InfoPath Dev

 Hi all,

 I'm currently trying to set a field to 1 when another field is changed. All the tests in VSTA works but when I run infopath it crashes. Any help on this would be amazing! 

Here's the code: 

 Public Sub Incoming_Agent_Login_Changed(ByVal sender As Object, ByVal e As XmlEventArgs)
            Dim node As IHTMLDOMNode
            node = MainDataSource.CreateNavigator().SelectSingleNode("/my:myFields/my:Retrieve_Info", NamespaceManager)
            node.text = "1"
        End Sub

 And the error:

  System.InvalidCastException
Unable to cast object of type 'Microsoft.Office.InfoPath.MsxmlNavigator' to type 'mshtml.IHTMLDOMNode'.
   at NSTAT_v5pt5_0.FormCode.Incoming_Agent_Login_Changed(Object sender, XmlEventArgs e) in C:\Users\wilcojos\AppData\Local\Temp\vsta\1e5cd4420e40498dbbc128d44b5946e0\FormCode.vb:line 46
   at Microsoft.Office.InfoPath.Internal.XmlEventHost.GenericProxy(Object genericDelegate, DataDOMEvent dataDOMEvent, InfoPathEvents type)
   at Microsoft.Office.InfoPath.Internal.XmlEventHost.ChangedProxy(DataDOMEvent dataDOMEvent)
   at Microsoft.Office.Interop.InfoPath.SemiTrust._DataDOMEventSink_SinkHelper.OnAfterChange(DataDOMEvent pDataDOMEvent)

Been searching and searching but cannot find an answer. Thank you in advance. :)

 Your node variable should be an XPathNavigator in InfoPath - here's an MSDN link. https://msdn.microsoft.com/en-us/library/bb509311(v=office.12).aspx - it says it is for IP 2007, but 2010 and 2013 use very similar concepts.