This is a strange one that I experienced a few months ago and feel compelled to write about it. I had written a visual web part for SharePoint 2010, and installed it during out of business hours. I added it to a page and then waited for the next day where my work colleague was going to provision the necessary lists and libraries for the web part to use.
Next day – after my colleague had provisioned the other objects that the web part would use – the page with the web part was displaying without any errors, and it seemed to be installed properly but none of the code behind was being executed to read from the lists that were provisioned. The web part was built using the ASP.Net MultiView component. We went through checking:-
1) the logs – nothing there
2) using fiddler – nothing unusual
3) GAC was ok.
4) Event Viewer – nothing there, no errors
After exhausting all options, and finding no errors being generated, we decided that maybe we need to install again the web part. So after close of business, we re-installed the webpart on the SharePoint server, and guess what ? it started working !!!!
Conclusions drawn from this experience is that if something like this happens to you – and you find no errors in the normal places, then it probably means just installing the web part again.
Update:- by re-installing I had carried out an Update-SPSolution in PowerShell.