C# Parse从Enum获取对象值,然后必须将对象值更改为特定的Enum值。可以使用Convert.ChangeType转换为枚举值。请看一下下面的代码片段 public T ConvertStringValueToEnum<T>(string valueToParse){ return Convert.ChangeType(Enum.Parse(typeof(T), valueToParse, true), typeof(T)); } public T ConvertStringValueToEnum(字符串值ToParse){ 返回Convert.ChangeType(Enum.Parse(typeof(T),valueToParse,true),typeof(T)); }
尝试以下示例:C# Parse从Enum获取对象值,然后必须将对象值更改为特定的Enum值。可以使用Convert.ChangeType转换为枚举值。请看一下下面的代码片段 public T ConvertStringValueToEnum<T>(string valueToParse){ return Convert.ChangeType(Enum.Parse(typeof(T), valueToParse, true), typeof(T)); } public T ConvertStringValueToEnum(字符串值ToParse){ 返回Convert.ChangeType(Enum.Parse(typeof(T),valueToParse,true),typeof(T)); },c#,string,enums,C#,String,Enums,尝试以下示例: public static T GetEnum<T>(string model) { var newModel = GetStringForEnum(model); if (!Enum.IsDefined(typeof(T), newModel)) { return (T)Enum.Parse(typeof(T), "None", true); } r
public static T GetEnum<T>(string model)
{
var newModel = GetStringForEnum(model);
if (!Enum.IsDefined(typeof(T), newModel))
{
return (T)Enum.Parse(typeof(T), "None", true);
}
return (T)Enum.Parse(typeof(T), newModel.Result, true);
}
private static Task<string> GetStringForEnum(string model)
{
return Task.Run(() =>
{
Regex rgx = new Regex("[^a-zA-Z0-9 -]");
var nonAlphanumericData = rgx.Matches(model);
if (nonAlphanumericData.Count < 1)
{
return model;
}
foreach (var item in nonAlphanumericData)
{
model = model.Replace((string)item, "");
}
return model;
});
}
publicstatict GetEnum(字符串模型)
{
var newModel=GetStringForEnum(模型);
如果(!Enum.IsDefined(typeof(T),newModel))
{
返回(T)Enum.Parse(typeof(T),“无”,true);
}
返回(T)Enum.Parse(typeof(T),newModel.Result,true);
}
私有静态任务GetStringForEnum(字符串模型)
{
返回任务。运行(()=>
{
正则表达式rgx=新正则表达式(“[^a-zA-Z0-9-]”);
var nonAlphanumericData=rgx.Matches(模型);
if(非alphanumericData.Count<1)
{
收益模型;
}
foreach(非alphanumeric数据中的var项)
{
模型=模型。替换((字符串)项“”);
}
收益模型;
});
}
在此示例中,您可以发送每个字符串,并设置Enum
。如果您的Enum
具有所需的数据,请将其作为Enum
类型返回。
<Extension()>
Public Function ToEnum(Of TEnum)(ByVal value As String, ByVal defaultValue As TEnum) As TEnum
If String.IsNullOrEmpty(value) Then
Return defaultValue
End If
Return [Enum].Parse(GetType(TEnum), value, True)
End Function
公共函数ToEnum(共十个)(ByVal值为字符串,ByVal defaultValue为十个)为十个
如果String.IsNullOrEmpty(值),则
返回默认值
如果结束
返回[Enum].Parse(GetType(TEnum),value,True)
端函数
公共TEnum-ToEnum(此字符串值,TEnum-defaultValue){
if(string.IsNullOrEmpty(value))
返回默认值;
返回Enum.Parse(typeof(TEnum),value,true);}
不确定这是何时添加的,但在Enum类上现在有一个
Parse(stringValue)
与上述示例类似使用:
var MyStatus=Enum.Parse(“活动”)
或通过以下方式忽略套管:
var MyStatus=Enum.Parse(“active”,true)
以下是它使用的反编译方法:
[NullableContext(0)]
公共静态TEnum解析([Nullable(1)]字符串值),其中TEnum:struct
{
返回Enum.Parse(值,false);
}
[NullableContext(0)]
公共静态TEnum解析([Nullable(1)]字符串值,bool ignoreCase),其中TEnum:struct
{
十年结果;
Enum.TryParse(值、ignoreCase、true、out结果);
返回结果;
}
如果属性名称与您想要的名称不同(即语言差异),您可以这样做:
StatusEnum MyStatus = StatusEnum.Parse("Active");
enum Mood
{
Angry,
Happy,
Sad
}
// ...
