从C＃中的SQLite数据库读取具有名称空间的xml数据

Question

I'm confronted with a XML structure from a SQLite database with two namespaces. How can I reference to 'floatnumber' (behind second ns) when no attribute name is present?

<?xml version="1.0" encoding="utf-8"?>
<anyType xmlns:q1="http://www.w3.org/2001/XMLSchema"
         d1p1:type="q1:string" 
         xmlns:d1p1="http://www.w3.org/2001/XMLSchema-instance">
   floatnumber
 </anyType>

Connecting with package v1.0.98.0 from https://system.data.sqlite.org/ to SQLite database was straight forward. I was playin around with XmlReader and XDocument (LINQ-to-XML) but no success.

What is the best way to read 'floatnumber' (database column 'Value') from xml in C# ?

using (SQLiteCommand sqlcmd = new SQLiteCommand())
{
    sqlcmd.Connection = connect;
    sqlcmd.CommandText = sqlquery;
    SQLiteDataReader rdr = null;
    try
    {
        rdr = sqlcmd.ExecuteReader(CommandBehavior.CloseConnection);
        while (rdr.Read())
        {
            string xmlstr = rdr["Value"].ToString();
            Console.WriteLine(xmlstr);                  // gives whole xml structure

            /* code to get floatnumber from xml */
        }
    }
    catch ()
    {}
}

My first post here. Tom

Answer 1

From the provided XML anyType does NOT have a namespace. It does define two namespaces q1 and d1p1 but they are not used to reference the element. The sample below uses an XPath expression to get the element. You could also use Linq to XML .

Using System.Xml;

var doc = new XmlDocument();
doc.LoadXml(xmlstr);
var floatnumber = doc.SelectSingleNode("anyType[content() = 'floatnumber']");

Update

string s = doc.SelectSingleNode("anyType").Value;
double d = XmlConvert.ToDouble(s);

Answer 2

Using XML Linq

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string xmlstr =
                "<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
                "<anyType xmlns:q1=\"http://www.w3.org/2001/XMLSchema\"" +
                      " d1p1:type=\"q1:string\"" +
                      " xmlns:d1p1=\"http://www.w3.org/2001/XMLSchema-instance\">" +
                      "floatnumber" +
               "</anyType>";

            XDocument doc = XDocument.Parse(xmlstr);
            XElement anyType = (XElement)doc.FirstNode;
            XNamespace ns = anyType.Name.Namespace;
            XNamespace q1 = anyType.Attributes().Where(x => x.Name.LocalName == "q1").FirstOrDefault().Name.Namespace;
            XNamespace type = anyType.Attributes().Where(x => x.Name.LocalName == "type").FirstOrDefault().Name.Namespace;
            XNamespace d1p1 = anyType.Attributes().Where(x => x.Name.LocalName == "d1p1").FirstOrDefault().Name.Namespace;

            string floatnumber = anyType.Value;

        }
    }
}​