Daniel is completely correct in his description of enums. One additional note -- if you do wish to validate enum values, validate them only when it makes sense to do so. In other words, validate them only when they are generated through some means other than identifying a member of the enum (which is guaranteed to be valid) such as casting from an integer, etc.
Also, if you must validate the range of an enum value, consider using Enum.IsDefined. This does exactly what you want, and is also amenable to static analysis, either using SA tools, or running within very smart CLR implementations. -- arlie -----Original Message----- From: Moderated discussion of advanced .NET topics. [mailto:[EMAIL PROTECTED] On Behalf Of Daniel O'Connell Sent: Friday, April 09, 2004 2:56 PM To: [EMAIL PROTECTED] Subject: Re: [ADVANCED-DOTNET] Enumeration bounds checking? Because it's perfectly legal as far as the CLR is concerned. An enum is effectively an integral primitive that is treated slightly differently by the runtime. Any valid value for the primitive type is a valid value for the enum. By not limiting the enum to a set of values, it's possible to support scenarios where unknown enum values can be ignored or where flags with unknown bits set can exist. If it's important in your application you can perform checking yourself pretty easily without bogging down all uses of enums with needless value checking. > -----Original Message----- > From: Moderated discussion of advanced .NET topics. [mailto:ADVANCED- > [EMAIL PROTECTED] On Behalf Of Michael Sawczyn > Sent: Thursday, April 08, 2004 3:35 PM > To: [EMAIL PROTECTED] > Subject: [ADVANCED-DOTNET] Enumeration bounds checking? > > This is curious, and not covered in the C# language spec that I can find. > There appears not to be bounds checking invoked when enums are passed > as parameters. The following compiles and runs successfully. Any > thoughts as to why this would not be a language defect? > > public enum E > { > E1, > E2 > }; > > class Class1 > { > static void Main() > { > foo((E)50); // should throw runtime exception? > } > > static void foo(E e) > { > System.Console.Out.WriteLine(e); > } > } > > =================================== > This list is hosted by DevelopMentorR http://www.develop.com Some > .NET courses you may be interested in: > > NEW! Guerrilla ASP.NET, 17 May 2004, in Los Angeles > http://www.develop.com/courses/gaspdotnetls > > View archives and manage your subscription(s) at > http://discuss.develop.com =================================== This list is hosted by DevelopMentor http://www.develop.com Some .NET courses you may be interested in: NEW! Guerrilla ASP.NET, 17 May 2004, in Los Angeles http://www.develop.com/courses/gaspdotnetls View archives and manage your subscription(s) at http://discuss.develop.com =================================== This list is hosted by DevelopMentorŪ http://www.develop.com Some .NET courses you may be interested in: NEW! Guerrilla ASP.NET, 17 May 2004, in Los Angeles http://www.develop.com/courses/gaspdotnetls View archives and manage your subscription(s) at http://discuss.develop.com
