Asp – How to populate UpdatePanel in Repeater in ASPX (not code-behind)

asp.netasp.net-ajax

I have a Repeater which displays a list of items (in a grid-like/table view). When a user clicks an item, I display an UpdatePanel under this item with additional information relevant to the item (similar to Accordion control). I know how to populate the elements of the UpdatePanel in code-behind (I pass the ID of the selected element in the Repeater control as CommandArgument, get additional info for this ID, and set up the text fields of the active UpdatePanel controls). But I'm wondering if I could set up binding directly in the ASPX (instead of code-behind). When I used the <%= %> syntax to assign text fields of the UpdatePanel control the values of the page properties, e.g. <%= Comment %>, it sort of worked, but it changed the fields of all UpdatePanels in the repeater. Is there any way to bind the active UpdatePanel to the current values and leave already bound UpdatePanels unchanged?

Best Answer

Are you looking to display a container that displays additional information? Is there other activity in the "box" that requires it be an updatepanel?

<asp:repeater>
   <itemtemplate>
      <%# Eval("Name") %> <%# Eval("LastName") %><br />
      <span onclick="$get('<%# Eval("Id") %>')">View Age</span>
      <div id="<%# Eval("Id")%>" style="display:none;">
          Age: <%# Eval("Age") %>
      </div>
   <itemtemplate>
</asp:repeater>

Ithink that's right, some syntax may be off a bit (typing without intellisense). Would that work? I used ID as a unique identifier for the div id and the onclick command. You could also use jquery, asp:controls or whatever else you wanted.

Related Solutions

UpdatePanel, Repeater, DataBinding Problem

Thanks for reminding me why I stopped using ASP.NET controls. This is the exact type of nightmare that has made too many projects go way over budget and schedule.

My advise to you is to think of the simplest way to implement this. You can try to bend over backwards in order to get this to work the ASP.NET way or take the shortest route. All you're doing is generating HTML, it should never be that difficult.

The most likely cause of your problem is that the ViewState is stored in the page which doesn't get updated on a partial postback. So with every change in the update panel you'll postback the initial viewstate of the page.

Try replacing the repeater with a simple for-loop (and ignore the people who start complaining you shouldn't mix markup and code). Replace your databinding statements with <%= %>. That eliminates the view state all together and should remove any removed row from re-appearing.

C# – How to access textbox, label inside update panel from code behind using asp.net web forms

The problem isn't with UpdatePanel, but with the Repeater. Controls inside the update panel can be directly accessed within the scope of the page (such as the repeater itself), whilst controls within the repeater have to be "found" during or after they have been bound. Your code within the repeater is a template for many items and not specific to any one.

I'd suggest adding an ItemDataBound event to your repeater and perform the logic inside this event as each item is being bound to the repeater.

<asp:Repeater ID="rptCommentList" runat="server" EnableViewState="false"
     OnItemDataBound="rptCommentList_ItemDataBound">

protected void rptCommentList_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) 
    {
        // get the data item
        MyObject myObject = (MyObject)e.Item.DataItem;

        // find the label
        Label lblComUserName = (Label)e.Item.FindControl("lblComUserName");

        // do the magic!
        if (myObject.comAnonymous)
             lblComUserName.Visible = false;
    }
}

Obviously, replace MyObject with the object type of the collection/list/table you are binding to the repeater in the first place.

Hope that helps.

Best Answer

Related Solutions

UpdatePanel, Repeater, DataBinding Problem

C# – How to access textbox, label inside update panel from code behind using asp.net web forms

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