How to get value through data grid view selected index changed ?

Protected Sub dg1_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles dg1.SelectedIndexChanged

im connectionString As String = "Data Source = ***; User ID = ***; Password = ***;"
        Dim sqlConnection As OracleClient.OracleConnection = New OracleClient.OracleConnection(connectionString)

        Dim queryString As String = "select * from abc where device = '"(dg1.Rows(1).Cells("I_NSPN95").ToString) '""

        Dim sqlCommand As OracleClient.OracleCommand = New OracleClient.OracleCommand(queryString, sqlConnection)
        sqlCommand.CommandTimeout = 0

        sqlCommand.Parameters.AddWithValue(":strDevice", OracleType.Char).Value = (dg1.Rows(1).Cells("I_NSPN95"))

        Dim dataAdapter As OracleClient.OracleDataAdapter = New OracleClient.OracleDataAdapter(sqlCommand)
        Dim dataSet As DataSet = New DataSet
        dataAdapter.Fill(dataSet)

    End Sub
End Class