ASP.Net AJAX and MCMS

Posted 08 July 2008, 23:15 | by | | Perma-link

Ok, this one's pretty easy really, Initially we were just running with Stefan Großner's tips and code samples for using friendly URLs everywhere, and his hints on How to enable AJAX with MCMS and ASP.Net 2.0.

This was generally working fine for us, the page was requested by the ScriptManager calls, the ScriptManager in the master page hooked into the request, read the query strings it was looking for, rendered out the correct JavaScript, and stopped the page execution - all as you'd expect.

However, as development of the site progressed, we then built a control that allowed us to show or hide its child controls based on whether a MCMS placeholder on the posting contained any content - for example, we have an article page that can optionally display an image, and the image can optionally have a caption appearing below it - if there's no image, then everything under it should naturally float up the page, and the same for no caption. As there's a certain amount of html and css needed to get this to work, it's nicer if this isn't rendered out if there's no image, hence this control. However, to get this to work properly, with nested conditional controls, we needed to do our magic in the AddParsedSubObject method which runs before the ScriptManager did it's stuff - and if you try and call the posting templated directly without a CMS context (all those NR querystrings) and then try and access the CMS objects it all goes belly up.

Thankfully, there's a simpe solution - the ToolkitScriptManager that is part of the ASP.Net AJAX Control Extensions has a very nice property on it: CombineScriptsHandlerUrl - by default the ToolkitScriptManager will attempt to combine all the required scripts into one nice big script, instead of lots of little ones - and this property tells it what page it should call to do this - I think technically you should use an .ashx page for this - although an .aspx page with the ToolkitScriptManager on it works just as well - there's some detailed information on the CombineScriptsHandlerUrl here. Setting this property to a non-CMS page has fixed all our problems.

Another nice feature in ASP.Net 3.5 is the ScriptManagerProxy - this allows you to place a ScriptManager (or ToolkitScriptManager) on your master page and then place the ScriptManagerProxy in the page or user control as required. This means that to register a client script block instead of writing something like:

var scriptManager = ToolkitScriptManager.GetCurrent(Page);
if (null != scriptManager)
  { scriptManager.RegisterClientScriptBlock([...]); }

You can just call the local ScriptManagerProxy with the same methods. All very nice.


Part of the Series: The joys of using .Net 2.0, .Net 3.0 and .Net 3.5 with MCMS

Filed under: AJAX, ASP.NET, MCMS