public function setPrompt($prompt)
	{
		if (empty($prompt)) {
			return $this;
		}

		if (isset($this->items)) {
			if (in_array(NULL, array_keys($this->items))) {
				throw new InvalidArgumentException(
					"There is an item whose value == null (non-strict comparison)." .
					"Setting prompt would interfere with this value.");
			}
		}
		else {
			throw new NotSupportedException('This must be a ChoiceControl');
		}

		$this->prompt = $prompt;

		return $this;
	}
public function setPrompt($prompt)
	{
		if (empty($prompt)) {
			return $this;
		}

		if (isset($this->items)) {
			if (in_array(NULL, array_keys($this->items))) {
				throw new InvalidArgumentException(
					"There is an item whose value == null (non-strict comparison)." .
					"Setting prompt would interfere with this value.");
			}
		}
		else {
			throw new NotSupportedException('This must be a ChoiceControl');
		}

		$this->prompt = $prompt;

		return $this;
	}
public function setPrompt ( $ prompt ) { if ( empty ( $ prompt ) ) { return $ this ; } if ( isset ( $ this -> items ) ) { if ( in_array ( NULL , array_keys ( $ this -> items ) ) ) { throw new InvalidArgumentException ( "There is an item whose value == null (non-strict comparison)." . "Setting prompt would interfere with this value." ) ; } } else { throw new NotSupportedException ( 'This must be a ChoiceControl' ) ; } $ this -> prompt = $ prompt ; return $ this ; }
Sets the first unselectable item on list. Its value is null.
@param null|string $prompt
@return static
Sets the first unselectable item on list . Its value is null .