libxml2的属性修改Ç [英] libxml2 attribute modification C

问题描述

我想在我的XML来改变一个属性（'压'）

  ...
    ＆LT;检测电压=1.2e3f/＆GT;
...
 

下面是我尝试如何做到这一点：

 无效save_detector_attr（*的xmlNode节点，xmlDoc中* DOC）{
        字符*电压;
        xmlAttrPtr s_vnewattr;
        CHAR BUF [128];
        *的xmlNode CUR =＆于节点GT; xmlChildrenNode;
        浮SV;
        INT CNT = 0;
        而（CUR！= NULL）{
            如果（当前＆GT;类型== XML_ELEMENT_NODE）{
                如果（xmlStrcmp（电流＆GT;！名字探测器））{
                    电压= xmlGetProp（CUR，电压）;
                    SV = ATOF（电压）;                    的snprintf（BUF，128，％F，SV + 20.1）;                    s_vnewattr = xmlNewProp（CUR，电压，BUF）;
                    的printf（保存到的电压值：％S \\ n，BUF）;                }
            }
            CUR =当前＆gt;接下来，
        }
        xmlSaveFor​​matFile（./mc2x.xml，DOC，1）;
 

不幸的是，而不是重写属性，调用函数时我在与这个新的文件后：

 ＆LT;检测电压=1.2e3f电压=1220.100000/＆GT;
 

如何使该属性将rewriten而不是创建一个新的？

问候
Ĵ

解决方案

只需使用 xmlSetProp ：

  xmlAttrPtr xmlSetProp（的xmlNodePtr节点，
                       常量XMLCHAR *名称，
                       常量XMLCHAR *值）
 

  

设置（或重置）由一个节点携带的属性。如果@name具有preFIX，则相应的空间结合将被使用，如果在范围;这是一个错误它有没有这样的NS-结合在范围preFIX。

I want to change one attribute ('voltage') in my xml:

...
    <detector voltage="1.2e3f"/>
...

Here is how im trying to do it:

 void save_detector_attr(xmlNode *node, xmlDoc *doc){
        char *voltage;
        xmlAttrPtr s_vnewattr;
        char buf[128];
        xmlNode *cur = node->xmlChildrenNode;
        float sv;
        int cnt = 0;
        while(cur != NULL) {
            if (cur->type == XML_ELEMENT_NODE) {
                if (!xmlStrcmp(cur->name, "detector")){
                    voltage = xmlGetProp(cur, "voltage");
                    sv = atof(voltage);

                    snprintf(buf, 128, "%f", sv + 20.1 );

                    s_vnewattr = xmlNewProp (cur, "voltage", buf);
                    printf(" SAVING to voltage value: %s\n", buf);

                }
            }
            cur = cur->next;
        }
        xmlSaveFormatFile ("./mc2x.xml", doc, 1);

unfortunately, instead of rewriting attribute, after that function is called i'm having a new file with this:

<detector voltage="1.2e3f" voltage="1220.100000"/>

How to make that attribute will be rewriten instead of creating a new one ?

regards J

解决方案

Simply use xmlSetProp:

xmlAttrPtr xmlSetProp (xmlNodePtr node, 
                       const xmlChar * name, 
                       const xmlChar * value)

Set (or reset) an attribute carried by a node. If @name has a prefix, then the corresponding namespace-binding will be used, if in scope; it is an error it there's no such ns-binding for the prefix in scope.

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