WCI Data Tags (This library provides data tags that retrieve WebCenter Interation (WCI) related data for use in creating links or finding out information about the current WCI page.<p>Data tags provide content for display tags, which format and display the content. The purpose of data tags is to retrieve various WCI data and set it in tag variables where the data is accessible for display tags. Display tags, such as the value tag in logic library or any of the tags in plugnav tag library, formats the data and generate HTML or javascript from it. For example, the plugnav:ptddmenutab tag generates HTML for a DHTML dropdown menu. It needs data from a data tag to populate the menu. Data tags are defined with a tag variable id. This id is passed to the plugnav:ptddmenutab through an attribute to tell the display tag where to find the data. </p><p>Data in tag variables is accessible from tag XML in portlets and layouts. The value of this is used to pass in Tag variable references as Tag attribute values, which allow portlet and layout developers to create portlets and layouts with dynamic data with XHTML in HTML files. It is no longer necessary to use IDK to retrieve WCI data. </p><p><b>Example:</b><br/><code><pt:ptdata.mandatorylinknamedata pt:key="title" /><br/><pt:logic.value pt:value="$title"/> // Outputs name of the current Page <br/></code></p><p>The syntax for tag variable reference is the '$' character followed by the Tag variable name.</p>The mandatorylinknamedata tag sets a String value in the Tag variable. Most data tags set a data collections, bags of properties where each property is name/value pair. Properties in data collections are referenced in Tag attributes by appending '.' and the property name after the Tag variable name. The available properties on each data collection is described in the TagDocs for each data tag. The example below shows how to access the pageid property of the data collection that ptdata.currpagedata tag sets in the 'currpage' Tag variable. <p><b>Example:</b><br/><code><pt:ptdata.currpagedata pt:id="currpage" pt:noarray="true" /><br/><pt:logic.value pt:value="$currpage.pageid"/> // Outputs the value of the pageid property in data collection in 'currpage' Tag variable<br/></code></p><p>Note that referencing Tag variables with the '$' notation only works inside Adaptive Tag attributes. Using a Tag variable reference within an HTML elements willnot work. Use the core.html tag to insert values in Tag variables to HTML elements. <p><b>Example:</b><br/><code><pt:ptdata.currpagedata pt:id="currpage" pt:noarray="true" /><br/><a href="$currpage.url">$currpage.title</a> // this does not work<br/><pt:core.html pt:tag="a" url="$currpage.url" /><pt:logic.value pt:value="#currpage.title"/></pt:core.html> // correct way <br/></code></p><p>It is possible to aggregate data collections from multiple data tags into a single Tag variable. This is useful for creating a list of entries to use in for example a menu. By default, if a Tag variable contains one or more data collections (a list of collections), adding additional data collections to the Tag variable appends it to the existing collection list. The example below shows how data collections from three data tags are added to a single Tag variable. The result is one list of data collections containint data collections from all three data tags. <br/><br/><b>Example:</b><br/><code><pt:ptdata.currcommunitypagesdata pt:id="menu1" /><br/><pt:ptdata.communityactionsdata pt:id="menu1" /><br/><pt:ptdata.administrationdata pt:id="menu1" /><br/></code></p><p>Data collections in lists are accessed from Tag expression language by iterating over the list using the logic.foreach tag. Tags in the plugnav tag library also expect Tag variables with list of data collections. <br/><br/><b>Example:</b><br/><code><pt:logic.foreach pt:data="menu1" pt:var="curr" /><br/> <pt:logic.value pt:value="" /><br/></pt:logic.foreach><br/></code></p><p>Note that by default data tags will create a list in a Tag variable even if the data tag only returns a single data collection. To avoid having to use a logic.foreach tag to iterate over a single data collection, use the 'noarray' attribute. Passing 'true' as value will tell the data tag to set the data collection directly in the Tag attribute without the list. This only works for data tags that always sets a single data collection. This attribute does not do anything for data tags returning multiple data collections. See TagDocs for each tag to find out whether a tag returns a single or multiple data collections. </p>)