Custom ChartImageHandler is not called after upgrading from 3.5 to 4.0

Question

I recently upgraded my website (source code here) from 3.5 to 4.0.  I changed all the references in web.config to point to 4.0, as discussed here.   I have a custom handler written (to deal with web farm scenario on Azure) that looks like this:

    <add key="ChartImageHandler" value="handler=ArchivistWeb.Helpers.ChartImageHandler, ArchivistWeb"/>

However, when I run the app, the handler does not get picked up and it appears that the .dll just loads the default value for ChartImageHandler.   It never finds my handler.  Is there something else I need to do in the .NET 4.0 version to register my handler? 

Answer 1

I've no experience with custom chart image handlers so I'll just throw in a link to this thread.

It looks like you probably should be getting an error if the handler is not found. Also the format of the AssemblyQualifiedName looks slightly different from what the answer in the linked thread suggests.

Answer 2

Right, that thread is from .NET 3.5, which works fine. It is 4.0 which doesn't work. Assembly qualified name is fine.  Yes, you'd think it would blow up, but instead it is just calling the default setting and never even looking for my ChartImageHandler...

Answer 3

turns out that this is caused by the somewhat kludgy way I'm using WebForms inside MVC to get the image map (tooltips, etc.) to work. currently exploring no longer doing things that way and using this methodology instead: http://geekswithblogs.net/DougLampe/archive/2011/01/23/charts-in-asp.net-mvc-2-with-drill-down.aspx