QXmlItem Class Reference
[QtXmlPatterns module]

Detailed Description

The QXmlItem class contains either an XML node or an atomic value.

In XQuery, all expressions evaluate to a sequence of items, where each item is either an XML node or an atomic value. The query in the following snippet evaluates to sequence of five items.

 <aNode/>,
 xs:base64Binary("FFFF"),
 current-date(),
 3e3, (: A floating point value :)
 attribute {"name"} {()}

The five items are: An element, an atomic value (binary data encoded in base64), a date, a float, and an attribute.

QXmlItem is the class that represents these XQuery items in the QtXmlPatterns API. A non-null instance of QXmlItem is either a node or an atomic value. Calling isNode() or isAtomicValue() tells you which it is. Atomic values are represented elsewhere in the Qt API as instances of QVariant, and an instance of QXmlItem that represents an atomic value can be converted to a QVariant by calling toAtomicValue(). A QXmlItem that wraps a node is represented elsewhere as an instance of QXmlNodeModelIndex. A node QXmlItem can be converted to a QXmlNodeModelIndex by calling toNodeModelIndex().

A default constructed QXmlItem instance is neither a node nor an atomic value. It is considered null, in which case isNull() returns true.

An instance of QXmlItem will be left dangling if the XML node model it refers to is deleted, if it is a QXmlNodeModelIndex.

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