Mood m = (Mood) Enum.Parse(typeof(Mood), "Happy", true);
Console.WriteLine("My mood is: {0}", m.ToString());
public enum Store : short
{
[Description("Rio Big Store")]
Rio = 1
}
MyType.cs
using System;
using System.Runtime.Serialization;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
[JsonConverter(typeof(StringEnumConverter))]
public enum MyType
{
[EnumMember(Value = "person")]
Person,
[EnumMember(Value = "annan_deltagare")]
OtherPerson,
[EnumMember(Value = "regel")]
Rule,
}
EnumExtensions.cs
using System;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
public static class EnumExtensions
{
public static TEnum ToEnum<TEnum>(this string value) where TEnum : Enum
{
var jsonString = $"'{value.ToLower()}'";
return JsonConvert.DeserializeObject<TEnum>(jsonString, new StringEnumConverter());
}
public static bool EqualsTo<TEnum>(this string strA, TEnum enumB) where TEnum : Enum
{
TEnum enumA;
try
{
enumA = strA.ToEnum<TEnum>();
}
catch
{
return false;
}
return enumA.Equals(enumB);
}
}
使用系统;
使用Newtonsoft.Json;
使用Newtonsoft.Json.Converters;
公共静态类枚举扩展
{
公共静态TEnum-ToEnum(此字符串值),其中TEnum:Enum
{
var jsonString=$“{value.ToLower()}”;
返回JsonConvert.DeserializeObject(jsonString,new StringEnumConverter());
}
公共静态bool EqualsTo(这个字符串strA,TEnum enumB),其中TEnum:Enum
{
细线;
尝试
{
enumA=strA.ToEnum();
}
抓住
{
返回false;
}
返回enumA.Equals(enumB);
}
}
Program.cs
public class Program
{
static public void Main(String[] args)
{
var myString = "annan_deltagare";
var myType = myString.ToEnum<MyType>();
var isEqual = myString.EqualsTo(MyType.OtherPerson);
//Output: true
}
}
公共类程序
{
静态公共void Main(字符串[]args)
{
var myString=“annan_deltagare”;
var myType=myString.ToEnum();
var isEqual=myString.EqualsTo(MyType.OtherPerson);
//输出:真
}
}
如果要在null或空时使用默认值(例如,从配置文件检索时,该值不存在),并在字符串或数字与任何枚举值不匹配时引发异常。但要注意提莫回答中的警告()
public static T ParseEnum(此字符串s,T defaultValue,bool ignoreCase=false)
其中T:struct,IComparable,IConvertible,IFormattable//如果C#>=7.3:struct,System.Enum
{
如果((s?长度±0)=0)
{
返回默认值;
}
var valid=Enum.TryParse(s,ignoreCase,out T res);
如果定义了(!valid | | |!Enum.IsDefined(typeof(T),res))
{
抛出新的InvalidOperationException(
$“{s}”不是枚举“{typeof(T).FullName}”!”的有效值;
}
返回res;
}
首先,您需要装饰您的枚举,如下所示:
StatusEnum MyStatus = StatusEnum.Parse("Active");
enum Mood
{
Angry,
Happy,
Sad
}
// ...
