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xdocument re writing xml document [duplicate]

I have a method which load XML to a XDocument and modify its elements then save.
But when I reload it. I got this error :
Unexpected XML declaration. The XML declaration must be the first node in the document, and no white space characters are allowed to appear before it.
I checking the XML and see that the XDocument didn't save the changed but create a duplicate and save.
It save the old one and the new one like this example xml :
<?xml version="1.0" encoding="UTF-8"?>
<Ungdungs>
<Ungdung>
<Name>HERE City Lens</Name>
<Id>b0a0ac22-cf9e-45ba-8120-815450e2fd71</Id>
<Path>/Icon/herecitylens.png</Path>
<Version>Unknown</Version>
<Category>HERE</Category>
<Date>Uknown</Date>
</Ungdung>
<?xml version="1.0" encoding="UTF-8"?>
<Ungdungs>
<Ungdung>
<Name>HERE City Lens</Name>
<Id>b0a0ac22-cf9e-45ba-8120-815450e2fd71</Id>
<Path>/Icon/herecitylens.png</Path>
<Version>1.0.0.0</Version>
<Category>HERE</Category>
<Date>Uknown</Date>
</Ungdung>
Here the code I used to modify and save XML :
using (Stream stream = storage.OpenFile("APPSDATA.xml", FileMode.Open, FileAccess.ReadWrite))
{
//var xdoc = XDocument.Load("APPSDATA.xml");
var xdoc = XDocument.Load(stream, LoadOptions.None);
var listapp = from c in xdoc.Descendants("Ungdung") select c;
foreach (XElement app in listapp)
{
var xElement = app.Element("Name");
if (xElement != null)
progressIndicator.Text = "Checking " + xElement.Value + "...";
var element = app.Element("Id");
if (element != null)
{
var appId = element.Value;
var appVersion = await GetAppsVersion(appId);
app.Element("Version").Value = appVersion.ToString();
}
}
xdoc.Save(stream);
}
How can I solve this problem ?

Looks like you're appending modified document at the end of current file content. That's why you can't parse it later again.
I would split read and write parts into different using statements:
XDocument xdoc;
using (Stream stream = storage.OpenFile("APPSDATA.xml", FileMode.Open, FileAccess.Read))
{
xdoc = XDocument.Load(stream, LoadOptions.None);
}
var listapp = from c in xdoc.Descendants("Ungdung") select c;
foreach (XElement app in listapp)
{
var xElement = app.Element("Name");
if (xElement != null)
progressIndicator.Text = "Checking " + xElement.Value + "...";
var element = app.Element("Id");
if (element != null)
{
var appId = element.Value;
var appVersion = await GetAppsVersion(appId);
app.Element("Version").Value = appVersion.ToString();
}
}
using (Stream stream = storage.OpenFile("APPSDATA.xml", FileMode.Truncate, FileAccess.Write))
{
xdoc.Save(stream);
}
Setting FileMode.Truncate on second using statement will clear previous file content, what should fix your problem.

How to get attribute xml without loop c#

i have xml file like this
> <?xml version='1.0' ?>
<config>
<app>
<app version="1.1.0" />
> </app>
</config>
and i want to read attribute version from node app
without any loop like this
while(reader.read()) or foreach etc.
Thanks

XmlDocument document = new XmlDocument();
document.Load("D:/source.xml");
XmlNode appVersion1 = document.SelectSingleNode("//app[#version]/#version");
XmlNode appVersion2 = document["config"]["app"]["app"].Attributes["version"];
Console.WriteLine("{0}, {1}",
appVersion1.Value,
appVersion2.Value);

You can do it this way.
XmlDocument doc = new XmlDocument();
string str = "<config><app><app version=" + "\"1.1.0\"" + "/></app></config>";
doc.LoadXml(str);
var nodes = doc.GetElementsByTagName("app");
foreach (XmlNode node in nodes)
{
if (node.Attributes["version"] != null)
{
string version = node.Attributes["version"].Value;
}
}
And you need to this for loop cause you got two nodes with same name App.
If you have a single node with name App,
XmlDocument doc = new XmlDocument();
string str = "<config><app version=" + "\"1.1.0\"" + "/></config>";
doc.LoadXml(str);
var node = doc.SelectSingleNode("//app");
if (node.Attributes["version"] != null)
{
string version = node.Attributes["version"].Value;
Console.WriteLine(version);
}

You can use linq to do
string stringXml= "yourXml Here";
XElement xdoc = XElement.Parse(stringXml);
var result= xdoc.Descendants("app").FirstOrDefault(x=> x.Attribute("version") != null).attribute("version").Value;
or:
var result = xdoc.Descendants("app").Where(x => x.Attribute("version") != null)
.Select(x => new { Version = x.Value });

How To Remove Last Node In XML? C#

I am trying to remove the last node from an XML file, but cannot find any good answers for doing this. Here is my code:
XmlReader x = XmlReader.Create(this.PathToSpecialFolder + #"\" + Application.CompanyName + #"\" + Application.ProductName + #"\Recent.xml");
int c = 0;
while (x.Read())
{
if (x.NodeType == XmlNodeType.Element && x.Name == "Path")
{
c++;
if (c <= 10)
{
MenuItem m = new MenuItem() { Header = x.ReadInnerXml() };
m.Click += delegate
{
};
openRecentMenuItem.Items.Add(m);
}
}
}
x.Close();
My XML node structure is as follows...
<RecentFiles>
<File>
<Path>Text Path</Path>
</File>
</RecentFiles>
In my situation, there will be ten nodes maximum, and each time a new one is added, the last must be removed.

