Comments on: Dynamically Loading ASP.NET User Controls with jQuery

By: Poul Bak

Poul Bak — Wed, 04 Nov 2009 08:44:35 +0000

Instead of messing with custom attributes, you could simply use the following:

Simply name your ‘runnable’ usercontrols like that (with ‘.ajax’ in name), works the same.

By: John H.

John H. — Fri, 09 Oct 2009 08:43:27 +0000

To run with localhost I made some changes…
Default.aspx:
$("#datetime").load("Controls/Datetime.ascx");
$("#datetime").load("DateTimeServerControl.sch");
AjaxServerControlHander:
string typeName = path.Substring(0, path.Length – 4);
typeName = typeName.Substring(typeName.LastIndexOf(‘/’) + 1);

It works great. Thanks Mikkel!

By: wheels for sale

wheels for sale — Tue, 29 Sep 2009 06:42:48 +0000

Great idea and I thank you for all that work, but your example is lacking how to implement it. Kind of like all the wheels and cogs are there, but the screws are missing. Please post a sample project?

By: Mikkel Ovesen

Mikkel Ovesen — Thu, 16 Jul 2009 23:39:20 +0000

@rac: I have updated the source code to support async. calling of a WebControl. When using this approach, it is not possible to use the ViewState for these controls, and this excludes using some standard ASP.NET controls. If you want make use of the ViewState, it would be easier to just use Microsoft ASP.NET Ajax partial rendering.

@Steve: You are correct, the first version was coded quickly and only as a sample. But I have updated the sourcecode.

By: Steve

Steve — Thu, 16 Jul 2009 02:17:54 +0000

This is a pretty nice solution, but for a high usage app/website, I would recommend adding a using statement for the Page object. Not properly disposing of it could lead to some serious memory fragmentation and performance problems.

By: rac

rac — Sat, 13 Jun 2009 07:13:11 +0000

I am working using this and I was wondering if you were ever able to get this to work using server controls in your usercontrol. I am stuck trying to figure out how to dynamically override(if possible) the Page’s VerifyRenderingInServerForm method. Is there a way to do this dynamically?

By: Mikkel Ovesen

Mikkel Ovesen — Mon, 08 Jun 2009 19:50:34 +0000

Ok, I will be posting a sample website in just a few minutes.

By: Bob

Bob — Sat, 06 Jun 2009 05:33:15 +0000

By: Mikkel Ovesen

Mikkel Ovesen — Fri, 08 May 2009 05:00:08 +0000

Thank you Kyle for the copy-paste version.

By: Kyle Corley

Kyle Corley — Fri, 08 May 2009 03:16:51 +0000

I went through the trouble of copying it for my own use, so here’s a more copy-and-paste-friendly version of the source above. Thanks again for the great ideas!
===========================================

public class AjaxUserControlHandler : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
// Get the path to the user control
string path = context.Request.Url.LocalPath;

// Intialize the pseudo page and user control
Page page = new Page();
UserControl viewControl = page.LoadControl(path) as UserControl;

// Display error if the user control was not found
if (viewControl == null)
{
context.Response.StatusCode = 404;
context.Response.Output.WriteLine("The requested url was not found");
return;
}

// Check existense of the AjaxEnabled attribute. Only add the AjaxEnabled attribut to
// user controls that is safe for direct calls
var type = viewControl.GetType();
var attributes = type.GetCustomAttributes(typeof (AjaxEnabledAttribute), true);
AjaxEnabledAttribute attribute = attributes.FirstOrDefault() as AjaxEnabledAttribute;

// If the attribute was not found, display an error
if (attribute == null)
{
context.Response.StatusCode = 403;
context.Response.Output.WriteLine("Access to the resource is not allowed");
return;
}

// Check if the request is valiud with regards to the requirements of the attribute.
// If not, display error
if ((attribute.Method == RequestMethodSupport.GET && context.Request.RequestType != "GET")
|| (attribute.Method == RequestMethodSupport.POST && context.Request.RequestType != "POST"))
{
context.Response.StatusCode = 403;
context.Response.Output.WriteLine(string.Format("The request method {0} is not allowed.", context.Request.RequestType));
return;
}

// Add user control to the pages control tree
page.Controls.Add(viewControl);

// Disable caching, remove this if you will allow client caching
context.Response.CacheControl = "No-Cache";

// Execute and return result to Output stream
context.Server.Execute(page, context.Response.Output, true);
}

public bool IsReusable
{
get { return true; }
}
}