DataTable case VB.Net

Dim tb As TextBox = CType(UserIdTextBox, TextBox)
           Dim userName As String = tb.Text
           Dim gvw As GridView = CType(sender, GridView)
           Dim scheduleId As Integer = Integer.Parse(gvw.SelectedRow.Cells(1).Text)

           Dim caspbll As New CASpBLL

           Dim schedDt As tbCASp_ExamScheduleDataTable = caspbll.GetExamSchedule(scheduleId)
           Dim appDt As QuickAppInfoDataTable = caspbll.AppInfoSummary(userName)
           Dim regDt As tbCASp_RegistrationDataTable = caspbll.GetExamReg(userName, scheduleId)
           If appDt IsNot Nothing AndAlso appDt.Rows.Count = 1 Then
               If regDt IsNot Nothing AndAlso regDt.Rows.Count = 0 And (Not caspbll.AlreadyRegisteredForThisExam(appDt(0).ApplicationID, schedDt(0).ExamID)) Then
                   Dim RegNumber As String = ""
                   Dim RegId As Integer
                   RegId = caspbll.NewRegistration(appDt(0).ApplicationID, scheduleId, HttpContext.Current.Request.UserHostAddress, RegNumber)
                   Dim CASp As New CASpBLL
                   CASp.UpdateExamRegFromDSA601(Today.ToShortDateString(), SpecialAccomodationCheckBox.Checked, NoSaturdayExamCheckBox.Checked, RegId)
                   Response.Redirect(String.Format("view_registration.aspx?regid={0}", RegId.ToString()))
               Else
                   lblErrorMsg.Visible = True
                   lblErrorMsg.Text = "User has already registered for a session for this exam"
               End If
           Else
               lblErrorMsg.Visible = True
               lblErrorMsg.Text = "UserId doesn't exist."
           End If