我有以下列举:
public enum AuthenticationMethod
{
FORMS = 1,
WINDOWSAUTHENTICATION = 2,
SINGLESIGNON = 3
}
然而问题是，当我请求AuthenticationMethod时，我需要“FORMS”这个词。表单而不是id
对于这个问题，我找到了以下解决方案(链接):
首先，我需要创建一个自定义属性“StringValue”:
public class StringValue : System.Attribute
{
private readonly string _value;
public StringValue(string value)
{
_value = value;
}
public string Value
{
get { return _value; }
}
}
然后我可以将这个属性添加到我的枚举器中:
public enum AuthenticationMethod
{
[StringValue("FORMS")]
FORMS = 1,
[StringValue("WINDOWS")]
WINDOWSAUTHENTICATION = 2,
[StringValue("SSO")]
SINGLESIGNON = 3
}
当然，我需要一些东西来检索StringValue:
public static class StringEnum
{
public static string GetStringValue(Enum value)
{
string output = null;
Type type = value.GetType();
//Check first in our cached results...
//Look for our 'StringValueAttribute'
//in the field's custom attributes
FieldInfo fi = type.GetField(value.ToString());
StringValue[] attrs =
fi.GetCustomAttributes(typeof(StringValue),
false) as StringValue[];
if (attrs.Length > 0)
{
output = attrs[0].Value;
}
return output;
}
}
很好，现在我已经有了工具来获取枚举器的字符串值。
然后我可以这样使用它:
string valueOfAuthenticationMethod = StringEnum.GetStringValue(AuthenticationMethod.FORMS);
好的，现在所有这些工作就像一个魅力，但我发现它有很多工作。我想知道有没有更好的解决办法。
我还尝试了一些字典和静态属性，但这也不是更好。
我的变体
public struct Colors
{
private String current;
private static string red = "#ff0000";
private static string green = "#00ff00";
private static string blue = "#0000ff";
private static IList<String> possibleColors;
public static Colors Red { get { return (Colors) red; } }
public static Colors Green { get { return (Colors) green; } }
public static Colors Blue { get { return (Colors) blue; } }
static Colors()
{
possibleColors = new List<string>() {red, green, blue};
}
public static explicit operator String(Colors value)
{
return value.current;
}
public static explicit operator Colors(String value)
{
if (!possibleColors.Contains(value))
{
throw new InvalidCastException();
}
Colors color = new Colors();
color.current = value;
return color;
}
public static bool operator ==(Colors left, Colors right)
{
return left.current == right.current;
}
public static bool operator !=(Colors left, Colors right)
{
return left.current != right.current;
}
public bool Equals(Colors other)
{
return Equals(other.current, current);
}
public override bool Equals(object obj)
{
if (ReferenceEquals(null, obj)) return false;
if (obj.GetType() != typeof(Colors)) return false;
return Equals((Colors)obj);
}
public override int GetHashCode()
{
return (current != null ? current.GetHashCode() : 0);
}
public override string ToString()
{
return current;
}
}
代码看起来有点丑，但是这个结构体的用法很有代表性。
Colors color1 = Colors.Red;
Console.WriteLine(color1); // #ff0000
Colors color2 = (Colors) "#00ff00";
Console.WriteLine(color2); // #00ff00
// Colors color3 = "#0000ff"; // Compilation error
// String color4 = Colors.Red; // Compilation error
Colors color5 = (Colors)"#ff0000";
Console.WriteLine(color1 == color5); // True
Colors color6 = (Colors)"#00ff00";
Console.WriteLine(color1 == color6); // False
此外，我认为，如果需要大量这样的枚举，可能会使用代码生成(例如T4)。
试试type-safe-enum模式。
public sealed class AuthenticationMethod {
private readonly String name;
private readonly int value;
public static readonly AuthenticationMethod FORMS = new AuthenticationMethod (1, "FORMS");
public static readonly AuthenticationMethod WINDOWSAUTHENTICATION = new AuthenticationMethod (2, "WINDOWS");
public static readonly AuthenticationMethod SINGLESIGNON = new AuthenticationMethod (3, "SSN");
private AuthenticationMethod(int value, String name){
this.name = name;
this.value = value;
}
public override String ToString(){
return name;
}
}
更新
显式(或隐式)类型转换可以通过
adding static field with mapping
private static readonly Dictionary<string, AuthenticationMethod> instance = new Dictionary<string,AuthenticationMethod>();
n.b. In order that the initialisation of the the "enum member" fields doesn't throw a NullReferenceException when calling the instance constructor, be sure to put the Dictionary field before the "enum member" fields in your class. This is because static field initialisers are called in declaration order, and before the static constructor, creating the weird and necessary but confusing situation that the instance constructor can be called before all static fields have been initialised, and before the static constructor is called.
