Adobe 38043740 Developing Applications - Page 867

DEVELOPING COLDFUSION 9 APPLICATIONS 862 Requesting and Presenting Information {[formName:]controlName[.attributeName][@event]} {SpryDataSetName.fieldName} The brackets ([]) indicate optional contents and are not part of the parameter. Note: To include a literal brace character in a bind expression, escape the character with a backslash, as \{, \}. The formname value The formname entry identifies the form that contains the control you are binding to. Specify a form name if multiple forms contain bind targets with the same names. To specify the form name, start the bind expression with the form's id attribute the name attribute if you did not specify an id attribute, and follow it with a colon (:). To specify the book control that is in a form named inputForm, for example, use the following format: bind="cfc:myapp.bookorder.getChoices({inputForm:book})" The controlName value To bind to a form field, the controlName value must be the value of the id or name attribute of the form control to which you are binding. If a control has both an id and a name attribute, use either value. You can bind to any ColdFusion form control, including cfgrid and cftree. You cannot bind to values in other ColdFusion tags, such as cftable. To bind to a Spry data set, specify the data set name in this part of the bind parameter. You can bind to multiple radio buttons or check boxes by giving them the same name value. If all the radio buttons in a radio button group have the same name value, the bind parameter represents the selected button. If multiple check boxes have the same name value, the bind parameter represents the values of the selected controls in a commadelimited list. If you also specify a unique id attribute for each check box or radio button, specify an HTML label tag for each button or check box and use the id value in the for attribute; in this case, users select items by clicking the label, not just the button or box. If a cfselect control supports multiple selections, the bind expression returns the information about the selected items in a comma-delimited list. You can bind only to controls that are available in the DOM tree when the bind is registered. Binds are registered when the page with the bind expression loads, either in the browser window or in a container tag. As a result, if you have two cfdiv, cflayoutarea, cfpod, or cfwindow containers that you load by using a source (or for cfdiv tag, bind) attribute, you cannot bind controls in one container to controls in the other, because one container cannot be assured that the other is loaded when it loads. Similarly, elements on the main page cannot bind to elements on a dynamically loaded container. To prevent this problem, define the bind target in line on the main page, instead of using a source or bind attribute to retrieve the markup that contains the bind target. In other words, the "master" form with fields that serve as sources of bind expressions is loaded statically (on the main page), and the "child" controls that depend on the data are loaded dynamically, on a page that is specified in a source or bind attribute. The attributeName value When you bind to a form control, by default, the bind expression represents the value attribute of the specified control. If the bind target is a cfselect tag, the bind expression represents a comma delimited list of the values of the selected items. To bind to a different attribute, follow the control name or id with a period (.) and the attribute name. To pass the checked attribute of a checkbox cfinput tag as a CFC parameter, for example, use an expression such as the following: bind="cfc:myapp.bookorder.useStatus({myForm:approved.checked@click}) Last updated 1/20/2012