You can try this
XmlDocument doc = new XmlDocument();
doc.Load(fileName);
XmlNodeList nodes = doc.SelectNodes("/RecentFiles/File");
nodes[nodes.Count].ParentNode.RemoveChild(nodes[nodes.Count]);
doc.Save(fileName);

It sounds like you want something like:
var doc = XDocument.Load(path);
var lastFile = doc.Descendants("File").LastOrDefault();
if (lastFile != null)
{
lastFile.Remove();
}
// Now save doc or whatever you want to do with it...

Read the data from XML file into flat files(txt) and with formated data

I have an XML file with nodes and data...I need to write that into a text file as normal data. The nodes being the headers of the data
that follow.
EG XML:
<Bank>
<accountholder>Georgina Wax</accountholder>
<accountnumber>408999703657</accountnumber>
<accounttype>cheque</accounttype>
<bankname>National Bank</bankname>
<branch>Africa</branch>
<amount>2750.00</amount>
<date>12/01/2012</date>
</Bank>
To txt file and formatted as :
accountholder accountnumber accounttype bankname
Georgina Wax 408999703657 cheque National Bank
I can't seem to have it to have spaces between the data and hearders.
Below is what I tried :
StreamWriter writer = File.CreateText(#"C:\\Test.txt");
XmlDocument doc = new XmlDocument();
doc.Load(#"C:\\bank.xml");
writer.WriteLine(string.Join("|",doc.SelectSingleNode("/debitorders/deduction").ChildNodes.C ast<XmlElement>().Select(e => doc.SelectSingleNode("/debitorders/deduction/bankname").ToString())));
foreach (XmlElement book in doc.SelectNodes("/debitorders/deduction"))
{
writer.WriteLine(book.ChildNodes.Cast<XmlElement>().Select(e => e.InnerText).ToArray());
}
Please help.

This will produce output like you want.
private static void LoadAndWriteXML()
{
string headerFiles = "";
string values = "";
using (XmlReader reader = XmlReader.Create(#"C:\\bank.xml"))
{
while (reader.Read())
{
if (reader.NodeType == XmlNodeType.Element && !reader.Name.Equals("Bank")) // we have to skip root node means bank node.
{
headerFiles += reader.Name + " ";
values += reader.ReadString() + " ";
}
}
}
StreamWriter writer = new StreamWriter(#"C:\\Test.txt");
writer.WriteLine(headerFiles.Trim());
writer.WriteLine(values.Trim());
writer.Close();
}

XDocument xdoc = new XDocument();
xdoc = XDocument.Load(fname);
xdoc.Save(fname1);
will save the file with the tags alignment formating

Reading specific text from XML files

I have created a small XML tool which gives me count of specific XML tags from multiple XML files.
The code for this is as follow:
public void SearchMultipleTags()
{
if (txtSearchTag.Text != "")
{
try
{
//string str = null;
//XmlNodeList nodelist;
string folderPath = textBox2.Text;
DirectoryInfo di = new DirectoryInfo(folderPath);
FileInfo[] rgFiles = di.GetFiles("*.xml");
foreach (FileInfo fi in rgFiles)
{
int i = 0;
XmlDocument xmldoc = new XmlDocument();
xmldoc.Load(fi.FullName);
//rtbox2.Text = fi.FullName.ToString();
foreach (XmlNode node in xmldoc.GetElementsByTagName(txtSearchTag.Text))
{
i = i + 1;
//
}
if (i > 0)
{
rtbox2.Text += DateTime.Now + "\n" + fi.FullName + " \nInstance: " + i.ToString() + "\n\n";
}
else
{
//MessageBox.Show("No Markup Found.");
}
//rtbox2.Text += fi.FullName + "instances: " + str.ToString();
}
}
catch (Exception)
{
MessageBox.Show("Invalid Path or Empty File name field.");
}
}
else
{
MessageBox.Show("Dont leave field blanks.");
}
}
This code returns me the tag counts in Multiple XML files which user wants.
Now the same I want to Search for particular text and its count present in XML files.
Can you suggest the code using XML classes.
Thanks and Regards,
Mayur Alaspure

Use LINQ2XML instead..It's simple and a complete replacement to othe XML API's
XElement doc = XElement.Load(fi.FullName);
//count of specific XML tags
int XmlTagCount=doc.Descendants().Elements(txtSearchTag.Text).Count();
//count particular text
int particularTextCount=doc.Descendants().Elements().Where(x=>x.Value=="text2search").Count();

System.Xml.XPath.
Xpath supports counting: count(//nodeName)
If you want to count nodes with specific text, try count(//*[text()='Hello'])
See How to get count number of SelectedNode with XPath in C#?
By the way, your function should probably look something more like this:
private int SearchMultipleTags(string searchTerm, string folderPath) { ...
//...
return i;
}

Try using XPath:
//var document = new XmlDocument();
int count = 0;
var nodes = document.SelectNodes(String.Format(#"//*[text()='{0}']", searchTxt));
if (nodes != null)
count = nodes.Count;