I separately downloaded qt creator from qt digia site but it was disappointing that it does not include qt designer, so i had to research a bit and download the qt designer separately today.
Qt is a cross-platform application development framework. Some of the well known applications developed with Qt are KDE, Opera, Google Earth and Skype. Qt was first publicly released on May 1995. It is dual licensed. That means, it can be used for creating open source applications as well as commercial ones. Qt toolkit is a very powerful toolkit. It is well established in the open source community.
use +command as name of propery (command can be replaced with any command name)
and string value: "import maya.cmds;maya.cmds.ToggleGrid()"