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Can not read values/nodes from xml using c#

I'm trying to read values from following xml (which is previously fetched from FTP):
<?xml version="1.0" encoding="utf-8"?>
<eventdata xmlns="http://www.demoweb.net/xml/eventdata" >
<site>
<sitelink>demotesting</sitelink>
<user>15101991</user>
<measurement>
<nodelink>012019120312064500</nodelink>
<containername>A1</containername>
<time>2020-04-30T11:25:35</time>
<value type="n_v_unitvalue">0.04</value>
<value type="n_v_unitvalue_diff">0.040</value>
</measurement>
<measurement>
<nodelink>012019120312064501</nodelink>
<containername>A2</containername>
<time>2020-04-30T11:25:35</time>
<value type="n_v_unitvalue">0.0</value>
<value type="n_v_unitvalue_diff">-0.001</value>
</measurement>
<measurement>
<nodelink>012019120312064502</nodelink>
<containername>A3</containername>
<time>2020-04-30T11:25:34</time>
<value type="n_v_unitvalue">0.0</value>
<value type="n_v_unitvalue_diff">0.000</value>
</measurement>
</site>
<createdate>2020-04-30T11:25:35</createdate>
</eventdata>
Before I start, file is sucessfully loaded into memory :)
As you can see root node is eventdata, and site is the node where all data is contained.
So basically I need to loop all measurement nodes and get the data.
I also were struggling to get out user node.. here's what I've tried so far:
using (StreamReader xml_reader = new StreamReader(xml_response.GetResponseStream()))
{
string xml = xml_reader.ReadToEnd();
XmlDocument xmldoc = new XmlDocument();
xmldoc.LoadXml(xml);
XmlNodeList mainFileContent = xmldoc.SelectNodes("eventdata");
// XmlNodeList mainFileContent = xmldoc.SelectNodes("eventdata/site");
XmlElement root = xmldoc.DocumentElement;
if (mainFileContent != null)
{
foreach (XmlNode node in mainFileContent)
{
var user = node["user"].InnerText;
}
}
}
What I'm missing?
THANKS GUYS
CHEERS

Your eventdata node has own xmlns declaration, you should properly handle it using XmlNamespaceManager and select the nodes with x:eventdata/x:site XPath expression
var xmldoc = new XmlDocument();
xmldoc.LoadXml(xml);
var nsmgr = new XmlNamespaceManager(xmldoc.NameTable);
nsmgr.AddNamespace("x", xmldoc.DocumentElement.NamespaceURI);
var mainFileContent = xmldoc.SelectNodes("x:eventdata/x:site", nsmgr);
foreach (XmlNode node in mainFileContent)
{
var user = node["user"]?.InnerText;
}

Use below code to read measurement
using (StreamReader xml_reader = new StreamReader(xml_response.GetResponseStream()))
{
string xml = xml_reader.ReadToEnd();
XmlDocument xmldoc = new XmlDocument();
xmldoc.LoadXml(xml);
var nsmgr = new XmlNamespaceManager(xmldoc.NameTable);
nsmgr.AddNamespace("ns", "http://www.demoweb.net/xml/eventdata");
XmlNodeList mainFileContent = xmldoc.SelectNodes("ns:eventdata/ns:site",nsmgr);
XmlElement root = xmldoc.DocumentElement;
if (mainFileContent != null)
{
foreach (XmlNode site in mainFileContent)
{
var user = site["user"].InnerText;
XmlNodeList measurements = site.SelectNodes("ns:measurement", nsmgr);
if (measurements != null)
{
foreach (XmlNode measurement in measurements)
{
var containername = measurement["containername"].InnerText;
var time = measurement["time"].InnerText;
XmlNodeList values = measurement.SelectNodes("ns:value", nsmgr);
if (values != null)
{
foreach (XmlNode value in values)
{
var type = value.Attributes["type"].Value;
var v2 = value.InnerText;
}
}
}
}
}
}
}

How to update xml file without using Linq?

I have this xml file:
<students>
<student>
<name>Mark</name>
<age>20</age>
</student>
<student>
<name>Adam</name>
<age>32</age>
</student>
I want to change the age of Adam, for that I did:
XmlDocument doc = new XmlDocument();
doc.Load("/path/to/sutdents.xml");
XmlNode n = doc.SelectSingleNode("/students/student[name='" + student.name +
"']");
if (n != null)
{
n.SelectNodes("age").Item(0).FirstChild.Value = new_value;
}
but I get "n" as a null value.
I tried another way to do that by searching for the node using foreach and make change, but I get Null Exception:
XmlDocument doc = new XmlDocument();
doc.Load("/path/to/sutdents.xml");
XmlNodeList nodes = doc.SelectNodes("/students/student");
foreach (XmlNode node in nodes)
{
if (node.FirstChild.InnerText == student.name)
{
node.SelectSingleNode("age").InnerText = new_value;
}
}
what I missing here please?
Thanks in advance

