'xsi'是使用XmlDocument的未声明的前缀

Question

我收到'xsi'是使用XmlDocument的未声明的前缀.

我正在尝试读取具有以下架构的文件:

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2"
     xmlns:gx="http://www.google.com/kml/ext/2.2" 
     xmlns:kml="http://www.opengis.net/kml/2.2"
     xmlns:atom="http://www.w3.org/2005/Atom">
        <Document>
            <Document id="robert" xsi:schemaLocation="http://www.opengis.net/kml/2.2 http://schemas.opengis.net/kml/2.2.0/ogckml22.xsd http://www.google.com/kml/ext/2.2 http://code.google.com/apis/kml/schema/kml22gx.xsd">
              <Placemark>
                <description>test</description>
              </Placemark>
        </Document>
    </Document>
</kml>

我尝试过以下方法:

    XmlDocument xmldoc = new XmlDocument();
    using (XmlTextReader tr = new XmlTextReader(strXmlFile))
    {
        //tr.Namespaces = false; (uncomment to ignore namespace)
        xmldoc.Load(tr);  // 'xsi' is an undeclared prefix error here
    }

如果我取消注释该行以忽略命名空间,它会加载正常但无法保存XmlDocument以后.所以忽略它不会是一个解决方案.有谁知道如何正确加载架构？问题/错误似乎在此节点中:

<Document id="robert" xsi:schemaLocation="http://www.opengis.net/kml/2.2 http://schemas.opengis.net/kml/2.2.0/ogckml22.xsd http://www.google.com/kml/ext/2.2 http://code.google.com/apis/kml/schema/kml22gx.xsd">

更新#1 我尝试了以下内容:

XmlDocument xmldoc = new XmlDocument();
NameTable nt = new NameTable();
XmlNamespaceManager nsmgr = new XmlNamespaceManager(nt);
nsmgr.AddNamespace("xsi", "http://www.w3.org/2001/XMLSchema-instance");
XmlParserContext context = new XmlParserContext(null, nsmgr, null, XmlSpace.None);
XmlReaderSettings xset = new XmlReaderSettings();
xset.ConformanceLevel = ConformanceLevel.Fragment;
XmlReader rd = XmlReader.Create(new StringReader(strXmlFile), xset, context);
xmldoc.Load(rd);  // error is still on this line

但是我现在收到这个错误:

"指定的节点不能作为此节点的有效子节点插入,因为指定的节点类型错误." 看起来我越来越近了......

Answer 1

解:

我能够解决问题!这是最终的代码:

XmlDocument xmldoc = new XmlDocument();
XmlReaderSettings settings = new XmlReaderSettings { NameTable = new NameTable() };
XmlNamespaceManager xmlns = new XmlNamespaceManager(settings.NameTable);
xmlns.AddNamespace("xsi", "http://www.w3.org/2001/XMLSchema-instance");
XmlParserContext context = new XmlParserContext(null, xmlns, "", XmlSpace.Default);
XmlReader reader = XmlReader.Create(strXmlFile, settings, context);
xmldoc.Load(reader);

还有一个提示,当搜索节点时,记得设置正确的命名空间,例如搜索上面的地标,这将是以下格式:

// Setup default namespace manager for searching through nodes
XmlNamespaceManager manager = new XmlNamespaceManager(xmldoc.NameTable);
string defaultns = xmldoc.DocumentElement.GetNamespaceOfPrefix("");
manager.AddNamespace("ns", defaultns);

// get a list of all <Placemark> nodes
XmlNodeList listOfPlacemark = xmldoc.SelectNodes("//ns:Placemark", manager);

// iterate over the <Placemark> nodes
foreach (XmlNode singlePlaceMark in listOfPlacemark)

// Get the description subnode
XmlNode descriptionNode = singlePlaceMark.SelectSingleNode("ns:description", manager);

..

Answer 2

您缺少xsi名称空间声明:

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

现在你的文档应该是这样的:

<kml xmlns="http://www.opengis.net/kml/2.2"
          xmlns:gx="http://www.google.com/kml/ext/2.2" 
          xmlns:kml="http://www.opengis.net/kml/2.2"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xmlns:atom="http://www.w3.org/2005/Atom">
.....
</kml>