XmlNode.InnerText breaks if data is null

Question

I have a script task in VS 2008. In this script task I get a Data Set and convert it into XML, and loop through the nodes:

Dim dsHistory As New DataSet
dsHistory = GetHistoryByYear(Year)


Dim HistoryDoc As New XmlDocument
HistoryDoc.LoadXml(dsHistory.GetXml)


Dim HistoryStudentList As XmlNodeList
Dim StudentNode as XmlNode
HistoryStudentList = HistoryDox.SelectNodes("/NewDataSet/Table")
dsHistory = Nothing


For Each HistoryStudentNode In HistoryStudentList

    Dim dsCurrentAssessment As New DataSet
    dsCurrentAssessment = GetCurrentAssessmentData(...)

    ...code to make sure dataset has data...

    Dim CurrentAssessmentDoc As New XmlDocument
    CurrentAssessmentDoc.LoadXml(dsCurrentAssessment.GetXml)
    Dim CurrentAssessmentNode As XmlNode
    CurrentAssessmentNode = CurrentAssessmentDoc.SelectSingleNode("/NewDataSet")


    For Each CurrentAssessment As XmlNode In CurrentAssessmentNode.SelectNodes("Table")

        InsertAssessmentHistory(HistInstanceID, CurrentAssessment.Item("TITLE").InnerText, CurrentAssessment.Item("CONTENT").InnerText, CurrentAssessment.Item("TYPE").InnerText, CDate(convertAssessmentDate(CurrentAssessment.Item("ADMINISTRATION_DATE").InnerText)), CurrentAssessment.Item("REPORTING_METHOD").InnerText, CurrentAssessment.Item("SCORE_RESULTS").InnerText, CurrentAssessment.Item("INTERPRETATION").InnerText, CStr(htHistory("ASSESSMENT_ACTION")))

    Next
Next

The issue I am having is with the InsertAssessmentHistory method, specifically calling CurrentAssessment.Item("SCORE_RESULTS").InnerText. The data set is returning null data for one of the records, and it looks like when .InnerText is called on that record it fails with "Object Reference not set to an instance of an object" because the XML tag "...".

Is there a way to call .InnerText, and if there's no data then return null?

Answer 1

With @codexer's guidance I was able to get it to work. The inner loop now looks like this:

For Each CurrentAssessment As XmlNode In CurrentAssessmentNode.SelectNodes("Table")

    Dim ScoreResults As String
    Dim Interpretation As String


    If CurrentAssessment.Item("SCORE_RESULTS") Is Nothing Then
        ScoreResults = Nothing
    Else
        If CurrentAssessment.Item("SCORE_RESULTS").InnerText Is Nothing Then
            ScoreResults = Nothing
        Else
            ScoreResults = CurrentAssessment.Item("SCORE_RESULTS").InnerText
        End If
    End If


    If CurrentAssessment.Item("INTERPRETATION") Is Nothing Then
        Interpretation = Nothing
    Else
        If CurrentAssessment.Item("INTERPRETATION").InnerText Is Nothing Then
            Interpretation = Nothing
        Else
            Interpretation = CurrentAssessment.Item("INTERPRETATION").InnerText
        End If
    End If



    InsertAssessmentHistory(HistInstanceID, _
        CurrentAssessment.Item("TITLE").InnerText, _
        CurrentAssessment.Item("CONTENT").InnerText, _
        CurrentAssessment.Item("TYPE").InnerText, _
        CDate(convertAssessmentDate(CurrentAssessment.Item("ADMINISTRATION_DATE").InnerText)), _
        CurrentAssessment.Item("REPORTING_METHOD").InnerText, _
        ScoreResults, _
        Interpretation, _
        CStr(htHistory("ASSESSMENT_ACTION")))
Next