Ajax is a flexible and powerful technology, but sometimes “With great power comes great responsibility” . And also some kind of fragility and sensitivity to external factors. In this case browsing the application worked somehow fine, but triggering a partial postback we were getting the following error on the browser: The message received from the…


HoverNodeStyle not applied with partial postback

The TreeView control has built-in Ajax capabilities when it comes to dynamically fill it nodes; this is done through the PopulateNodesFromClient: Sometimes, it is not practical to statically predefine the tree structure due to data size or custom content that depends on user input. Because of this, the TreeView control supports dynamic node population. When…


WebResource.axd or ScriptResource.axd not working

Http compression with client-side scripting should be handled with care. The problem can have different symptoms and manifest in different ways, but essentially it has a common root cause and I have already discussed some of the aspects (for example see here and here). This time the customer whom reported the problem was using Forms…


Very slow TreeView in UpdatePanel

This is what we got couple of weeks ago: an Ajax enabled ASP.NET web application was using a TreeView control within an UpdatePanel to show a complex tree of hierarchical data (the sample we got had more than 2.000 nodes with varying degrees of nesting). The result was that browsing the tree within IE was…


The message received from the server could not be parsed

Again on the Ajax-compression subject (see here and here), here’s another error I got recently: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, HttpModules, or server trace is enabled. The customer was using the GZipStream…


Ajax resource intermittently not accessible (http compression)

A few days before Christmas I had a case where the customer was intermittently getting troubles with his javascript/Ajax resource; as usual everything was working fine on the development machine, but when moved on the production server the application started throwing some client side javascript exceptions like "myVar is undefined" which means that the Ajax…


Don’t let IE local cache drive you crazy!

I stumbled across this issue multiple times during my life of web developer (which begun about 10 years ago), it appeared every now and then to complicate things when I was in the middle of a heavy debugging sessions and doing frequent changes to my pages; I was expecting some kind of results but despite…


Inconsistent Javascript behavior in Internet Explorer

My colleague Stefano had this case a few weeks ago, but since he has not a blog (yet ) and I’ve been partially involved in it, I thought this might be interesting to share… So, here is the story: the customer wanted to disable a button inside the onBlur event of a textbox through client-side Javascript….