Trigger an update of the UpdatePanel by a control that is in different ContentPlaceHolder

I have a page with two ContentPlaceHolders. One has a DropDown and another UpdatePanel with content.

How can I trigger update to the UpdatePanel by the DropDown’s selectedItemChanged event when they are in different ContentPlaceholders?

The following would not work since UpdatePanel1 doesn’t know about DropDown1:

<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional"  ChildrenAsTriggers="true">
    <ContentTemplate>
        Some content that needs to be updated here...
    </ContentTemplate>
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="DropDown1" EventName="SelectedIndexChanged" />
    </Triggers>
</asp:UpdatePanel>

One way is to make an ajax page method that would be called by javascript on the page when DropDown’s item is selected. Then in code behind, inside that page method, call UpdatePanel1.Update().

Is there an easier alternative?

Contents hide

Answers:

Method 1

Method 2

Method 3

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

From http://msdn.microsoft.com/en-us/library/system.web.ui.asyncpostbacktrigger.aspx

The control that the
AsyncPostBackTrigger references must
be in the same naming container as
the update panel for which it is a
trigger. Triggers that are based on
controls in other naming containers
are not supported.

The workaround is to use the UniqueID of the control that the
trigger is referencing. Unfortunately the UniqueID isn’t qualified
until the control has been added to its parent (and its parent
has been added to its parent, all the way up the control tree).

In your code behind, try:

UpdatePanel1.Triggers.Add(new AsyncPostBackTrigger()
{
    ControlID = DropDown1.UniqueID,
    EventName = "SelectedIndexChanged", // this may be optional
});

Method 2

In the code-behind file, you should be able to do:

ScriptManager.RegisterAsyncPostBackControl(dropdown1);

Method 3

You can enforce update any of page UpdatePanels by call updatePanel1.Update() method on server side.
For example during update updatePanel1 on button1.Click call updatePanel2.Update() and both panels will be updated.

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

0 0 votes

Article Rating