Mood m = (Mood) Enum.Parse(typeof(Mood), "Happy", true);
Console.WriteLine("My mood is: {0}", m.ToString());
public enum Store : short
{
[Description("Rio Big Store")]
Rio = 1
}
在.net 5中,我创建了以下扩展方法:
//The class also needs to be static, ok?
public static string GetDescription(this System.Enum enumValue)
{
FieldInfo fi = enumValue.GetType().GetField(enumValue.ToString());
DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(
typeof(DescriptionAttribute), false);
if (attributes != null && attributes.Length > 0) return attributes[0].Description;
else return enumValue.ToString();
}
现在,您可以在任何枚举中使用扩展方法
像这样:
var Desc = Store.Rio.GetDescription(); //Store is your Enum
如果绩效是重要的(总是重要的),那么Mckenzieg1给出的chk答案如下:@Avinash关于@Mckenzieg1的答案是正确的,但并不总是重要的。例如,如果您对每次分析都进行DB调用,那么担心枚举分析将是一种毫无意义的微观优化。@H.M.我认为扩展在这里并不合适-这是一种特殊情况,扩展将应用于每个字符串。如果你真的想这么做,那只是一个小小的改变。Enum.TryParse怎么样?很好。在上一个示例中,您需要where T:struct。如果代码已经包含描述,是否需要进行描述?好的,我这样做了:)我已经更新了它,将值作为对象,并将其转换为该方法内的字符串。通过这种方式,我可以使用int值.ToEnum而不是字符串。@SollyM我认为这是一个可怕的想法,因为这个扩展方法将应用于所有对象类型。两个扩展方法,一个用于字符串,一个用于int,在我看来会更干净、更安全。@Svish,没错。我这样做的唯一原因是因为我们的代码只在内部使用,我想避免编写2个扩展。由于我们唯一一次转换为Enum是使用string或int,所以我认为在其他方面没有问题。@S
/// <summary>
/// Parses string to TEnum without try/catch and .NET 4.5 TryParse()
/// </summary>
public static bool TryParseToEnum<TEnum>(string probablyEnumAsString_, out TEnum enumValue_) where TEnum : struct
{
enumValue_ = (TEnum)Enum.GetValues(typeof(TEnum)).GetValue(0);
if(!Enum.IsDefined(typeof(TEnum), probablyEnumAsString_))
return false;
enumValue_ = (TEnum) Enum.Parse(typeof(TEnum), probablyEnumAsString_);
return true;
}
StatusEnum myStatus;
Enum.TryParse("Active", out myStatus);
Enum.TryParse("Active", out StatusEnum myStatus);
public static T ToEnum<T>(this string value, bool ignoreCase = true)
{
return (T) Enum.Parse(typeof (T), value, ignoreCase);
}
FilterType filterType = type.ToEnum<FilterType>();
public static T ParseEnum<T>(string value, T defaultValue) where T : struct
{
try
{
T enumValue;
if (!Enum.TryParse(value, true, out enumValue))
{
return defaultValue;
}
return enumValue;
}
catch (Exception)
{
return defaultValue;
}
}
StatusEnum MyStatus = EnumUtil.ParseEnum("Active", StatusEnum.None);
StatusEnum MyStatus = Enum<StatusEnum>.Parse("Active");
public static T ParseEnum<T>(string value) //function declaration
{
return (T) Enum.Parse(typeof(T), value);
}
Importance imp = EnumUtil.ParseEnum<Importance>("Active"); //function call
using System;
class Program
{
enum PetType
{
None,
Cat = 1,
Dog = 2
}
static void Main()
{
// Possible user input:
string value = "Dog";
// Try to convert the string to an enum:
PetType pet = (PetType)Enum.Parse(typeof(PetType), value);
// See if the conversion succeeded:
if (pet == PetType.Dog)
{
Console.WriteLine("Equals dog.");
}
}
}
-------------
Output
Equals dog.
