使用C＃选择所有在XML中具有名称空间的节点

Question

Hi can anybody help me out. I have a XML which contains my own namespace xmlns:NS . I need to select all the nodes which contains the namespace "NS". How can we do this using C#.net.

I tried like below:

XmlDocument doc=new XmlDocument();
doc.Load(Path);
XmlNodeList oNodeList=doc.GetElementByTagname("NS:Text");

Here i am getting all the nodes which have "NS:Text" namespace. But I need to select all the nodes like below:

XmlDocument doc=new XmlDocument();
doc.Load(Path);
XmlNodeList oNodeList=doc.GetElementByTagname("NS");

so that i can select all the nodes which contains namespace "NS". but this is not working. How can we achieve this?

Following is my XML format.

<xml 1.0 ?>
    <Root xmlns:NS="www.yembi.com">
        <NS:Entry Value="User">
            <table>
                <tr>
                    <td>
                        <NS:display type="Label" name="First Name">
                    </td>
                </tr>
                <tr>
                    <td>
                        <NS:Text type="Text">
                    </td>
                </tr>
                <tr>
                    <td>
                        <NS:Button Type="SubmitButton" name="submit">
                    </td>
                </tr>
            </table>
        </NS:Entry>

Answer 1

I'd like to suggest LINQ to XML if you've .net framework version 3.5 or higher.

    XDocument doc = XDocument.Load(Path);

    XNamespace ns = "www.yembi.com";
    var result = doc.Root.Descendants()
                   .Where(p => p.GetPrefixOfNamespace(ns) == "NS");

Answer 2

You can use an XPath expression with the SelectNodes method .

XmlDocument doc = new XmlDocument();
doc.Load(Path);

XmlNamespaceManager mgr = new XmlNamespaceManager(doc.NameTable);
mgr.AddNamespace("NS", "www.yembi.com");
XmlNodeList oNodeList = doc.SelectNodes("//NS:*", mgr);

The XPath expression //NS:* selects any element with the NS prefix.

One note on your question: NS is not a namespace in your Xml document, it is just a namespace prefix. www.yembi.com is your namespace.

You can think of the prefix as a local (within the document) placeholder for the namespace that connects the namespace with the identifiers in the document. You can easily change the placeholder in the XPath-related code (eg to x ), and leave the NS in the document, and things will still work, as long as it's still the namespace www.yembi.com .