Is there a way to check if int is legal enum in C#?

Question

I've read a few SO posts and it seems most basic operation is missing.

public enum LoggingLevel {     Off = 0,     Error = 1,     Warning = 2,     Info = 3,     Debug = 4,     Trace = 5 };  if (s == "LogLevel") {     _log.LogLevel = (LoggingLevel)Convert.ToInt32("78");     _log.LogLevel = (LoggingLevel)Enum.Parse(typeof(LoggingLevel), "78");     _log.WriteDebug(_log.LogLevel.ToString()); } 

This causes no exceptions, it's happy to store 78. Is there a way to validate a value going into an enum?

Answer 1

Check out Enum.IsDefined

Usage:

if(Enum.IsDefined(typeof(MyEnum), value))     MyEnum a = (MyEnum)value;  

This is the example from that page:

using System;     [Flags] public enum PetType {    None = 0, Dog = 1, Cat = 2, Rodent = 4, Bird = 8, Reptile = 16, Other = 32 };  public class Example {    public static void Main()    {       object value;            // Call IsDefined with underlying integral value of member.       value = 1;       Console.WriteLine("{0}: {1}", value, Enum.IsDefined(typeof(PetType), value));       // Call IsDefined with invalid underlying integral value.       value = 64;       Console.WriteLine("{0}: {1}", value, Enum.IsDefined(typeof(PetType), value));       // Call IsDefined with string containing member name.       value = "Rodent";       Console.WriteLine("{0}: {1}", value, Enum.IsDefined(typeof(PetType), value));       // Call IsDefined with a variable of type PetType.       value = PetType.Dog;       Console.WriteLine("{0}: {1}", value, Enum.IsDefined(typeof(PetType), value));       value = PetType.Dog | PetType.Cat;       Console.WriteLine("{0}: {1}", value, Enum.IsDefined(typeof(PetType), value));       // Call IsDefined with uppercase member name.             value = "None";       Console.WriteLine("{0}: {1}", value, Enum.IsDefined(typeof(PetType), value));       value = "NONE";       Console.WriteLine("{0}: {1}", value, Enum.IsDefined(typeof(PetType), value));       // Call IsDefined with combined value       value = PetType.Dog | PetType.Bird;       Console.WriteLine("{0:D}: {1}", value, Enum.IsDefined(typeof(PetType), value));       value = value.ToString();       Console.WriteLine("{0:D}: {1}", value, Enum.IsDefined(typeof(PetType), value));    } } 

The example displays the following output:

//       1: True //       64: False //       Rodent: True //       Dog: True //       Dog, Cat: False //       None: True //       NONE: False //       9: False //       Dog, Bird: False