Question

I have a page in which one chooses from a selection of dynamically generated buttons. The ASPX code is as follows:

<div>
<asp:Repeater ID="rptrHalls" runat="server" OnItemCommand="Choose_Hall">
    <ItemTemplate>
        <asp:Button ID="btnChooseHall" runat="server"
        CommandName="<%# Container.DataItem %>" Text="<%# Container.DataItem %>"
         />
    </ItemTemplate>
</asp:Repeater>
</div>

When the page is loaded the following code is used to generate the buttons:

        ' Show which halls they are eligible for.
    Dim dbHalls As New pbu_housingDataContext
    'Dim gender As String = Session("gender").ToString
    Dim selectedHalls = (From sh In dbHalls.Rooms _
                         Where sh.gender = Session("gender").ToString _
                         Where sh.current_occupancy < sh.max_occupancy _
                         Where sh.is_available = True _
                         Select sh.building_name).Distinct()
    rptrHalls.DataSource = selectedHalls
    rptrHalls.DataBind()

When the user clicks on a dynamically generated button the following code is triggered:

    Public Sub Choose_Hall(ByVal Sender As Object, ByVal e As RepeaterCommandEventArgs)
    Session("Hall") = e.CommandName.ToString
    Response.Redirect("select_room.aspx")
    End Sub

When I first tried running the code I received an error message of “Invalid postback/callback argument”. I set the ASPX page to have a enableEventValidation=”false” property and tried running it again. It generates the page fine but when I click on a dynamically generated button it acts as if it is loading something and then just brings me back to select_hall.aspx (the page all this code is one), when (as you can see above) it should take me to select_room.aspx.

Answer 1

So, it appears I figured out the issue. In the Page_Load section of select_hall.aspx I had a call to the database. Every time I called the page it was reloading these values – and I think they were not matching up to the previously cached properties in some way (e.g. underlying ASP.NET auto-naming), this was causing the issue. I added a If Not Page.IsPostBack Then clause inside which I placed the data binding code and now it appears to work correctly.