Updatepanel gives full postback instead of asyncpostback

I have run into what seems to be a very famous problem: My updatepanel fires a full postback instead of a async postback. The normal solution is to give all controls you add dynamically an ID, which I have done, but I still get a full postback instead of my async postback…

Here’s the code:

HTML:

<asp:UpdatePanel ID="ItemsUpdatePanel" runat="server" UpdateMode="Conditional" ChildrenAsTriggers="False">
   <Triggers>
   </Triggers>    
   <ContentTemplate>
   <asp:ListView ID="PlayerItems" runat="server" GroupItemCount="5" 
                                    onitemdatabound="PlayerItems_ItemDataBound">
   <LayoutTemplate>

   ... Listview stuff ...

    </asp:ListView> 

    </ContentTemplate>
</asp:UpdatePanel>

The interesting part is the C# code behind (method PlayerItems_ItemDataBound), which is like the following:

            ImageButton imgBtn = new ImageButton();
            imgBtn.ID = "itemBtn";
            imgBtn.Width = Unit.Pixel(30);
            imgBtn.ImageUrl = "~/Images/Game/Items/" + myItem.ItemImageUrl;

            ContextMenu menu = new ContextMenu();
            menu.BoundControls.Add(imgBtn);
            menu.ItemCommand += new CommandEventHandler(menu_ItemCommand);

            menu.AutoHide = true;
            menu.RolloverColor = Color.Gray;
            menu.ID = "MenuMenu";

            Panel panel = (Panel)(e.Item.FindControl("ItemPanel"));
            panel.Controls.Add(imgBtn);
            panel.Controls.Add(menu);

            AsyncPostBackTrigger trig = new AsyncPostBackTrigger();
            trig.ControlID = menu.UniqueID;
            trig.EventName = "ItemCommand";
            ItemsUpdatePanel.Triggers.Add(trig);

So, I actually add an AsyncPostBackTrigger to the menu, so the ItemCommand event should be registered. What happends when I click an item in this contextmenu, is a full postback happends.

I have been trying to play with the ChildrenAsTriggers property without help. I have also been moving the AsyncPostBackTrigger code up and down, also without help.

Thanks a lot beforehand..!
Lars

Answers:

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Method 1

I had the same experience when populating a CheckBoxList inside a ListView inside a Panel in an UpdatePanel. It was solved by adding this code in the CheckBoxList:

ClientIDMode="AutoID"

Method 2

From the AsyncPostBackTrigger documentation:

Programmatically adding
AsyncPostBackTrigger controls is not
supported. To programmatically
register a postback control, use the
RegisterAsyncPostBackControl method of
the ScriptManager control. Then call
the Update method of the UpdatePanel
control when the control posts back.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0