Gridlayout menue (3 columns) center on the screen

Hi all here,

ist there any way to bring a gridlayout (menue) with 3 columns center to screen? I want fixed width for a menue-gridlayout and allways center

APPLICATION.alert(gridlayout.getWidth()+"");

Error and Value -1 becouse it's on "auto"

APPLICATION.alert(gridlayout.getLeftMargin()+"");

gridlayout.setLeftMargin((maximized-object.getWidth()-gridlayout.getWidth())/2);

APPLICATION.alert(gridlayout.getLeftMargin()+"");

any idea?

br Harry