我读过一些SO帖子，似乎最基本的操作都缺失了。
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());
}
这不会导致异常，它很乐意存储78。是否有一种方法来验证进入枚举的值?
当前回答
Use:
Enum.IsDefined ( typeof ( Enum ), EnumValue );
其他回答
规范的答案是Enum。IsDefined，但这是a:在一个紧密循环中使用有点慢，b:对[Flags]枚举无效。
就我个人而言，我不会再担心这个问题，只要适当地转换一下，记住:
如果不识别所有内容(只是不做任何事情)是可以的，那么就不要添加默认值:(或使用空默认值:解释原因) 如果有一个明智的默认行为，把它放在默认: 否则，处理你知道的那些，并对其余的抛出异常:
像这样:
switch(someflag) {
case TriBool.Yes:
DoSomething();
break;
case TriBool.No:
DoSomethingElse();
break;
case TriBool.FileNotFound:
DoSomethingOther();
break;
default:
throw new ArgumentOutOfRangeException("someflag");
}
签出Enum。IsDefined
用法:
if(Enum.IsDefined(typeof(MyEnum), value))
MyEnum a = (MyEnum)value;
这是那一页的例子:
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));
}
}
使用实例显示如下信息:
// 1: True
// 64: False
// Rodent: True
// Dog: True
// Dog, Cat: False
// None: True
// NONE: False
// 9: False
// Dog, Bird: False
使用Enum.IsDefined。
为了处理[Flags]，你也可以使用c# Cookbook中的这个解决方案:
首先，添加一个新的ALL值到你的枚举:
[Flags]
enum Language
{
CSharp = 1, VBNET = 2, VB6 = 4,
All = (CSharp | VBNET | VB6)
}
然后，检查值是否在ALL中:
public bool HandleFlagsEnum(Language language)
{
if ((language & Language.All) == language)
{
return (true);
}
else
{
return (false);
}
}
一种方法是依赖于强制转换和枚举到字符串的转换。当将int转换为Enum类型时，int要么被转换为相应的Enum值，要么如果没有为int定义Enum值，则结果Enum仅包含int作为值。
enum NetworkStatus{
Unknown=0,
Active,
Slow
}
int statusCode=2;
NetworkStatus netStatus = (NetworkStatus) statusCode;
bool isDefined = netStatus.ToString() != statusCode.ToString();
没有对任何边缘情况进行测试。
