Overwrite a xml file value

问题

I have a xml file like this

<count>0</count>

Now I wish to overwrite the value 0. How do I do that in c#?

EDIT

<counter>
  <count>0</count>
  <email>
  </email>
</counter>`

This is my XML file I wish to write a value in the email element and also change the value of count element

            XmlDocument doc = new XmlDocument();
            doc.Load(COUNTER);
            foreach (XmlNode node in doc.SelectNodes("count"))
            {
                node.InnerText = (count-1).ToString();
            }
            foreach (XmlNode node in doc.SelectNodes("email"))
            {
                node.InnerText = (count - 1).ToString();
            }
            doc.Save(COUNTER); `

When I do this no values are written to the file

回答1:

Your direct problem is the use of doc.SelectNodes("count") instead of doc.GetElementsByTagName("count")

回答2:

You're not showing us the entire XML, so we cannot really tell you in detail how to do it.

Basically, if your XML file is fairly small, you can load it into an XmlDocument and then search for that <child> node using an XPath expression, and then replace that node's value.

Something like:

// create your XmlDocument
XmlDocument doc = new XmlDocument();

// load the XML from a file on disk - ADAPT to your situation!
doc.Load(@"C:\test.xml");

// search for a node <count>
XmlNode countNode = doc.SelectSingleNode("/counter/count");

// if node is found
if(countNode != null)
{
    // update the node's .InnerText value (the "contents" of the node)    
    countNode.InnerText = "42";

}

// search for a node <email>
XmlNode emailNode = doc.SelectSingleNode("/counter/email");

// if node is found
if(emailNode != null)
{
    // update the node's .InnerText value (the "contents" of the node)    
    emailNode.InnerText = "bob@microsoft.com";
}

// save XmlDocument out to disk again, with the change
doc.Save(@"C:\test_new.xml");

回答3:

You can read the file in C# using C# XML Classes change the value and then write it back to the file.

You can use ReplaceChild Method for that.

for more info read on XmlDocument and see this Microsoft Example

回答4:

Using Linq to Xml:

XElement x = XElement.Parse("<myDocument><code>0</code></myDocument>");
x.Descendants().Where(n=>n.Name.LocalName.Equals("code")).ToList().ForEach(n=>n.SetValue("1"));

LINQPad is a great tool for experimenting with this.

来源：https://stackoverflow.com/questions/4948027/overwrite-a-xml-file-value

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xml

overwrite