DropDownList pass paramater

[jellybeannn]

I want to create a dropdownlist when an item is selected the user is redirected to another page and content about the item is displayed, all of this is done with stored procedures, but it does not seem to pass parameters to the stored procedure.
Can anyone help please?

This does not seem to work:

<HeaderTemplate>
        Select Width:
</HeaderTemplate>
<ItemTemplate>
            <asp:DropDownList ID="DropDownList1" 
                runat="server" AutoPostBack="True" 
                DataSourceID="SqlDataSource1"
                DataTextField="Width" 
                DataValueField="WidthID" 
                SelectedValue='<%# Eval("WidthID") %>'
                NavigateUrl='<%# Link.ToWidth(Eval("WidthID").ToString())%>'
                Width="100px" AppendDataBoundItems="true" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
             </asp:DropDownList>
    <asp:HyperLink ID="HyperLink1" runat="server"
        text="Click">
    </asp:HyperLink>
</ItemTemplate>
</asp:FormView>