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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"><title>TinyXml: TiXmlHandle Class Reference</title><link href="doxygen.css" rel="stylesheet" type="text/css"><link href="tabs.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.4.7 --><div class="tabs"> <ul> <li><a href="index.html"><span>Main Page</span></a></li> <li id="current"><a href="annotated.html"><span>Classes</span></a></li> <li><a href="files.html"><span>Files</span></a></li> <li><a href="pages.html"><span>Related Pages</span></a></li> </ul></div><div class="tabs"> <ul> <li><a href="annotated.html"><span>Class List</span></a></li> <li><a href="hierarchy.html"><span>Class Hierarchy</span></a></li> <li><a href="functions.html"><span>Class Members</span></a></li> </ul></div><h1>TiXmlHandle Class Reference</h1><!-- doxytag: class="TiXmlHandle" -->A <a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> is a class that wraps a node pointer with null checks; this is an incredibly useful thing. <a href="#_details">More...</a><p><code>#include <<a class="el" href="tinyxml_8h-source.html">tinyxml.h</a>></code><p><a href="classTiXmlHandle-members.html">List of all members.</a><table border="0" cellpadding="0" cellspacing="0"><tr><td></td></tr><tr><td colspan="2"><br><h2>Public Member Functions</h2></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="ba18fd7bdefb942ecdea4bf4b8e29ec8"></a><!-- doxytag: member="TiXmlHandle::TiXmlHandle" ref="ba18fd7bdefb942ecdea4bf4b8e29ec8" args="(TiXmlNode *_node)" --> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#ba18fd7bdefb942ecdea4bf4b8e29ec8">TiXmlHandle</a> (<a class="el" href="classTiXmlNode.html">TiXmlNode</a> *_node)</td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Create a handle from any node (at any depth of the tree.) This can be a null pointer. <br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="236d7855e1e56ccc7b980630c48c7fd7"></a><!-- doxytag: member="TiXmlHandle::TiXmlHandle" ref="236d7855e1e56ccc7b980630c48c7fd7" args="(const TiXmlHandle &ref)" --> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#236d7855e1e56ccc7b980630c48c7fd7">TiXmlHandle</a> (const <a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> &ref)</td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Copy constructor. <br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="cdb1faaf88a700b40ca2c8d9aee21139"></a><!-- doxytag: member="TiXmlHandle::FirstChild" ref="cdb1faaf88a700b40ca2c8d9aee21139" args="() const " --><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#cdb1faaf88a700b40ca2c8d9aee21139">FirstChild</a> () const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the first child node. <br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="8c61f64ae9365d89c264f289085541f8"></a><!-- doxytag: member="TiXmlHandle::FirstChild" ref="8c61f64ae9365d89c264f289085541f8" args="(const char *value) const " --><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#8c61f64ae9365d89c264f289085541f8">FirstChild</a> (const char *value) const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the first child node with the given name. <br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="24d1112e995e937e4dddb202d4113d4a"></a><!-- doxytag: member="TiXmlHandle::FirstChildElement" ref="24d1112e995e937e4dddb202d4113d4a" args="() const " --><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#24d1112e995e937e4dddb202d4113d4a">FirstChildElement</a> () const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the first child element. <br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="f0aea751320f5e430fac6f8fff3b8dd4"></a><!-- doxytag: member="TiXmlHandle::FirstChildElement" ref="f0aea751320f5e430fac6f8fff3b8dd4" args="(const char *value) const " --><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#f0aea751320f5e430fac6f8fff3b8dd4">FirstChildElement</a> (const char *value) const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the first child element with the given name. <br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#072492b4be1acdb0db2d03cd8f71ccc4">Child</a> (const char *value, int index) const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the "index" child with the given name. <a href="#072492b4be1acdb0db2d03cd8f71ccc4"></a><br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#f9cf6a7d08a5da94a8924425ad0cd5ac">Child</a> (int index) const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the "index" child. <a href="#f9cf6a7d08a5da94a8924425ad0cd5ac"></a><br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#979a3f850984a176ee884e394c7eed2d">ChildElement</a> (const char *value, int index) const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the "index" child element with the given name. <a href="#979a3f850984a176ee884e394c7eed2d"></a><br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#8786475b9d1f1518492e3a46704c7ef0">ChildElement</a> (int index) const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return a handle to the "index" child element. <a href="#8786475b9d1f1518492e3a46704c7ef0"></a><br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlNode.html">TiXmlNode</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#f678e5088e83be67baf76f699756f2c3">ToNode</a> () const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return the handle as a <a class="el" href="classTiXmlNode.html">TiXmlNode</a>. <a href="#f678e5088e83be67baf76f699756f2c3"></a><br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlElement.html">TiXmlElement</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#bc6e7ed383a5fe1e52b0c0004b457b9e">ToElement</a> () const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return the handle as a <a class="el" href="classTiXmlElement.html">TiXmlElement</a>. <a href="#bc6e7ed383a5fe1e52b0c0004b457b9e"></a><br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlText.html">TiXmlText</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#4ac53a652296203a5b5e13854d923586">ToText</a> () const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return