + IntToStr(Msg.WParam));    end;    WM_MDIDestroy:begin      FDuoLog.LogIt('MDI Destroy : ' + IntToStr(Msg.LParam) + ',' + IntToStr(Msg.WParam));    end;    WM_PARENTNOTIFY:begin      case Msg.WParamLo of        WM_CREATE:begin          wc := FindControl(Msg.LParam); // LParam = Form.Handle          if (wc <> nil) and (wc is TForm) then            FDuoLog.LogItFormat('窗体 "%s" 创建。',[TForm(wc).Caption]);        end;        WM_DESTROY:begin          wc := FindControl(Msg.LParam); // LParam = Form.Handle          if (wc <> nil) and (wc is TForm) then            FDuoLog.LogItFormat('窗体 "%s" 释放。',[TForm(wc).Caption]);        end;      end;    end;  end;end;