Selecting Nodes in xmldocument

Question

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);

Manas Mohapatra · Answer

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.

Bikesh Srivastava · Answer

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.