the handle as a <a class="el" href="classTiXmlText.html">TiXmlText</a>. <a href="#4ac53a652296203a5b5e13854d923586"></a><br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlUnknown.html">TiXmlUnknown</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#1381c17507a130767b1e23afc93b3674">ToUnknown</a> () const </td></tr><tr><td class="mdescLeft"> </td><td class="mdescRight">Return the handle as a <a class="el" href="classTiXmlUnknown.html">TiXmlUnknown</a>. <a href="#1381c17507a130767b1e23afc93b3674"></a><br></td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlNode.html">TiXmlNode</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#b44b723a8dc9af72838a303c079d0376">Node</a> () const </td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlElement.html">TiXmlElement</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#cb5fe8388a526289ea65e817a51e05e7">Element</a> () const </td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlText.html">TiXmlText</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#9fc739c8a18d160006f82572fc143d13">Text</a> () const </td></tr><tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="classTiXmlUnknown.html">TiXmlUnknown</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="classTiXmlHandle.html#49675b74357ba2aae124657a9a1ef465">Unknown</a> () const </td></tr></table><hr><a name="_details"></a><h2>Detailed Description</h2>A <a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> is a class that wraps a node pointer with null checks; this is an incredibly useful thing. <p>Note that <a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> is not part of the TinyXml DOM structure. It is a separate utility class.<p>Take an example: <div class="fragment"><pre class="fragment"> <Document> <Element attributeA = "valueA"> <Child attributeB = "value1" /> <Child attributeB = "value2" /> </Element> <Document> </pre></div><p>Assuming you want the value of "attributeB" in the 2nd "Child" element, it's very easy to write a *lot* of code that looks like:<p><div class="fragment"><pre class="fragment"> TiXmlElement* root = document.FirstChildElement( "Document" ); if ( root ) { TiXmlElement* element = root->FirstChildElement( "Element" ); if ( element ) { TiXmlElement* child = element->FirstChildElement( "Child" ); if ( child ) { TiXmlElement* child2 = child->NextSiblingElement( "Child" ); if ( child2 ) { // Finally do something useful. </pre></div><p>And that doesn't even cover "else" cases. <a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> addresses the verbosity of such code. A <a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> checks for null pointers so it is perfectly safe and correct to use:<p><div class="fragment"><pre class="fragment"> TiXmlHandle docHandle( &document ); TiXmlElement* child2 = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", 1 ).ToElement(); if ( child2 ) { // do something useful </pre></div><p>Which is MUCH more concise and useful.<p>It is also safe to copy handles - internally they are nothing more than node pointers. <div class="fragment"><pre class="fragment"> TiXmlHandle handleCopy = handle; </pre></div><p>What they should not be used for is iteration:<p><div class="fragment"><pre class="fragment"> int i=0; while ( true ) { TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", i ).ToElement(); if ( !child ) break; // do something ++i; } </pre></div><p>It seems reasonable, but it is in fact two embedded while loops. The Child method is a linear walk to find the element, so this code would iterate much more than it needs to. Instead, prefer:<p><div class="fragment"><pre class="fragment"> TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).FirstChild( "Child" ).ToElement(); for( child; child; child=child->NextSiblingElement() ) { // do something } </pre></div> <p><hr><h2>Member Function Documentation</h2><a class="anchor" name="f9cf6a7d08a5da94a8924425ad0cd5ac"></a><!-- doxytag: member="TiXmlHandle::Child" ref="f9cf6a7d08a5da94a8924425ad0cd5ac" args="(int index) const " --><div class="memitem"><div class="memproto"> <table class="memname"> <tr> <td class="memname"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> TiXmlHandle::Child </td> <td>(</td> <td class="paramtype">int </td> <td class="paramname"> <em>index</em> </td> <td> ) </td> <td width="100%"> const</td> </tr> </table></div><div class="memdoc"><p>Return a handle to the "index" child. <p>The first child is 0, the second 1, etc. </div></div><p><a class="anchor" name="072492b4be1acdb0db2d03cd8f71ccc4"></a><!-- doxytag: member="TiXmlHandle::Child" ref="072492b4be1acdb0db2d03cd8f71ccc4" args="(const char *value, int index) const " --><div class="memitem"><div class="memproto"> <table class="memname"> <tr> <td class="memname"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> TiXmlHandle::Child </td> <td>(</td> <td class="paramtype">const char * </td> <td class="paramname"> <em>value</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">int </td> <td class="paramname"> <em>index</em></td><td> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td><td width="100%"> const</td> </tr> </table></div><div class="memdoc"><p>Return a handle to the "index" child with the given name. <p>The first child is 0, the second 1, etc. </div></div><p><a class="anchor" name="8786475b9d1f1518492e3a46704c7ef0"></a><!-- doxytag: member="TiXmlHandle::ChildElement" ref="8786475b9d1f1518492e3a46704c7ef0" args="(int index) const " --><div class="memitem"><div class="memproto"> <table class="memname"> <tr> <td class="memname"><a class="el" href="classTiXmlHandle.html">TiXmlHandle</a> TiXmlHandle::ChildElement </td> <td>(</td> <td class="paramtype">int </td> <td class="paramname"> <em>index</em> </td> <td> ) </td> <td width="100%"> const</td> </tr> </table></div><div class="memdoc">⌨️ 快捷键说明
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