filling this mapping in instance constructor
instance[name] = this;
and adding user-defined type conversion operator
public static explicit operator AuthenticationMethod(string str)
{
AuthenticationMethod result;
if (instance.TryGetValue(str, out result))
return result;
else
throw new InvalidCastException();
}
我发现的Enums国际化或从各自的资源文件获取Enums文本的方法是通过继承DescriptionAttribute类创建一个属性类
public class EnumResourceAttribute : DescriptionAttribute
{
public Type ResourceType { get; private set; }
public string ResourceName { get; private set; }
public int SortOrder { get; private set; }
public EnumResourceAttribute(Type ResourceType,
string ResourceName,
int SortOrder)
{
this.ResourceType = ResourceType;
this.ResourceName = ResourceName;
this.SortOrder = SortOrder;
}
}
创建另一个Static类，为GetString和GetString提供扩展方法。
public static class EnumHelper
{
public static string GetString(this Enum value)
{
EnumResourceAttribute ea =
(EnumResourceAttribute)value.GetType().GetField(value.ToString())
.GetCustomAttributes(typeof(EnumResourceAttribute), false)
.FirstOrDefault();
if (ea != null)
{
PropertyInfo pi = ea.ResourceType
.GetProperty(CommonConstants.ResourceManager);
if (pi != null)
{
ResourceManager rm = (ResourceManager)pi
.GetValue(null, null);
return rm.GetString(ea.ResourceName);
}
}
return string.Empty;
}
public static IList GetStrings(this Type enumType)
{
List<string> stringList = new List<string>();
FieldInfo[] fiArray = enumType.GetFields();
foreach (FieldInfo fi in fiArray)
{
EnumResourceAttribute ea =
(EnumResourceAttribute)fi
.GetCustomAttributes(typeof(EnumResourceAttribute), false)
.FirstOrDefault();
if (ea != null)
{
PropertyInfo pi = ea.ResourceType
.GetProperty(CommonConstants.ResourceManager);
if (pi != null)
{
ResourceManager rm = (ResourceManager)pi
.GetValue(null, null);
stringList.Add(rm.GetString(ea.ResourceName));
}
}
}
return stringList.ToList();
}
}
在Enum的元素上，你可以这样写:
public enum Priority
{
[EnumResourceAttribute(typeof(Resources.AdviceModule), Resources.ResourceNames.AdviceCreateAdviceExternaPriorityMemberHigh, 1)]
High,
[EnumResourceAttribute(typeof(Resources.AdviceModule), Resources.ResourceNames.AdviceCreateAdviceExternaPriorityMemberRoutine, 2)]
Routine
}
Where Resources.ResourceNames.AdviceCreateAdviceExternaPriorityMemberHigh &
resources . resourcename . advicecreateadviceexternaprioritymemberroutine是资源文件中的常量，或者你可以说字符串，其值可以在不同的文化中可用。
如果你在MVC架构中实现你的web应用程序，那么创建一个属性
private IList result;
public IList Result
{
get
{
result = typeof(Priority).GetStrings();
return result;
}
}
在你的.cshtml文件中，你可以像这样将枚举绑定到你的下拉列表:
@Html.DropDownListFor(model => Model.vwClinicalInfo.Priority, new SelectList(Model.Result))
谢谢
Ratnesh
可以使用ToString()引用名称而不是值
Console.WriteLine("Auth method: {0}", AuthenticationMethod.Forms.ToString());
文档在这里:
http://msdn.microsoft.com/en-us/library/16c1xs4z.aspx
.．.如果你在Pascal情况下命名你的枚举(如ThisIsMyEnumValue = 1等)，那么你可以使用一个非常简单的正则表达式来打印友好的形式:
static string ToFriendlyCase(this string EnumString)
{
return Regex.Replace(EnumString, "(?!^)([A-Z])", " $1");
}
可以很容易地从任何字符串调用:
Console.WriteLine("ConvertMyCrazyPascalCaseSentenceToFriendlyCase".ToFriendlyCase());
输出:
把我疯狂的帕斯卡格句转换成友好格句
这节省了在房子周围运行创建自定义属性并将它们附加到枚举或使用查找表将枚举值与友好字符串结合，最好的是它是自我管理的，可以用于任何Pascal Case字符串，这是无限可重用的。当然，它不允许您使用与解决方案提供的枚举不同的友好名称。
不过，我确实喜欢你针对更复杂场景的原始解决方案。你可以把你的解决方案更进一步，让你的GetStringValue成为你的枚举的扩展方法，然后你就不需要像StringEnum.GetStringValue…
public static string GetStringValue(this AuthenticationMethod value)
{
string output = null;
Type type = value.GetType();
FieldInfo fi = type.GetField(value.ToString());
StringValue[] attrs = fi.GetCustomAttributes(typeof(StringValue), false) as StringValue[];
if (attrs.Length > 0)
output = attrs[0].Value;
return output;
}
然后你可以直接从你的枚举实例中访问它:
Console.WriteLine(AuthenticationMethod.SSO.GetStringValue());
