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。
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();
}
我很清楚这个问题已经被回答了,而且OP已经对接受的答案感到满意。但我发现大多数答案,包括公认的答案,都有点复杂。
我有一个项目给了我这样的情况,我能够以这种方式实现它。
首先,你必须考虑枚举名称的大小写:
public enum AuthenticationMethod
{
Forms = 1,
WindowsAuthentication = 2,
SingleSignOn = 3
}
然后,有这个扩展:
using System.Text.RegularExpression;
public static class AnExtension
{
public static string Name(this Enum value)
{
string strVal = value.ToString();
try
{
return Regex.Replace(strVal, "([a-z])([A-Z])", "$1 $2");
}
catch
{
}
return strVal;
}
}
通过这种方法,您可以将每个枚举名称转换为字符串表示形式,每个单词用空格分隔。例:
AuthenticationMethod am = AuthenticationMethod.WindowsAuthentication;
MessageBox.Show(am.Name());
这里有很多很棒的答案,但在我的情况下,并没有解决我想要的“字符串enum”,这是:
可用在switch语句中,例如switch(myEnum)
可以在函数参数中使用,例如foo(myEnum类型)
可以引用,例如myEnum。FirstElement
我可以使用字符串,例如foo("FirstElement") == foo(myenumer .FirstElement)
1、2和4实际上可以用一个字符串的c#类型定义来解决(因为字符串在c#中是可切换的)
3可以通过静态const字符串来求解。所以如果你有同样的需求,这是最简单的方法:
public sealed class Types
{
private readonly String name;
private Types(String name)
{
this.name = name;
}
public override String ToString()
{
return name;
}
public static implicit operator Types(string str)
{
return new Types(str);
}
public static implicit operator string(Types str)
{
return str.ToString();
}
#region enum
public const string DataType = "Data";
public const string ImageType = "Image";
public const string Folder = "Folder";
#endregion
}
这允许例如:
public TypeArgs(Types SelectedType)
{
Types SelectedType = SelectedType
}
and
public TypeObject CreateType(Types type)
{
switch (type)
{
case Types.ImageType:
//
break;
case Types.DataType:
//
break;
}
}
CreateType可以用字符串或类型调用。然而,缺点是任何字符串都是自动有效的enum,这可以被修改,但它将需要某种init函数…或者可能使它们显式转换内部?
现在,如果一个int值对你来说很重要(也许是比较速度),你可以使用Jakub Šturc的一些想法,做一些疯狂的事情,这是我的尝试:
public sealed class Types
{
private static readonly Dictionary<string, Types> strInstance = new Dictionary<string, Types>();
private static readonly Dictionary<int, Types> intInstance = new Dictionary<int, Types>();
private readonly String name;
private static int layerTypeCount = 0;
private int value;
private Types(String name)
{
this.name = name;
value = layerTypeCount++;
strInstance[name] = this;
intInstance[value] = this;
}
public override String ToString()
{
return name;
}
public static implicit operator Types(int val)
{
Types result;
if (intInstance.TryGetValue(val, out result))
return result;
else
throw new InvalidCastException();
}
public static implicit operator Types(string str)
{
Types result;
if (strInstance.TryGetValue(str, out result))
{
return result;
}
else
{
result = new Types(str);
return result;
}
}
public static implicit operator string(Types str)
{
return str.ToString();
}
public static bool operator ==(Types a, Types b)
{
return a.value == b.value;
}
public static bool operator !=(Types a, Types b)
{
return a.value != b.value;
}
#region enum
public const string DataType = "Data";
public const string ImageType = "Image";
#endregion
}
但是当然"Types bob = 4;"是没有意义的,除非你先对它们进行初始化,这就有点失败了……
但理论上a型== b型会更快…