Object reference not set to an instance of an object

I have the following code where I am extracting data from a set of controls for an xml class. I iterate through my controls and pull my control id and selected value for radiobuttonlist or checkboxlist. I am successfully iterating through my controls and can display the result set (surveylabel1). When I add the code to add detail items to my responsedataset i get an error "Object reference not set to an instance of an object."

I am using the integer i in my iteration and to define the detail, is the variable i not available inside of my Case statement, or do I have another problem with my code?

Thank you.

 Private Function ExtractResults() As SResponse.Schema7Ihsurveyresponse
 Dim currentUser As New AccBusiness.User( _
 CType(Context.User, SitePrincipal))
 Dim sb As StringBuilder = New StringBuilder
 sb.Append("Answers: ")
 Dim msgtext As String
 Dim ctrl, ctl2 As Control
 Dim rb As RadioButtonList
 Dim lb As TextBox
 Dim ck As CheckBoxList
 Dim i As Integer
 Dim id As Integer
 Dim item As ListItem
 Dim newResponse As New SResponse.Schema7Ihsurveyresponse
 newResponse.surveyid = 1
 newResponse.Userid = currentUser.UserId
 For i = 0 To (Controls().Count - 1)
 Dim newresponsedetail(i) As SResponse.Schema7IhsurveyresponseIhsresponsedetail
 ctrl = Controls(i)
 id = -1
 Select Case ctrl.GetType.Name
 Case "RadioButtonList"
 rb = CType(ctrl, RadioButtonList)
 sb.Append(rb.ID & ": " & rb.SelectedValue)
 newresponsedetail(i).question = rb.ID.ToString
 newresponsedetail(i).result = CInt(rb.SelectedValue)
 Case "CheckBoxList"
 ck = CType(ctrl, CheckBoxList)
 For Each item In ck.Items
 If item.Selected Then
 sb.Append(ck.ID & ": ")
 sb.Append(item.Value & ", ")
 'newresponsedetail(i).question = ck.ID.ToString
 'newresponsedetail(i).result = CInt(item.Value)
 End If
 Next
 End Select
 sb.Append(" - ")
 Next
 Surveylabel1.Text = sb.ToString
 End Function

Hi,
i couldn't find "responsedataset" in ur code ?
I am sorry I should have been clearer in my question. I am trying to iterate through my controls adding the Control.id and control.selectedvalue to the detail of my sresponse.schema7idsurveyresponse (please forgive the long names - I plan to clean this up later).

I have alltered my code for ExtractResults() from my previous post and add the code for my sresponse class.

I commented out my execute scalar and set my return for my Addresponse (newresponse) function to be the XMLResoponse string for troubleshooting. Although I am not getting any errors, I am also not getting any XMLResponse string. Why would that be? What am I missing?

 Private Function ExtractResults() As SResponse.Schema7Ihsurveyresponse
 Dim currentUser As New AccBusiness.User( _
 CType(Context.User, SitePrincipal))
 Dim sb As StringBuilder = New StringBuilder
 sb.Append("Answers: ")
 Dim msgtext As String
 Dim ctrl, ctl2 As Control
 Dim rb As RadioButtonList
 Dim lb As TextBox
 Dim ck As CheckBoxList
 Dim i As Integer
 Dim id As Integer = (Controls().Count - 1)
 Dim item As ListItem
 Dim newResponse As New SResponse.Schema7Ihsurveyresponse
 newResponse.surveyid = 1
 'newResponse.Userid = currentUser.UserId
 newResponse.Userid = 1
 Dim details(id) As SResponse.Schema7IhsurveyresponseIhsresponsedetail
 For i = 0 To (Controls().Count - 1)
 details(i) = New SResponse.Schema7IhsurveyresponseIhsresponsedetail
 ctrl = Controls(i)
 id = -1
 Select Case ctrl.GetType.Name
 Case "RadioButtonList"
 rb = CType(ctrl, RadioButtonList)
 sb.Append(rb.ID & ": " & rb.SelectedValue)
 details(i).question = rb.ID.ToString
 'details(i).result = CInt(rb.SelectedValue)
 details(i).result = 1
 Case "CheckBoxList"
 ck = CType(ctrl, CheckBoxList)
 For Each item In ck.Items
 If item.Selected Then
 sb.Append(ck.ID & ": ")
 sb.Append(item.Value & ", ")
 details(i).question = ck.ID.ToString
 'details(i).result = CInt(item.Value)
 details(i).result = 2
 End If
 Next
 End Select
 sb.Append(" - ")
 Next
 newResponse.ihsresponsedetail = details
 Dim responseID As String = SResponse.addresponse(newResponse)
 Surveylabel1.Text = "Response: " & responseID & sb.ToString
 End Function
 Private Sub btnSurveySubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSurveySubmit.Click
 ExtractResults()
 End Sub
 End Class

