Disable page refresh after button click ASP.NET

Question

I have an asp button that looks like this:

Default.aspx

<asp:button id="button1" runat="server" Text="clickme" onclick="function" />

Default.aspx.cs

protected void function(object sender EventArgs e)
{
    // Do some calculation
}

However, whenever I press the button, the entire page gets refreshed. I have looked on this site and found many solutions, but none of them really works for my project. Here are some of the suggested solutions:

1. set onclick="return false;" // but then how do I run the function in the code-behind?
2. use !IsPostBack in Page_Load // but the page still refreshes completely. I don't want Page_Load to be called at all.
3. Disable AutoEventWireup. // making this true or false doesn't make a difference.

Does anyone have a solution to this, or is it really impossible?

Pharmacopoeia

use a callback, or ajax, or an update panel – Herne

Really depends on what you want to do. Look at AJAX as a solution. Also, you could use an update panel which does utilize AJAX. – Hawker

Thanks for great answers. I used an update panel and it worked perfectly! For other beginners out there like me, this video by Dan Wahlin really helped: youtube.com/watch?v=0hnW8sPJpPQ. – Pharmacopoeia

Answer 1

I would place the control inside of an Update panel. To do so, you would also need a script manager above it, so something like this:

 <asp:ScriptManager runat="server" ID="sm">
 </asp:ScriptManager>
 <asp:updatepanel runat="server">
 <ContentTemplate>
 <asp:button id="button1" runat="server" Text="clickme" onclick="function" />
 </ContentTemplate>
 </asp:updatepanel>

if a control inside the update panel does a postback, it will only reload the part of the page inside of the upate panel.Here is a link you may find useful from the MSDN site.

Herne

Do we have to write anything on the ScriptManager or it can be blank like above ? – Maurizio

Answer 2

I think there is a fundamental misunderstanding here of how ASP.Net works.

When a user first requests your page, an instance of your Page class is created. The ASP.Net framework runs through the page lifecycle with this page instance in order to generate html. The html response is then sent to the user's browser. When the browser receives the response it renders the page for the user. Here's the key: by the time rendering is complete, your page class instance was probably already collected by the .Net garbage collector. It's gone, never to be seen again.

From here on out, everything your page does that needs to run on the server, including your method, is the result of an entirely new http request from the browser. The user clicks the button, a new http request is posted to the web server, the entire page lifecycle runs again, from beginning to end, with a brand new instance of the page class, and an entirely new response is sent to the browser to be re-rendered from scratch. That's how ASP.Net (and pretty much any other web-based technology) works at its core.

Fortunately, there are some things you can do to get around this. One option is to put most of your current Page_Load code into an if (!IsPostBack) { } block. Another option is to set up your method with the [WebMethod] attribute and make an ajax request to the method from the button. Other options include calling web services from custom javascript and ASP.Net UpdatePanel controls.

What works best will depend on what other things are on the page that user might have changed.

Gamester

Answer 3

That is normal behavior for asp.net, you are actually causing a postback of the the page in order for the associated event to be called on the server.

I would suggest working with update panels but if you just need something to happen on the backend without it causing any major change on the web page, I would use jquery and a web service. The main reason for me is that update panels create huge viewstate objects.

Have a look here for asp.net ajax : http://www.asp.net/ajax

And here for an example of jquery and wcf : http://www.codeproject.com/Articles/132809/Calling-WCF-Services-using-jQuery

Tryst

Answer 4

I have a similar problem. this answer helps me a lot. in your asp button.<asp:button id="button1" runat="server" Text="clickme" OnClientClick="return SomeMethod();" /> and in the SomeMethod which is a js method do your logic like manipulating your page then return false as the mentioned answer suggest.

Inexpungible