Null reference exception in xml - C#

Question

I am trying to get the country, lat/long, timezone etc from an api using public ip.

Below is the xml response i am getting from api,

<IPInformation xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://ws.cdyne.com/">
<City>Chennai</City>
<StateProvince>25</StateProvince>
<Country>India</Country>
<Organization/>
<Latitude>13.0833</Latitude>
<Longitude>80.28329</Longitude>
<AreaCode>0</AreaCode>
<TimeZone/>
<HasDaylightSavings>false</HasDaylightSavings>
<Certainty>90</Certainty>
<RegionName/>
<CountryCode>IN</CountryCode>
</IPInformation>

I am loading the response in xml file, from there using SelectSingleNode i am trying to get the country value. But always i am getting nullreferenceexception.

Below is the code i have tried,

if (response.StatusCode.ToString().ToLower() == "ok")
{
    XmlDocument xmlDoc = new XmlDocument();
    xmlDoc.Load(response.GetResponseStream());
    XmlNode msgnode = xmlDoc.DocumentElement.SelectSingleNode("//Country"); -->getting null here
    string msgname = msgnode.InnerText;                                      
}

tried below one,

String country = xmlDoc.SelectSingleNode("IPInformation/Country").Value;

SelectSingleNode always return a null value

Full stactrace:

at SingleScanPalletTag.MobileClient.ScanOutMenu.GetGeoLocation()
   at SingleScanPalletTag.MobileClient.ScanOutMenu.button1_Click(Object sender, EventArgs e)
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnClick(EventArgs e)
   at System.Windows.Forms.ButtonBase.WnProc(WM wm, Int32 wParam, Int32 lParam)
   at System.Windows.Forms.Control._InternalWnProc(WM wm, Int32 wParam, Int32 lParam)
   at Microsoft.AGL.Forms.EVL.EnterModalDialog(IntPtr hwnModal)
   at System.Windows.Forms.Form.ShowDialog()
   at SingleScanPalletTag.MobileClient.Program.Main()

Can any one tell me how to get the country,latitude and longitude value from the above xml.

Please help me.

It's unclear from your question and code comments exactly where the NullReferenceException is being thrown from. Does the SelectSingleNode line throw an exception or return a null that leads to a NullReferenceException in the next line? — adv12
– adv12, Commented Jan 13, 2016 at 17:46
County is not a node. It's a simple element. You could even serialize the XML into an object. I personally prefer this way. So if your XML has always the same structure, You could make a class of that Type and create an object with serialization. — etalon11
– etalon11, Commented Jan 13, 2016 at 18:06

Rafael Ribeiro · Accepted Answer · 2016-01-13 18:20:49Z

1

What about to user XDocument() from System.Xml.Linq? Assuming that this xml file isn't a tree...

XDocument xmlDoc = new XDocument();
var sr = new System.IO.StreamReader(response.GetResponseStream())
xmlDoc = XDocument.Parse(sr.ReadToEnd());

var strCountry = xmlDoc.Root.Element("Country");

if the xml have children, use xmlDoc.Root.Descendants()

answered Jan 13, 2016 at 18:20

Rafael Ribeiro

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Comments

Community · Accepted Answer · 2017-05-23 11:59:12Z

0

If I had more reputation I would have added a comment pointing you to this this StackOverflow article but I can't create comments yet so it has to be an answer.

This is probably a duplicate so if someone can flag it, please do.

This has to do with the namespaces, specifically the xmlns="http://ws.cdyne.com/" part.

Create a XmlNamespaceManager and add the namespace.

XmlDocument xmlDoc = new XmlDocument();
XmlNamespaceManager namespaces = new XmlNamespaceManager(xmlDoc.NameTable);
namespaces.AddNamespace("ns", "http://ws.cdyne.com/");
xmlDoc.Load(response.GetResponseStream());
XmlNode msgnode = xmlDoc.DocumentElement.SelectSingleNode("/ns:IPInformation/ns:Country",namespaces);
string msgname = msgnode.InnerText;

edited May 23, 2017 at 11:59

CommunityBot

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answered Jan 13, 2016 at 19:45

Exxoff

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