Visual Basic.NET - problema con método para hacer Select

HasRows

Public Function CONEXAO_BANCO_DADOS_SQL() As SqlConnection

        Dim conexao As String = "aqui colocas la conexio de tu base de datos"

        Return New SqlConnection(conexao)

    End Function

private sub  salvar_registro

Using cn As SqlConnection = CLASE_CONEXION.MI_CONEXION

            Try

                cn.Open()

                Dim validar_codigo As String = "SELECT COUNT(*) FROM TABLA_1 INNER JOIN TABLA_2 ON  TABLA_1.COD_1 = TABLA_2.COD_1  WHERE TABLA_1.COD1 = '" &TXTCODIGO.TEXT &"'"

                Dim cmd As New SqlCommand(validar_codigo , cn)

             DIM i as interger

i=cint(cmd.ExecuteScalar())

if i=0 then

dim sql as string = "INSERT INTO TABLA_1 (COD_1, NOMBRE, APELLIDO) VALUES (@COD_1, @NOMBRE, @APELLIDO) "

      Dim cmd_2 As New SqlCommand(sql , cn)

   cmd_2.Parameters.Add(New SqlParameter("@COD_1", SqlDbType.VarChar)).Value = txtcajatexto_1.text

                cmd_2.Parameters.Add(New SqlParameter("@NOMBRE", SqlDbType.VarChar)).Value = txtcajatexto_2.text

 cmd_2.Parameters.Add(New SqlParameter("@APELLIDO", SqlDbType.VarChar)).Value = txtcajatexto_3.text

                cmd_2.ExecuteNonQuery()

                MsgBox("REGISTRO SALVO CON SUCESO. ! ", MsgBoxStyle.Information, " SUCESO")

ELSE

    MsgBox("REGISTRO YA EXISTE, VERIFICAR. ! ", MsgBoxStyle.Information, " ERROR")

end if

            Catch ex As Exception

              MSG(EX.MESSAGE)

            Finally

                cn.Close()

            End Try

        End Using

    End Sub