I'd like to open the intelligence window without typing a character and then backspacing it. I can't seem to remember the shortcut for this. What is it?
Ctrl + Space?
Also, go to Tools -> Options -> Environment -> Keyboard or Default Keyboard Shortcuts in Visual Studio, you can then search for commands and see what is assigned to that (and remap).
Ctrl + Space for normal Intellisense, and Ctrl + Shift + Space for parameter Intellisense (e.g. to see what overloads are available in a method call which you've actually already filled in). I find the latter very handy :)
Ctrl + Space
If you have installed MSG Plus, then the problem is messenger lock keys, try to change them in msg plus and Intellisense will work again. Good Luck!
来源：https://stackoverflow.com/questions/145371/whats-the-default-intellisense-shortcut-in-vs2008