C＃在属性等于的地方添加xml元素

Question

I have an xml file that has a bunch of channels, and I want to append a channel category to every single one of them. Depending on what channel it is. I'm very new to this so please excuse me if this is an obvious error.

example:

<channel-category>Entertainment</channel-category>

or

<channel-category>News</channel-category>

I have tried the following:

        string path;
        string xmlfile = "/channels.xml";
        path = Environment.CurrentDirectory + xmlfile;

        if (exists("channelname1"))
        {
            XmlDocument doc = new XmlDocument();
            doc.Load(path);
            XmlNode root = doc.DocumentElement;
            XmlNode node = root.SelectSingleNode("list/channel[@id='channelname1'");
            XmlNode category = doc.CreateElement("channel-category");
            category.InnerText = "channelcataegorygoeshere";
            node.AppendChild(category);
            doc.DocumentElement.AppendChild(node);
        }
        else
        {
            Console.WriteLine("not found");
        }
        Console.ReadKey();
    }
    static bool exists(string channelname)
    {
        string path;
        string xmlfile = "/channels.xml";
        path = Environment.CurrentDirectory + xmlfile;
        XDocument xmlDoc = XDocument.Load(path);

        bool doesexists = (from data in xmlDoc.Element("list").Elements("channel")
                       where (string)data.Attribute("id") == channelname
                       select data).Any();
        return doesexists;
    }

but it's giving me the following error and I can't figure it out.. What am I doing wrong?

 An unhandled exception of type 'System.Xml.XPath.XPathException' occurred in System.Xml.dll
    Additional information: 'list/channel[@id='channelname1'' has an invalid token.

from this line

XmlNode node = root.SelectSingleNode("list/channel[@id='channelname1'");

My XML looks like this

<?xml version="1.0" encoding="UTF-8"?>
<list info="list">
  <channel id="channelname1">
    <display-name lang="en">channelname1</display-name>
    <icon src="http://locationtologo.com/" />
    <url>http://someurl.com</url>
  </channel>
  <channel id="channelname2">
    <display-name lang="en">channelname2</display-name>
    <icon src="http://locationtologo.com/" />
    <url>http://someurl.com</url>
  </channel>
  <channel id="channelname3">
    <display-name lang="en">channelname3</display-name>
    <icon src="http://locationtologo.com/" />
    <url>http://someurl.com</url>
  </channel>
  <channel id="channelname4">
    <display-name lang="en">channelname4</display-name>
    <icon src="http://locationtologo.com/" />
    <url>http://someurl.com</url>
  </channel>
</list>

Answer 1

You dont have closing bracket in list/channel[@id='channelname1'(HERE) .

Moreover, you are actually trying to do following:

var doc = new XmlDocument();
doc.Load(Environment.CurrentDirectory + "\\channels.xml");
var nodes = doc.SelectNodes("list/channel[@id=\"channelname1\"]");
if (nodes != null)
{
    foreach (XmlNode node in nodes)
    {
        var el = doc.CreateElement("channel-category");
        el.InnerText = "SomeValue";
        node.AppendChild(el);
    }
}

Answer 2

Why you are using tv instead of list thats why xml library not getting your path of your elements and throwing this error.

try this..

XmlNode node = root.SelectSingleNode("list/channel");
node.Attributes["id"].Value=="channelname1"?true:false;

Answer 3

    bool doesexists = (from data in xmlDoc.Element("tv").Elements("channel")
                   where (string)data.Attribute("id") == channelname
                   select data).Any();

You are trying to reach the channel node where the id equals the channelname inside tv . The problem is that tv does not exist, the channels are inside this:

<list info="list">

Solution: either put the channels into tv , or use a selector appropriate to your current structure.