Visual Studio does not throw a warning during build for events marked Obsolete
This article describes the issue where Microsoft Visual Studio doesn't throw a warning during build for events marked
Original product version: Visual Studio Professional 2010, Visual Studio Premium 2012
Original KB number: 2832705
You have a C# Class library project with a class containing an event and you marked the event with the
Obsolete attribute. When you add reference to this class library in other project, for example a Console application and subscribe to that event, no warning is generated in the latter project.
Typically a warning CS0618 should be generated during compilation in Visual Studio when a method, event or property is marked with the
Obsolete attribute is applicable to all program elements except assemblies, modules, parameters or return values and works as expected.
This is a known issue with C# compiler.
This issue is observed in all editions of Visual Studio.