Visual Studio warning level meanings?

On the build tab in a Web Application project I have a setting called "Warning Level". I can set a value from 0 to 4. What do these values mean? Will a value of 0 be more strict and generate more warnings, or vice versa? I haven't been able to find any documentation on it yet, but perhaps I'm looking in the wrong place.

Solution 1:

This link shows you the definitions of the warning levels (I'm assuming you are using C# code in your web project). Level 4 is the most strict.

• 0: Turns off emission of all warning messages.
• 1: Displays severe warning messages.
• 2: Displays level 1 warnings plus certain, less-severe warnings, such as warnings about hiding class members.
• 3: Displays level 2 warnings plus certain, less-severe warnings, such as warnings about expressions that always evaluate to true or false.
• 4: Displays all level 3 warnings plus informational warnings. This is the default warning level at the command line.
• 5: Displays level 4 warnings plus additional warnings from the compiler shipped with C# 9.0.

Anything greater than 5 is treated as 5.

Solution 2:

Higher is stricter. It can be annoying to see all the warnings that may or may not mean much to your app, but taking the time to clear them up can teach you a lot.

Solution 3:

You can check Microsoft's levels here. Level 0 is essentially none while level 4 will be the most strict.

Solution 4:

0 turns off warnings completely, while 4 is the most verbose level. See the documentation here which has the same warning levels.