grid view problem

M trying to bind a datasource to the gridview in c# through services. No error or exception is generated, though gridview is not visible while executing the code.

WindowsFormsApplication2.salespost1_Service service = new WindowsFormsApplication2.salespost1_Service();

salespost1 sale=new salespost1();
sale=service.Read("No");
GridView1.DataSource = sale.SalesLines;
GridView1.DataBind();

//salepost1_service is of page 43