my way if doing that for whole columns
$("#grid").pqGrid( 'getColumn', { dataIndx: xy}).editable = false;
for (i = 0; i < contentarray.length; i++){
$("#grid").pqGrid( "addClass", {dataIndx: xy, rowIndx: i, cls: 'yourclass'} );
}
$("#grid").pqGrid( "option" , "dataModel.data",contentarray );
$("#grid").pqGrid( "refreshDataAndView" );