Intellisense.

Intellisense in visual studio decided to turn itself off for my project.

The following blog post tells you how to fix it...

Intellisense not working in Visual Studio...
"IntelliSense is Microsoft's implementation of autocompletion, best known for its use in the Microsoft Visual Studio integrated development environment. In addition to completing the symbol names the programmer is typing, IntelliSense serves as documentation and disambiguation for variable names, functions and methods using metadata-based reflection." (Wikipedia)
So, I can't quite remember when exactly Intellisense stopped working for me in Visual Studio 2008, but I know I have been without (automatic) Intellisense for quite a while.When typing a dot after an object or method, it used to just show up automatically... I could however have it come up by pressing and eventually got in the habit of just doing that when I needed it, without attempting to find out exactly why it was broken in the first place...
So, several months later, I stumble upon an entry by Richard Fennell, who explains how to fix it. I thought I'd post it for when it breaks again, I know where to find the answer...

In Visual Studio 2008, select Tools > Options > Text Editor > All Languages. Ensure that the checkboxes in the Statement Completion section are actively checked (not grayed out).
That is it!. Click Ok and try it.

By Miguel Moreno
http://miguelmoreno.net/post/Intellisense-not-working-in-Visual-Studio.aspx