public function __construct(QForm $objForm, $strGroupingId) {
			if (strlen($strGroupingId) == 0)
				$this->strGroupingId = $objForm->GenerateControlId();
			else {
				// Verify ControlId is only AlphaNumeric Characters
				$strMatches = array();
				$strPattern = '/[A-Za-z0-9]*/';
				preg_match($strPattern, $strGroupingId, $strMatches);
				if (count($strMatches) && ($strMatches[0] == $strGroupingId))
					$this->strGroupingId = $strGroupingId;
				else
					throw new QCallerException('GroupingIDs must be only alphanumeric chacters: ' . $strGroupingId);
			}
			try {
				$objForm->AddGrouping($this);
			} catch (QCallerException $objExc) {
				$objExc->IncrementOffset();
				throw $objExc;
			}
		}