I tried to run your code. that is work! check what is the value of student.name.
XML [sutdents.xml]
<?xml version="1.0" standalone="yes"?>
<students>
<student>
<name>Mark</name>
<age>20</age>
</student>
<student>
<name>Adam</name>
<age>32</age>
</student>
</students>
sample code:
XmlDocument doc = new XmlDocument();
doc.Load("sutdents.xml");
XmlNode n = doc.SelectSingleNode("/students/student[name='Adam']");
if (n != null)
{
n.SelectNodes("age").Item(0).FirstChild.Value = "44";
}
doc.Save("sutdents.xml");

i hope this helps;
When Using foreach:
XmlNodeList studentsList = doc.ChildNodes[0].SelectNodes("student");
foreach (XmlNode node in studentsList)
{
if (node.ChildNodes[0].InnerText == student.name) //name
{
node.ChildNodes[1].InnerText = new_value; //age
}
}

Your Code is Correct here is a screen shot of your debugged code with same xml and mentioned code, check you are passing student.name with correct value and case sensitive.

Try this using XDocument:
private static void UpdateXML(string xmlpath, string studentName, int age)
{
var doc = XDocument.Load(xmlpath);
//Get student
var student = doc.Descendants("student").Where(att => att.Element("name") != null && att.Element("name").Value.Equals(studentName)).FirstOrDefault();
if (student != null)
student.Element("age").Value = age.ToString();
doc.Save(xmlpath);
}

XML represantation of treeview nodes

I am trying to import and export to treeview from XML file. But i am having this issue. sample treeview have one root node and two child nodes of same parent. The codes i am using for exporting and importing doesn't work. When I export the treeview the saved XML file is like this:
<?xml version="1.0" encoding="utf-8" ?>
<AAA>
BBBCCC</AAA>
When I import that xml file to treeview it look like this after import xml to treeview . Codes that i am using for export and import are:
//Open the XML file, and start to populate the treeview
private void populateTreeview()
{
OpenFileDialog dlg = new OpenFileDialog();
dlg.Title = "Open XML Document";
dlg.Filter = "XML Files (*.xml)|*.xml";
dlg.FileName = Application.StartupPath + "\\..\\..\\example.xml";
if (dlg.ShowDialog() == DialogResult.OK)
{
try
{
//Just a good practice -- change the cursor to a
//wait cursor while the nodes populate
this.Cursor = Cursors.WaitCursor;
//First, we'll load the Xml document
XmlDocument xDoc = new XmlDocument();
xDoc.Load(dlg.FileName);
// Now, clear out the treeview,
// and add the first (root) node
treeView1.Nodes.Clear();
treeView1.Nodes.Add(new TreeNode(xDoc.DocumentElement.Name));
TreeNode tNode = new TreeNode();
tNode = (TreeNode)treeView1.Nodes[0];
// We make a call to addTreeNode,
// where we'll add all of our nodes
addTreeNode(xDoc.DocumentElement, tNode);
// Expand the treeview to show all nodes
treeView1.ExpandAll();
}
catch(XmlException xExc)
{
// Exception is thrown is there is an error in the Xml
MessageBox.Show(xExc.Message);
}
catch(Exception ex) //General exception
{
MessageBox.Show(ex.Message);
}
finally
{
this.Cursor = Cursors.Default; //Change the cursor back
}
}
}
// This function is called recursively until all nodes are loaded
private void addTreeNode(XmlNode xmlNode, TreeNode treeNode)
{
XmlNode xNode;
TreeNode tNode;
XmlNodeList xNodeList;
if (xmlNode.HasChildNodes) // The current node has children
{
xNodeList = xmlNode.ChildNodes;
for(int x = 0; x <= xNodeList.Count - 1; x++)
{
// Loop through the child nodes
xNode = xmlNode.ChildNodes[x];
treeNode.Nodes.Add(new TreeNode(xNode.Name));
tNode = treeNode.Nodes[x];
addTreeNode(xNode, tNode);
}
}
else //No children, so add the outer xml (trimming off whitespace)
treeNode.Text = xmlNode.OuterXml.Trim();
}
private XmlTextWriter xr;
public void exportToXml2(TreeView tv, string filename)
{
xr = new XmlTextWriter(filename, System.Text.Encoding.UTF8);
xr.WriteStartDocument();
//Write our root node
xr.WriteStartElement(treeView1.Nodes[0].Text);
foreach (TreeNode node in tv.Nodes)
{
saveNode2(node.Nodes);
}
//Close the root node
xr.WriteEndElement();
xr.Close();
}
private void saveNode2(TreeNodeCollection tnc)
{
foreach (TreeNode node in tnc)
{
// If we have child nodes, we'll write
// a parent node, then iterate over
// the children
if (node.Nodes.Count > 0)
{
xr.WriteStartElement(node.Text);
saveNode2(node.Nodes);
xr.WriteEndElement();
}
else //No child nodes, so we just write the text
{
xr.WriteString(node.Text);
}
}
}
Where is the problem?

