Question

Lets say I have a drop down list and a grid view on a page like this

<asp:GridView ID="gvCategories" runat="server" >
<Columns>
<asp:HyperLinkField DataTextField="CategoryName"            DataNavigateUrlFields="CategoryID"     DataNavigateUrlFormatString="~/Learning.aspx?categoryID={0" />
</Columns>
</asp:GridView>

I’d like to add this to the URL:
&view=<%=SelectedDropdownlistvalue%>

How can I do this?

Answer 1

I would use TemplateField as:

<asp:GridView ID="gvCategories" runat="server" >
<Columns>
   <asp:TemplateField>
      <ItemTemplate>
        <asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl='<%# Eval("CategoryName", "~/Learning.aspx?categoryID={0}")+" &view=" + DropDownList1.SelectedValue %>' 
                        Text="Goto Page"></asp:HyperLink>
       </ItemTemplate>
   </asp:TemplateField>
 </Columns>
</asp:GridView>

Remember the DropDownList.SelectedValue is obtained at postBack, so the link is constructed at that time. To change the link dynamically when the value of the dropdownlist changes set the AutoPostBack=”true” of the dropdownlist.