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Breadcrumbs go here --> <li><a href="modules.html">Modules</a></li> <li><a href="qtdeclarative.html">QtDeclarative</a></li> <li>QDeclarativeListReference</li> </ul> </div> <div class="toolbuttons toolblock"> <ul> <li id="smallA" class="t_button">A</li> <li id="medA" class="t_button active">A</li> <li id="bigA" class="t_button">A</li> <li id="print" class="t_button"><a href="javascript:this.print();"> <span>Print</span></a></li> </ul> </div> </div> <div class="content mainContent"> <div class="toc"> <h3><a name="toc">Contents</a></h3> <ul> <li class="level1"><a href="#public-functions">Public Functions</a></li> <li class="level1"><a href="#details">Detailed Description</a></li> </ul> </div> <h1 class="title">QDeclarativeListReference Class Reference</h1> <!-- $$$QDeclarativeListReference-brief --> <p>The QDeclarativeListReference class allows the manipulation of <a href="qdeclarativelistproperty.html">QDeclarativeListProperty</a> properties. <a href="#details">More...</a></p> <!-- @@@QDeclarativeListReference --> <pre class="cpp"> <span class="preprocessor">#include <QDeclarativeListReference></span></pre><p>This class was introduced in Qt 4.7.</p> <ul> <li><a href="qdeclarativelistreference-members.html">List of all members, including inherited members</a></li> </ul> <a name="public-functions"></a> <h2>Public Functions</h2> <table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#QDeclarativeListReference">QDeclarativeListReference</a></b> ()</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#QDeclarativeListReference-2">QDeclarativeListReference</a></b> ( QObject * <i>object</i>, const char * <i>property</i>, QDeclarativeEngine * <i>engine</i> = 0 )</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#append">append</a></b> ( QObject * <i>object</i> ) const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> QObject * </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#at">at</a></b> ( int <i>index</i> ) const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#canAppend">canAppend</a></b> () const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#canAt">canAt</a></b> () const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#canClear">canClear</a></b> () const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#canCount">canCount</a></b> () const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#clear">clear</a></b> () const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#count">count</a></b> () const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#isValid">isValid</a></b> () const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> const QMetaObject * </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#listElementType">listElementType</a></b> () const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> QObject * </td><td class="memItemRight bottomAlign"><b><a href="qdeclarativelistreference.html#object">object</a></b> () const</td></tr> </table> <a name="details"></a> <!-- $$$QDeclarativeListReference-description --> <div class="descr"> <h2>Detailed Description</h2> <p>The QDeclarativeListReference class allows the manipulation of <a href="qdeclarativelistproperty.html">QDeclarativeListProperty</a> properties.</p> <p>QDeclarativeListReference allows C++ programs to read from, and assign values to a QML list property in a simple and type safe way. A QDeclarativeListReference can be created by passing an object and property name or through a <a href="qdeclarativeproperty.html">QDeclarativeProperty</a> instance. These two are equivalant:</p> <pre class="cpp"> <span class="type">QDeclarativeListReference</span> ref1(object<span class="operator">,</span> <span class="string">"children"</span>); <span class="type"><a href="qdeclarativeproperty.html">QDeclarativeProperty</a></span> ref2(object<span class="operator">,</span> <span class="string">"children"</span>); <span class="type">QDeclarativeListReference</span> ref2 <span class="operator">=</span> qvariant_cast<span class="operator"><</span><span class="type">QDeclarativeListReference</span><span class="operator">></span>(ref2<span class="operator">.</span>read());</pre> <p>Not all QML list properties support all operations. A set of methods, <a href="qdeclarativelistreference.html#canAppend">canAppend</a>(), <a href="qdeclarativelistreference.html#canAt">canAt</a>(), <a href="qdeclarativelistreference.html#canClear">canClear</a>() and <a href="qdeclarativelistreference.html#canCount">canCount</a>() allow programs to query whether an operation is supported on a given property.</p> <p>QML list properties are typesafe. Only <a href="qobject.html">QObject</a>'s that derive from the correct base class can be assigned to the list. The <a href="qdeclarativelistreference.html#listElementType">listElementType</a>() method can be used to query the <a href="qmetaobject.html">QMetaObject</a> of the <a href="qobject.html">QObject</a> type supported. Attempting to add objects of the incorrect type to a list property will fail.</p> <p>Like with normal lists, when accessing a list element by index, it is the callers responsibility to ensure that it does not request an out of range element using the <a href="qdeclarativelistreference.html#count">count</a>() method before calling <a href="qdeclarativelistreference.html#at">at</a>().</p> </div> <!-- @@@QDeclarativeListReference --> <div class="func"> <h2>Member Function Documentation</h2> <!-- $$$QDeclarativeListReference[overload1]$$$QDeclarativeListReference --> <h3 class="fn"><a name="QDeclarativeListReference"></a>QDeclarativeListReference::<span class="name">QDeclarativeListReference</span> ()</h3> <p>Constructs an invalid instance.</p> <!-- @@@QDeclarativeListReference --> <!