You are using language other than English . please convert and save .
var text = File.ReadAllText(file, Encoding.GetEncoding(codePage));
how-to-read-text-files-with-ansi-encoding-and-non-english-letters
File.WriteAllText(filepath, filetext, Encoding.Unicode);
or
new System.IO.StreamWriter(new FileStream(file_name,FileMode.OpenOrCreate),Encoding.ASCII);
read-write-text-file-ansi-utf8-unicode
how-to-convert-utf7-string-into-ansi-in-csharp

The code is fine. The xml should look like this
<?xml version="1.0" encoding="utf-8" ?>
<AAA>
<BBB/>
<CCC/>
</AAA>

ok, I modified a few lines and I managed what i want to.
Firstly, I add char array for special characters. And use them for trim() function.
private void addTreeNode(XmlNode xmlNode, TreeNode treeNode)
{
**char[] karakter = new char[] { '<', '>', '/' };**
XmlNode xNode;
TreeNode tNode;
XmlNodeList xNodeList;
if (xmlNode.HasChildNodes) //The current node has children
{
xNodeList = xmlNode.ChildNodes;
for (int x = 0; x <= xNodeList.Count - 1; x++)
{
xNode = xmlNode.ChildNodes[x];
treeNode.Nodes.Add(new TreeNode(xNode.Name));
tNode = treeNode.Nodes[x];
addTreeNode(xNode, tNode);
}
}
else
{
treeNode.Text = xmlNode.OuterXml.Trim(**karakter**);
}
secondly, if there is no child nodes I used WriteRaw method instead of WriteString method.Because special characters are replaced by WriteString method.
private void saveNode2(TreeNodeCollection tnc)
{
foreach (TreeNode node in tnc)
{
if (node.Nodes.Count > 0)
{
xr.WriteStartElement(node.Text);
saveNode2(node.Nodes);
xr.WriteEndElement();
}
else
{
**xr.WriteRaw($"<{node.Text}/>");**
}
}
But when I try to save treeview with two roots, It doesn't write the last root. Any opinion? Childs of last root is written as childs of first root. Other then that codes work.

How to delete selected node from XML in C#?

I am New To C# I have problem...
I want to delete selected node from My XMl File
Here I just tried with this code but I didn't get please can any one help in that
private void btnDelete_Click(object sender, EventArgs e)
{
xdoc.Load(strFilename);
string Xpath = string.Format("root/{0}/{1}",_strProCat,_strProdType);
xdoc.SelectSingleNode(Xpath).RemoveAll();
xdoc.Save(strFilename);
MessageBox.Show("Deleted Successfully");
}
Here My Xml File
<root>
<product category="Soaps">
<product type="Washing">
<product name="Rin">
<Id>100</Id>
<AvailProducts>30</AvailProducts>
<Cost>20.00</Cost>
</product>
<product name="Tide">
<Id>101</Id>
<AvailProducts>30</AvailProducts>
<Cost>15.00</Cost>
</product>
</product>
</product>
</root>
Just I want to delete Node which product name="Tide"

You can simple use the below code:
private void btnDelete_Click(object sender, EventArgs e)
{
var xDoc = XDocument.Load(strFilename);
foreach (var elem in xDoc.Document.Descendants("product"))
{
foreach (var attr in elem.Attributes("name"))
{
if (attr.Value.Equals("Tide"))
elem.RemoveAll();
}
}
xDoc.Save(destinationFilename);
MessageBox.Show("Deleted Successfully");
}
Happy Coding...

