<%@ Page Language="C#" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server"> <title>Show Control Parameter</title> </head> <body> <form id="form1" runat="server"> <div> <asp:DropDownList id="ddlProducts" DataSourceID="srcProducts" DataTextField="Title" DataValueField="Id" Runat="server" /> <asp:Button id="btnSelect" Text="Select" Runat="server" /> <hr /> <asp:DetailsView id="dtlProduct" DataSourceID="srcProductDetails" Runat="server" /> <asp:SqlDataSource id="srcProducts" SelectCommand="SELECT Id,Title FROM Products" ConnectionString="<%$ ConnectionStrings:Products %>" Runat="server" /> <asp:SqlDataSource id="srcProductDetails" SelectCommand="SELECT * FROM Products WHERE Id=@Id" ConnectionString="<%$ ConnectionStrings:Products %>" Runat="server"> <SelectParameters> <asp:ControlParameter Name="Id" ControlID="ddlProducts" PropertyName="SelectedValue" /> </SelectParameters> </asp:SqlDataSource> </div> </form> </body> </html> File: Web.config <configuration> <connectionStrings> <add name="Products" connectionString="Data Source=.\SQLEXPRESS; AttachDbFilename=|DataDirectory|MyDatabase.mdf;Integrated Security=True;User Instance=True" /> </connectionStrings> </configuration>