Comparing database values with values from a gridview

cn.Open()
      For j As Integer = 0 To DataGridView1.Rows.Count - 1
          Dim cmd As New SqlCommand("select Codearticle from DetailReceptionFrs where Codearticle='" & DataGridView1.Rows(j).Cells("Article").Value & "' ", cn)
          Using da As SqlDataReader = cmd.ExecuteReader

              While da.Read
                  If da.HasRows Then
                      Form2.Show()
                  Else
                      MsgBox("nnnnnnnnnn")
                  End If
              End While
              da.Close()
          End Using

      Next