Many users may face a common issue when IntelliSense is not working in Visual Studio. Here are some solutions which can be tried to solve the problem.
Solution 1
Go to Tools->Options->Text Editor-> All Languages->General
Enable "Auto List Members" and "Parameter Information"
Solution 2
Now "Restart the Visual Studio" and Try Again (mostly works).
Solution 3
Just delete the folder "ReflectedSchemas". Here, location depends on Visual Studio Version
%AppData%\Microsoft\VisualStudio\11.0\ReflectedSchemas -For VS 13
Solution 4
Next, reset the Settings from the following location.
Tools->Import and Export settings->Reset all settings.
Next ->
Solution 4
Check if CS.Proj is corrupted or not. If this is the case, then try to add back or fix it.
Solution 5
Run Visual Studio As Administrator
Solution 6
Goto Edit > IntelliSense > Refresh Local Cache
Solution 7
Delete .suo file in Your Project
Solution 8
Delete .psess File in your Project
Solution 9
Re-Install Visual Studio ( Backup everything)
Please comment below for any help or you can also give your own solutions that you encountered and solved.