Something like this should do it:
xdoc.Elements("product").Where(x=> x.Element("name").Value == "Tide").FirstOrDefault().Remove();

If you want XPath with XmlDocument then following is the way to do it..
XmlDocument xdoc = new XmlDocument();
xdoc.Load(strFilename);
string Xpath = string.Format("root/product[#category='{0}']/product[#type='{1}']/product[#name='{2}']", "Soaps", "Washing", "Tide");
xdoc.SelectSingleNode(Xpath).RemoveAll();
xdoc.Save(strFilename);
Update
As per your Requirement To Remove the empty node, try following code to remove empty node as
XmlNodeList emptyElements = xdoc.SelectNodes(#"//*[not(node())]");
for (int i = emptyElements.Count - 1; i > -1; i--)
{
XmlNode nodeToBeRemoved = emptyElements[i];
nodeToBeRemoved.ParentNode.RemoveChild(nodeToBeRemoved);
}
Now your final full flesh code will look like as
string Xpath = string.Format("root/product[#category='{0}']/product[#type='{1}']/product[#name='{2}']", "Soaps", "Washing", "Tide");
xdoc.SelectSingleNode(Xpath).RemoveAll();
XmlNodeList emptyElements = xdoc.SelectNodes(#"//*[not(node())]");
for (int i = emptyElements.Count - 1; i > -1; i--)
{
XmlNode nodeToBeRemoved = emptyElements[i];
nodeToBeRemoved.ParentNode.RemoveChild(nodeToBeRemoved);
}
xdoc.Save(strFilename);

populate a tree view with an xml file

Im using .net windows form application. I have an xml file.I want to populate a tree view with data from a xml file. I am doing this using the following code.
private void button1_Click(object sender, EventArgs e)
{
try
{
this.Cursor = System.Windows.Forms.Cursors.WaitCursor;
//string strXPath = "languages";
string strRootNode = "Treeview Sample";
OpenFileDialog Dlg = new OpenFileDialog();
Dlg.Filter = "All files(*.*)|*.*|xml file (*.xml)|*.txt";
Dlg.CheckFileExists = true;
string xmlfilename = "";
if (Dlg.ShowDialog() == DialogResult.OK)
{
xmlfilename = Dlg.FileName;
}
// Load the XML file.
//XmlDocument dom = new XmlDocument();
//dom.Load(xmlfilename);
XmlDocument doc = new XmlDocument();
doc.Load(xmlfilename);
string rootName = doc.SelectSingleNode("/*").Name;
textBox4.Text = rootName.ToString();
//XmlNode root = dom.LastChild;
//textBox4.Text = root.Name.ToString();
// Load the XML into the TreeView.
this.treeView1.Nodes.Clear();
this.treeView1.Nodes.Add(new TreeNode(strRootNode));
TreeNode tNode = new TreeNode();
tNode = this.treeView1.Nodes[0];
XmlNodeList oNodes = doc.SelectNodes(textBox4.Text);
XmlNode xNode = oNodes.Item(0).ParentNode;
AddNode(ref xNode, ref tNode);
this.treeView1.CollapseAll();
this.treeView1.Nodes[0].Expand();
this.Cursor = System.Windows.Forms.Cursors.Default;
}
catch (Exception ex)
{
this.Cursor = System.Windows.Forms.Cursors.Default;
MessageBox.Show(ex.Message, "Error");
}
}
private void AddNode(ref XmlNode inXmlNode, ref TreeNode inTreeNode)
{
// Recursive routine to walk the XML DOM and add its nodes to a TreeView.
XmlNode xNode;
TreeNode tNode;
XmlNodeList nodeList;
int i;
// Loop through the XML nodes until the leaf is reached.
// Add the nodes to the TreeView during the looping process.
if (inXmlNode.HasChildNodes)
{
nodeList = inXmlNode.ChildNodes;
for (i = 0; i <= nodeList.Count - 1; i++)
{
xNode = inXmlNode.ChildNodes[i];
inTreeNode.Nodes.Add(new TreeNode(xNode.Name));
tNode = inTreeNode.Nodes[i];
AddNode(ref xNode, ref tNode);
}
}
else
{
inTreeNode.Text = inXmlNode.OuterXml.Trim();
}
}
My xml file is this:"hello.xml"
<?xml version="1.0" encoding="utf-8" ?>
<languages>
<language>
<key>abc</key>
<value>hello how ru</value>
</language>
<language>
<key>def</key>
<value>i m fine</value>
</language>
<language>
<key>ghi</key>
<value>how abt u</value>
</language>
</languages>
Now after using the above code I am able to populate the tree view. But I dont like to populate the complete xml file. I should get only till
languages
language
key
value
I don't want
abc
how are you
etc.....
I mean to say the leaf nodes. Please help me

What you don't want to add is the text content of the nodes, if I understood correctly; then, you might check the NodeType property of the XmlNode class, something like:
xNode = inXmlNode.ChildNodes[i];
if (xNode.NodeType != XmlNodeType.Text) {
inTreeNode.Nodes.Add(new TreeNode(xNode.Name));
tNode = inTreeNode.Nodes[i];
AddNode(ref xNode, ref tNode);
}