How to add retrived object from oCmd.ExecuteScalar.ToString as a datarow element

   Public Sub saveData(ByVal strConn As String, ByVal strSQL As String)
       
        Dim oCmd As New SqlClient.SqlCommand
        Dim oAdapt As New SqlClient.SqlDataAdapter
        Dim oConn As New SqlClient.SqlConnection
        Try

            oConn.ConnectionString = strConn
            oConn.Open()

            oCmd = New SqlClient.SqlCommand(strSQL, oConn)

            Dim dr As DataRow
            dr = DTtrackingno.NewRow
            temp(0) = oCmd.ExecuteScalar.ToString

            '****I need to assign this temp object as data row below is the code I wrote but its giving me error
            dr.Item(0) = temp

            DTtrackingno.Rows.Add(dr)

            DTtrackingno.AcceptChanges()

        Catch ex As Exception
            Throw New Exception("Error in getData()- Datatable" & ex.Message)

        Finally
            If oConn.State = ConnectionState.Open Then
                oConn.Close()
                oConn.Dispose()
            End If

        End Try

    End Sub

Above is my code and I have marked *** at the place I am getting the error.
All I need to do is add the retrived object to a  datarow of data table DTtrackingno.

Thanks,