my sresponse class:

 <System.Xml.Serialization.XmlRootAttribute([Namespace]:="", IsNullable:=False)> _
 Public Class Schema7
 '<remarks/>
 <System.Xml.Serialization.XmlElementAttribute("ihsurveyresponse", Form:=System.Xml.Schema.XmlSchemaForm.Unqualified)> _
 Public Items() As Schema7Ihsurveyresponse
 End Class
 '<remarks/>
 Public Class Schema7Ihsurveyresponse
 '<remarks/>
 <System.Xml.Serialization.XmlElementAttribute("ihsresponsedetail", Form:=System.Xml.Schema.XmlSchemaForm.Unqualified)> _
 Public ihsresponsedetail() As Schema7IhsurveyresponseIhsresponsedetail
 '<remarks/>
 <System.Xml.Serialization.XmlAttributeAttribute()> _
 Public surveyid As Integer
 '<remarks/>
 <System.Xml.Serialization.XmlIgnoreAttribute()> _
 Public surveyidSpecified As Boolean
 '<remarks/>
 <System.Xml.Serialization.XmlAttributeAttribute()> _
 Public Userid As Integer
 '<remarks/>
 <System.Xml.Serialization.XmlIgnoreAttribute()> _
 Public UseridSpecified As Boolean
 End Class
 '<remarks/>
 Public Class Schema7IhsurveyresponseIhsresponsedetail
 '<remarks/>
 <System.Xml.Serialization.XmlAttributeAttribute()> _
 Public id As Integer
 '<remarks/>
 <System.Xml.Serialization.XmlIgnoreAttribute()> _
 Public idSpecified As Boolean
 '<remarks/>
 <System.Xml.Serialization.XmlAttributeAttribute()> _
 Public question As String
 '<remarks/>
 <System.Xml.Serialization.XmlAttributeAttribute()> _
 Public response As Integer
 '<remarks/>
 <System.Xml.Serialization.XmlIgnoreAttribute()> _
 Public responseSpecified As Boolean
 '<remarks/>
 <System.Xml.Serialization.XmlAttributeAttribute()> _
 Public result As Integer
 '<remarks/>
 <System.Xml.Serialization.XmlIgnoreAttribute()> _
 Public resultSpecified As Boolean
 End Class
 Public Shared Function addresponse(ByVal newResponse As Schema7Ihsurveyresponse) As String
 Dim serializer As XmlSerializer
 serializer = New XmlSerializer(GetType(Schema7Ihsurveyresponse))
 Dim ms As MemoryStream
 'Try
 ms = New MemoryStream
 serializer.Serialize(ms, newResponse)
 'Catch ex As Exception
 ' ms.Close()
 'Return (-1)
 ' End Try
 ms.Close()
 Dim xmlresponse As String = System.Text.Encoding.UTF7.GetString(ms.ToArray)
 Dim cmd As New SqlClient.SqlCommand
 cmd.CommandText = "insertResponseDetails"
 cmd.CommandType = CommandType.StoredProcedure
 cmd.Parameters.Add(New SqlClient.SqlParameter("@.xml", xmlresponse))
 Dim cn As New SqlClient.SqlConnection
 cn.ConnectionString = Configuration.ModuleConfig.GetSettings.ConnectionString
 cmd.Connection = cn
 cn.Open()
 Dim newResponseid As Integer
 'Try
 'newResponseid = CInt(cmd.ExecuteScalar)
 ' Catch ex As Exception
 'Return -1
 'End Try
 Return xmlresponse
 End Function
 End Class