Selecting Nodes in xmldocument

sandra abo

10y1.2k

I am trying to call webservice and when hit search button to return value, the page throw error. I'm trying to parse data from calling API using xpath;

Code:

protected string getattributevalue(string id, XmlDocument doc)
{
// Load the document and set the root element.
XmlNode root = doc.DocumentElement;
// Add the namespace.
XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
nsmgr.AddNamespace("go", "http://b.myserver.com/student/sign.xsd");
String result;
// Select and display the first node in which the author's
try
{
XmlNodeList nodelist = root.SelectNodes("//signup", nsmgr);
// Console.WriteLine(node.InnerXml);
result = nodelist.Count.ToString();
}
catch (XPathException ex)
{
Console.Write(ex.ToString());
result = "Error: " + ex.ToString();
}
catch (NullReferenceException ex)
{
Console.Write(ex.ToString());
result = "Error: " + ex.ToString();
}
return result;
}

Error: System.NullReferenceException: Object reference not set to an instance of an object. at WebReg._Default.getattributevalue(String id, XmlDocument doc) in Default.aspx.cs:line 55 XmlNodeList nodelist = root.SelectNodes("//signup", nsmgr);

2 Replies

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Manas Mohapatra10y ago
Below code may help you:
XmlDocument doc = new XmlDocument();
doc.LoadXml("" +
            "" +
            "Pride And Prejudice" +
            "");

//Display the document element.
Console.WriteLine(doc.DocumentElement.OuterXml);

XmlDocument xml = new XmlDocument();
xml.LoadXml(str);  // suppose that str string contains "..."

// Add the namespace.
XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
nsmgr.AddNamespace("go", "http://b.myserver.com/student/sign.xsd");

XmlNodeList nodelist = xml.SelectNodes("/signup", nsmgr);
String result = nodelist.Count.ToString();
Note: You may need to change XML data whatever you are getting from webservice. Make sure that XML data is correct in syntax.
0
Bikesh Srivastava10y ago
use code like this .
XmlNode node = doc.SelectSingleNode("//DGField[@text_id='Test.ChangeRank']");
  if (node != null)
  {
    node.Attributes["visible"].Value = "false";
  }
Mark as answer if solve your query.
0