Edit XML node in c#

Question

I'm trying to edit a node in .xml file but i can't get it working.

My XML:

<configuration>
  <car title="Ferrari">
    <url>http://www.ferrari.com</url>
  </car>
</configuration>

My code in c#:

    string var_x = "Ferrari";
    XmlDocument doc = new XmlDocument();
    doc.Load("Config.xml");
    XmlNode itemTitle = doc.SelectSingleNode("/configuration/car[@title = '" + var_x + "']");
    XmlNode itemUrl = doc.SelectSingleNode("/configuration/car[@title = '" + var_x + "']/url");


    itemTitle.InnerText = texbox_title.Text;
    itemUrl.InnerText = textbox_url.Text;

    doc.Save("Config.xml");

I can't get code above working for my xml. I can't edit that node. Maybe a problem with XPath but i can't figure out why it's not working properly.

My XML after using c# code above:

<configuration>
  <car title="Ferrari">NEW_NAME</car>
</configuration>

Answer 1

As you want to change the value of the attribute title of the car element, change your code as follows:

 XmlElement itemTitle = (XmlElement)doc.SelectSingleNode("/configuration/car[@title = '" + var_x + "']");
 XmlNode itemUrl = doc.SelectSingleNode("/configuration/car[@title = '" + var_x + "']/url");

 itemTitle.Attributes["title"].Value = texbox_title.Text;
 itemUrl.InnerText = textbox_url.Text;

In your version, the complete inner text of the car element (including the url sub-element) is overwritten by the car title.
In addition, you need to cast the result of SelectSingleNode to XmlElement as this has the Attributes collection.

Answer 2

The property InnerText refers to everything which is text, so you are replacing the content of the car element, including the url element with the line:

itemTitle.InnerText = texbox_title.Text;

Use the following instead:

itemTitle.Attributes["title"].Value = texbox_title.Text;
itemUrl.InnerText = textbox_url.Text;