
Introduction
ASP.NET UpdatePanel control allows to build rich, client-centric Web applications.
UpdatePanel controls refresh only selected part of the page instead of refreshing the whole page with a post back. In another words this is performing a partial-page update. A Web page that contains a
ScriptManager control and one or more UpdatePanel controls can automatically participate in partial-page updates, without custom client script.
When using JavaScript or jQuery in UpdatePanel enabled web page, everything will work fine at the first page load, but after any asynchronous post back happens by UpdatePanel, all JavaScript and jQuery effects will vanish.
Why is this happening?
Because, When the UpdatePanel post back triggers, the existing markup will overwrite with the markup generated by
UpdatePanel on the post back, which destroys all event handlers from HTML elements in the
UpdatePanel.
What is the solutions?
There are a couple of ways to fix this. In this article, IMO the easiest solution for this problem is to use Sys.Application inside UpdatePanel to call JavaScript, jQuery functions after each Asynchronous post back event.
Example:
In example below, I used an asp button for post back event and jQuery to show a message when Click Me! link is clicked.
JavaScript/jQuery function:
<script type="text/javascript">
function jScript() {
$("#click").click(function () {
alert("Clicked Me!");
});
}
</script>
ASP.NET UpdatePanel with JavaScript/jQuery re-call function:
<%-- Script Manager for ASP.NET AJAx --%>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<%-- // Script Manager End --%>
<%--ASP.NET UpdatePanel control to refresh page withtout post back--%>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<%-- Contetn template to put all ASP.NET controls for AJAX --%>
<ContentTemplate>
<%-- Re-Calling JavaScirpt/jQuery function on each Asynchronous post back. --%>
<script type="text/javascript" language="javascript">
Sys.Application.add_load(jScript);
</script>
<%-- // Re-Calling function End --%>
<%-- ASP.NET button for post back --%>
<asp:Button ID="btnPostBack" runat="server"
OnClick="btnPostBack_Click" Text="Click To Postback" />
<%-- // ASP.NET button End --%>
<%-- Link for showing the message on its click event --%>
<a href"#" id="click">Click Me!</a>
<%-- // Link End --%>
</ContentTemplate>
<%-- // Contetn template End --%>
</asp:UpdatePanel>
<%-- // ASP.NET UpdatePanel End --%>
ASP.NET (C#) code for button:
protected void btnPostBack_Click(object sender, EventArgs e)
{
btnPostBack.Text = "UpdatePanel PostBack Happened";
}
Conclusion
After calling JavaScript/jQuery functions inside UpdatePanel using
Sys.Applicaiton.add_load() event handler, you will be able to solve the problem.
Feel free to comment, suggest or give your feedback.
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Working in UpdatePanels – ASP.NET appeared first on Noor Ahmad Feroozi's Blog.