想要使用c＃将特定节点保存到Xml文件中

Question

1. code below:

    protected void generate_Click(object sender, EventArgs e) { XmlDocument doc = new XmlDocument(); doc.PreserveWhitespace = true; doc.Load("XmlFileName"); XmlNode node = doc.SelectSingleNode("ChartData/XaxisFields/XaxisField"); if (node != null) { node.ChildNodes.Item(0).InnerXml = "hi"; doc.Save("XmlFileName"); } } 

2. Showing null refernce here,

    node.ChildNodes.Item(0).InnerXml = "hi"; 

3. Is the code is correct,the code behind running not showing any error but the Xaxisfield is not added.

    <?xml version="1.0" encoding="utf-8" ?> <ChartData> <XaxisFields> <XaxisField></XaxisField> </XaxisFields> </ChartData> 

4. List item

I want to add the childnode Xaxisfield in the xml file by selcting the particular parent node

Answer 1

You can use Linq to Xml to select your node and update its value:

var xdoc = XDocument.Load("XmlFileName");
xdoc.Root.Element("XaxisFields").Element("XaxisField").Value = "hi";
// OR
// xdoc.XPathSelectElement("//XaxisField").Value = "hi";
xdoc.Save("XmlFileName");

Also your code is not working because there is no child nodes of XaxisField node. This will work:

XmlDocument doc = new XmlDocument();
doc.PreserveWhitespace = true;
doc.Load("XmlFileName");
XmlNode node = doc.SelectSingleNode("ChartData/XaxisFields/XaxisField");
if (node != null)
{
    node.InnerXml = "hi";
    doc.Save("XmlFileName");
}