C# read XML File and select Nodes

Question

i try to read from an XML file. the XML file is created whith the c# XmlSerializer.

the xml file Looks like

<command>
   <Name>one</Name>
   <data>
     <int>46</int>
     <int>49</int>
     <int>50</int>
   </data>
   <rangeData>
     <int>36</int>
     <int>29</int>
     <int>10</int>
   </rangeData>
</command>

to read the xml file i use the following code

string filename = "01.xml";
XmlDocument xdc = new xmlDocument();
xdc.Load(filename);
XmlNodeList xnlNodes = xelRoot.SelectNodes("command");

foreach(XMLNode nxmNode in xnlNodes)
{
  XmlElement element = (XmlElement)xndNode;

  string Name = Convert.ToString(xndNode{"Name"].InnerText);

   data = new int[]
   {
     Convert.ToInt32(element.GetElementsByTagName("int")[0].InnerText),
     Convert.ToInt32(element.GetElementsByTagName("int")[1].InnerText),
     Convert.ToInt32(element.GetElementsByTagName("int")[2].InnerText),
   };

   rangeData = new int[]
   {
     Convert.ToInt32(element.GetElementsByTagName("int")[0].InnerText),
     Convert.ToInt32(element.GetElementsByTagName("int")[1].InnerText),
     Convert.ToInt32(element.GetElementsByTagName("int")[2].InnerText),
   };
  }
}

my Problem is, that i do not know how to select the right child node. i hope that someone can help me please. thanks

Answer 1

Here's how to do it with your approach:

        string filename = "01.xml";
        XmlDocument xdc = new XmlDocument();
        xdc.Load(filename);
        XmlNodeList xnlNodes = xdc.SelectNodes("command");

        foreach (XmlNode xnlNode in xnlNodes)
        {
            XmlElement element = (XmlElement)xnlNode;

            string Name = Convert.ToString(xnlNode["Name"].InnerText);
            int[] data = new int[]
                {
 Convert.ToInt32(element.GetElementsByTagName("data")[0].ChildNodes[0].InnerText),
 Convert.ToInt32(element.GetElementsByTagName("data")[0].ChildNodes[1].InnerText),
 Convert.ToInt32(element.GetElementsByTagName("data")[0].ChildNodes[2].InnerText)
                };

            int[] rangeData = new int[]
                {
 Convert.ToInt32(element.GetElementsByTagName("rangeData")[0].ChildNodes[0].InnerText),
 Convert.ToInt32(element.GetElementsByTagName("rangeData")[0].ChildNodes[1].InnerText),
 Convert.ToInt32(element.GetElementsByTagName("rangeData")[0].ChildNodes[2].InnerText)
                };
        }

Answer 2

I suggest to use LINQ for reading XML:

var xdoc = XDocument.Load(filename);
var cmd = xdoc.Root;
var command = new {
   Name = (string)cmd.Element("Name"),
   Data = cmd.Element("data").Elements().Select(e => (int)e).ToList(),
   RangeData = cmd.Element("rangeData").Elements().Select(e => (int)e).ToList()
};

Output:

{
  Name: "one",
  Data: [ 46, 49, 50 ],
  RangeData: [ 36, 29, 10 ]
}

if you didn't provide whole xml, but only part of it and actually you have many commands, then parsing will look like

var commands =
      from cmd in xdoc.Descendands("command")
      select new {
         Name = (string)cmd.Element("Name"),
         Data = cmd.Element("data").Elements().Select(e => (int)e).ToList(),
         RangeData = cmd.Element("rangeData").Elements().Select(e => (int)e).ToList()
      }

Answer 3

Here's an example how to access nodes using xpath

    XmlDocument xdc = new XmlDocument();
    xdc.Load(filename);
    var nodes = xdc.SelectNodes("command/data/int");
    foreach (XmlNode node in nodes)
    {
        string s = node.InnerText;
    }

To learn more about XPath, check this tutorial

Answer 4

you can use XPath here

void Main()
{
    var doc = new XmlDocument();
    doc.LoadXml(xml);   

    var name = doc.DocumentElement
        .SelectSingleNode("/command/Name")
        .InnerText;

    var data = doc.DocumentElement
        .SelectNodes("/command/data/int")
        .OfType<XmlNode>()
        .Select(x=> Int32.Parse(x.InnerText))
        .ToArray(); 

    var rangeData = doc.DocumentElement
        .SelectNodes("/command/rangeData/int")
        .OfType<XmlNode>()
        .Select(x => Int32.Parse(x.InnerText))
        .ToArray();
}


string xml = @"
<command>
   <Name>one</Name>
   <data>
     <int>46</int>
     <int>49</int>
     <int>50</int>
   </data>
   <rangeData>
     <int>36</int>
     <int>29</int>
     <int>10</int>
   </rangeData>
</command>
";