Link-DropDownList-with-SqlDataSource-and-do-the-editing

                                  runat="server"
                          AutoPostBack="True"
                          Width="280px"
                          DataSourceID="sourceProducts"
                          DataTextField="ProductName"
                          DataValueField="ProductID">

                                                         runat="server"
                                     DataSourceID="sourceProductDetails"
                                     Height="50px"
                                     Width="200px"
                                     AutoGenerateEditButton="True">

                                   runat="server"
                           ProviderName="System.Data.SqlClient"
                           ConnectionString="<%$ ConnectionStrings:Northwind %>"
                           SelectCommand="SELECT ProductName, ProductID FROM Products"/>
                                   runat="server"
                           ProviderName="System.Data.SqlClient"
                           ConnectionString="<%$ ConnectionStrings:Northwind %>"
                           SelectCommand="SELECT ProductID, ProductName, UnitPrice, UnitsInStock, UnitsOnOrder, ReorderLevel, Discontinued FROM Products WHERE ProductID=@ProductID"
                           UpdateCommand="UPDATE Products SET ProductName=@ProductName, UnitPrice=CONVERT(money, @UnitPrice), UnitsInStock=@UnitsInStock, UnitsOnOrder=@UnitsOnOrder, ReorderLevel=@ReorderLevel, Discontinued=@Discontinued WHERE ProductID=@ProductID">

Data Binding ASP.Net Tutorial