-- $$$QDeclarativeListReference$$$QDeclarativeListReferenceQObject*constchar*QDeclarativeEngine* --> <h3 class="fn"><a name="QDeclarativeListReference-2"></a>QDeclarativeListReference::<span class="name">QDeclarativeListReference</span> ( <span class="type"><a href="qobject.html">QObject</a></span> * <i>object</i>, const <span class="type">char</span> * <i>property</i>, <span class="type"><a href="qdeclarativeengine.html">QDeclarativeEngine</a></span> * <i>engine</i> = 0 )</h3> <p>Constructs a <a href="qdeclarativelistreference.html">QDeclarativeListReference</a> for <i>object</i>'s <i>property</i>. If <i>property</i> is not a list property, an invalid <a href="qdeclarativelistreference.html">QDeclarativeListReference</a> is created. If <i>object</i> is destroyed after the reference is constructed, it will automatically become invalid. That is, it is safe to hold <a href="qdeclarativelistreference.html">QDeclarativeListReference</a> instances even after <i>object</i> is deleted.</p> <p>Passing <i>engine</i> is required to access some QML created list properties. If in doubt, and an engine is available, pass it.</p> <!-- @@@QDeclarativeListReference --> <!-- $$$append[overload1]$$$appendQObject* --> <h3 class="fn"><a name="append"></a><span class="type">bool</span> QDeclarativeListReference::<span class="name">append</span> ( <span class="type"><a href="qobject.html">QObject</a></span> * <i>object</i> ) const</h3> <p>Appends <i>object</i> to the list. Returns true if the operation succeeded, otherwise false.</p> <p><b>See also </b><a href="qdeclarativelistreference.html#canAppend">canAppend</a>().</p> <!-- @@@append --> <!-- $$$at[overload1]$$$atint --> <h3 class="fn"><a name="at"></a><span class="type"><a href="qobject.html">QObject</a></span> * QDeclarativeListReference::<span class="name">at</span> ( <span class="type">int</span> <i>index</i> ) const</h3> <p>Returns the list element at <i>index</i>, or 0 if the operation failed.</p> <p><b>See also </b><a href="qdeclarativelistreference.html#canAt">canAt</a>().</p> <!-- @@@at --> <!-- $$$canAppend[overload1]$$$canAppend --> <h3 class="fn"><a name="canAppend"></a><span class="type">bool</span> QDeclarativeListReference::<span class="name">canAppend</span> () const</h3> <p>Returns true if the list property can be appended to, otherwise false. Returns false if the reference is invalid.</p> <p><b>See also </b><a href="qdeclarativelistreference.html#append">append</a>().</p> <!-- @@@canAppend --> <!-- $$$canAt[overload1]$$$canAt --> <h3 class="fn"><a name="canAt"></a><span class="type">bool</span> QDeclarativeListReference::<span class="name">canAt</span> () const</h3> <p>Returns true if the list property can queried by index, otherwise false. Returns false if the reference is invalid.</p> <p><b>See also </b><a href="qdeclarativelistreference.html#at">at</a>().</p> <!-- @@@canAt --> <!-- $$$canClear[overload1]$$$canClear --> <h3 class="fn"><a name="canClear"></a><span class="type">bool</span> QDeclarativeListReference::<span class="name">canClear</span> () const</h3> <p>Returns true if the list property can be cleared, otherwise false. Returns false if the reference is invalid.</p> <p><b>See also </b><a href="qdeclarativelistreference.html#clear">clear</a>().</p> <!-- @@@canClear --> <!-- $$$canCount[overload1]$$$canCount --> <h3 class="fn"><a name="canCount"></a><span class="type">bool</span> QDeclarativeListReference::<span class="name">canCount</span> () const</h3> <p>Returns true if the list property can be queried for its element count, otherwise false. Returns false if the reference is invalid.</p> <p><b>See also </b><a href="qdeclarativelistreference.html#count">count</a>().</p> <!-- @@@canCount --> <!-- $$$clear[overload1]$$$clear --> <h3 class="fn"><a name="clear"></a><span class="type">bool</span> QDeclarativeListReference::<span class="name">clear</span> () const</h3> <p>Clears the list. Returns true if the operation succeeded, otherwise false.</p> <p><b>See also </b><a href="qdeclarativelistreference.html#canClear">canClear</a>().</p> <!-- @@@clear --> <!-- $$$count[overload1]$$$count --> <h3 class="fn"><a name="count"></a><span class="type">int</span> QDeclarativeListReference::<span class="name">count</span> () const</h3> <p>Returns the number of objects in the list, or 0 if the operation failed.</p> <!-- @@@count --> <!-- $$$isValid[overload1]$$$isValid --> <h3 class="fn"><a name="isValid"></a><span class="type">bool</span> QDeclarativeListReference::<span class="name">isValid</span> () const</h3> <p>Returns true if the instance refers to a valid list property, otherwise false.</p> <!-- @@@isValid --> <!-- $$$listElementType[overload1]$$$listElementType --> <h3 class="fn"><a name="listElementType"></a>const <span class="type"><a href="qmetaobject.html">QMetaObject</a></span> * QDeclarativeListReference::<span class="name">listElementType</span> () const</h3> <p>Returns the <a href="qmetaobject.html">QMetaObject</a> for the elements stored in the list property. Returns 0 if the reference is invalid.</p> <p>The <a href="qmetaobject.html">QMetaObject</a> can be used ahead of time to determine whether a given instance can be added to a list.</p> <!-- @@@listElementType --> <!-- $$$object[overload1]$$$object --> <h3 class="fn"><a name="object"></a><span class="type"><a href="qobject.html">QObject</a></span> * QDeclarativeListReference::<span class="name">object</span> () const</h3> <p>Returns the list property's object. Returns 0 if the reference is invalid.</p> <!-- @@@object --> </div> </div> </div> </div> <div class="ft"> <span></span> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2013 Digia Plc and/or its subsidiaries. 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