NullReferenceException - Getting the string contained in each item

[mcmahon]

Hi,
I keep getting the error " Object reference not set to an instance of an object." in relation to the line : selA = CType(lstStudents.Items(r.Index), String)

Any advice/help?

            Dim BRow As DataRow
            Dim i As Integer
            Dim selA As String
            selA = CType(lstStudents.Items(r.Index), String)
            BRow = objDataSet.Tables("tblStudent").Rows.Find(selA)
            Do While selA <> ""
                If BRow IsNot Nothing Then
                    Dim studentRows() As DataRow = BRow.Item("StudentID")
                    If studentRows.Length > 0 Then
                        For Each student As DataRow In studentRows
                            Dim strID As Integer = student("StudentID")
                            'add this item
                            objCurrentRow1.Item("StudentID") = strID
                        Next
                    End If
                End If
                i = i + 1
            Loop 

'r' has been declared earlier as

Dim r As MeasureItemEventArgs

[Plater]

Are you sure it returns a string type for every index?
You have possibly a problem in a few places.
Looking at: selA = CType(lstStudents.Items(r.Index), String)
Is "r" always a value, or is it Nothing(null)?
Is "r.Index" always a valid number in the range of lstStudents, or does it sometimes = -1?
Does lstStudents.Items(r.Index) always produce a string type? Have you checked .GetType() to make sure its a string?