Why can I parse invalid values to an Enum in .NET?
Why is this even possible? Is it a bug?
using System;
public class InvalidEnumParse
{
public enum Number
{
One,
Two,
Three,
Four
}
public static void Main()
{
string input = "761";
Number number = (Number)Enum.Parse(typeof(Number), input);
Console.WriteLine(number); //outputs 761
开发者_JAVA百科 }
}
That's just the way enums work in .NET. The enum isn't a restrictive set of values, it's really just a set of names for numbers (and a type to collect those names together) - and I agree that's a pain sometimes.
If you want to test whether a value is really defined in the enum, you can use Enum.IsDefined
after parsing it. If you want to do this in a more type-safe manner, you might want to look at my Unconstrained Melody project which contains a bunch of constrained generic methods.
If you have a enum
with [Flags]
attribute, you can have any value combination. For instance:
[Flags]
enum Test
{
A = 1,
B = 2,
C = 4,
D = 8
}
You could to do this:
Test sample = (Test)7;
foreach (Test test in Enum.GetValues(typeof(Test)))
{
Console.WriteLine("Sample does{0} contains {1}",
(sample & test) == test ? "": " not", test);
}
精彩评论