Visual Studio Code IntelliSense suggestions don't pop up automatically

Question

I followed the install instructions in https://code.visualstudio.com, but when I write C# code, the IntelliSense suggestions don\'t pop up automatically, so I must trigger i

Answer 1

To activate IntelliSense on a .NET project:

1. Open project folder: File->Open folder...
2. Click on the flame on your bottom left corner, pick your project
3. IntelliSense activated!

From what I've seen, IntelliSense cannot be activated on a .cs file alone. (See @natemcmaster's answer).