How to delete node from XML file using C# [duplicate]

Question

Possible Duplicate:
How to remove an XmlNode from XmlNodeList

Hi, How can i delete a set of nodes from an XML file.? Here is a code snippet.

string path = @"C:\Documents and Settings\e454935\Desktop\NUnitSettings.xml";
FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
System.Xml.XmlDocument xmldoc = new System.Xml.XmlDocument();
xmldoc.Load(fs);
fs.Close();
xmldoc.DocumentElement.RemoveChild(xmldoc.DocumentElement.ChildNodes[1]);
FileStream WRITER = new FileStream(path, FileMode.Truncate, FileAccess.Write, FileShare.ReadWrite);
xmldoc.Save(WRITER);
WRITER.Close();

I tried the following code simply to delete a node and got "Object reference not set to an instance of an object." at

xmldoc.DocumentElement.RemoveChild(xmldoc.DocumentElement.ChildNodes[1]);

Here is a sample XML file,

<?xml version="1.0"?>
<Xml1>
  <Settings>
    <Setting name="DisplayFormat" value="Full" />
    <Setting name="File1" value="a" />
    <Setting name="File1" value="b" />
    <Setting name="File1" value="c" />
    <Setting name="File1" value="d" />
  </Settings>
</Xml1>

Actually from this file i want to delete the Four File1 nodes which has the values "a,b,c,d" and then i want to add a node,

<Setting name="File1" value="e" />

How can i do this.?

This has been answered here stackoverflow.com/questions/875136 already, and probably two dozen times in other questions. Voted to close as a dupe. — Tomalak
– Tomalak, Commented May 28, 2009 at 7:48

idursun · Accepted Answer · 2009-05-28 07:52:23Z

31

You can use Linq to XML to do this:

XDocument doc = XDocument.Load("input.xml");
var q = from node in doc.Descendants("Setting")
        let attr = node.Attribute("name")
        where attr != null && attr.Value == "File1"
        select node;
q.ToList().ForEach(x => x.Remove());
doc.Save("output.xml");

answered May 28, 2009 at 7:52

idursun♦

6,3701 gold badge40 silver badges51 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

SyncMaster · Accepted Answer · 2009-05-28 10:07:29Z

15

Deleting nodes from XML

            XmlDocument doc = new XmlDocument();
            doc.Load(path);
            XmlNodeList nodes = doc.SelectNodes("//Setting[@name='File1']");
            for (int i = nodes.Count - 1; i >= 0; i--)
            {
                nodes[i].ParentNode.RemoveChild(nodes[i]);
            }
            doc.Save(path);

Adding attribute to Nodes in XML

    XmlDocument originalXml = new XmlDocument();
    originalXml.Load(path);
    XmlNode menu = originalXml.SelectSingleNode("//Settings");
    XmlNode newSub = originalXml.CreateNode(XmlNodeType.Element, "Setting", null);
    XmlAttribute xa = originalXml.CreateAttribute("name");
    xa.Value = "qwerty";
    XmlAttribute xb = originalXml.CreateAttribute("value");
    xb.Value = "555";
    newSub.Attributes.Append(xa);
    newSub.Attributes.Append(xb);
    menu.AppendChild(newSub);
    originalXml.Save(path);

answered May 28, 2009 at 10:07

SyncMaster

9,98635 gold badges105 silver badges144 bronze badges

1 Comment

Adam Plocher Over a year ago

Not sure why you were downvoted, but +1 from me. That node.ParentNode.RemoveChild(node) is a handy line of code to remember.

Community · Accepted Answer · 2017-05-23 11:46:55Z

8

It may be easier to use XPath to locate the nodes that you wish to delete. This stackoverflow thread might give you some ideas.

In your case you will find the four nodes that you want using this expression:

XmlDocument doc = new XmlDocument();
doc.Load(fileName);
XmlNodeList nodes = doc.SelectNodes("//Setting[@name='File1']");

edited May 23, 2017 at 11:46

CommunityBot

11 silver badge

answered May 28, 2009 at 7:46

Fredrik Mörk

159k31 gold badges296 silver badges349 bronze badges

Comments

Gonzalo.- · Accepted Answer · 2013-01-29 19:48:47Z

3

DocumentElement is the root node of the document so childNodes[1] doesn't exist in that document. childNodes[0] would be the <Settings> node

edited Jan 29, 2013 at 19:48

Gonzalo.-

12.7k5 gold badges53 silver badges84 bronze badges

answered May 28, 2009 at 7:44

PQW

1,1976 silver badges6 bronze badges

1 Comment

Tomalak Over a year ago

+1 for explaining where the error lies.

Collectives™ on Stack Overflow

How to delete node from XML file using C# [duplicate]

4 Answers 4

Comments

1 Comment

Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

1 Comment

Comments

1 Comment

Linked

Related