namespace System
{
public static class StringExtensions
{
public static bool TryParseAsEnum<T>(this string value, out T output) where T : struct
{
T result;
var isEnum = Enum.TryParse(value, out result);
output = isEnum ? result : default(T);
return isEnum;
}
}
}
using static Microsoft.VisualStudio.TestTools.UnitTesting.Assert;
using static System.Console;
private enum Countries
{
NorthAmerica,
Europe,
Rusia,
Brasil,
China,
Asia,
Australia
}
[TestMethod]
public void StringExtensions_On_TryParseAsEnum()
{
var countryName = "Rusia";
Countries country;
var isCountry = countryName.TryParseAsEnum(out country);
WriteLine(country);
IsTrue(isCountry);
AreEqual(Countries.Rusia, country);
countryName = "Don't exist";
isCountry = countryName.TryParseAsEnum(out country);
WriteLine(country);
IsFalse(isCountry);
AreEqual(Countries.NorthAmerica, country); // the 1rst one in the enumeration
}
enum Example
{
One = 1,
Two = 2,
Three = 3
}
var x = Enum.Parse("One,Two"); // x is now Three
public static bool TryParse<T>(string value, out T result)
where T : struct
{
var cacheKey = "Enum_" + typeof(T).FullName;
// [Use MemoryCache to retrieve or create&store a dictionary for this enum, permanently or temporarily.
// [Implementation off-topic.]
var enumDictionary = CacheHelper.GetCacheItem(cacheKey, CreateEnumDictionary<T>, EnumCacheExpiration);
return enumDictionary.TryGetValue(value.Trim(), out result);
}
private static Dictionary<string, T> CreateEnumDictionary<T>()
{
return Enum.GetValues(typeof(T))
.Cast<T>()
.ToDictionary(value => value.ToString(), value => value, StringComparer.OrdinalIgnoreCase);
}
private static Dictionary<Type, Dictionary<string, object>> dicEnum = new Dictionary<Type, Dictionary<string, object>>();
public static T ToEnum<T>(this string value, T defaultValue)
{
var t = typeof(T);
Dictionary<string, object> dic;
if (!dicEnum.ContainsKey(t))
{
dic = new Dictionary<string, object>();
dicEnum.Add(t, dic);
foreach (var en in Enum.GetValues(t))
dic.Add(en.ToString(), en);
}
else
dic = dicEnum[t];
if (!dic.ContainsKey(value))
return defaultValue;
else
return (T)dic[value];
}
using System.Runtime.Serialization;
public static TEnum ToEnum<TEnum>(this string value, TEnum defaultValue) where TEnum : struct
{
if (string.IsNullOrEmpty(value))
{
return defaultValue;
}
TEnum result;
var enumType = typeof(TEnum);
foreach (var enumName in Enum.GetNames(enumType))
{
var fieldInfo = enumType.GetField(enumName);
var enumMemberAttribute = ((EnumMemberAttribute[]) fieldInfo.GetCustomAttributes(typeof(EnumMemberAttribute), true)).FirstOrDefault();
if (enumMemberAttribute?.Value == value)
{
return Enum.TryParse(enumName, true, out result) ? result : defaultValue;
}
}
return Enum.TryParse(value, true, out result) ? result : defaultValue;
}
public enum OracleInstanceStatus
{
Unknown = -1,
Started = 1,
Mounted = 2,
Open = 3,
[EnumMember(Value = "OPEN MIGRATE")]
OpenMigrate = 4
}
var value = "Active";
StatusEnum status;
if (!Enum.TryParse<StatusEnum>(value, out status))
status = StatusEnum.Unknown;
public T ConvertStringValueToEnum<T>(string valueToParse){
return Convert.ChangeType(Enum.Parse(typeof(T), valueToParse, true), typeof(T));
}
public static T GetEnum<T>(string model)
{
var newModel = GetStringForEnum(model);
if (!Enum.IsDefined(typeof(T), newModel))
{
return (T)Enum.Parse(typeof(T), "None", true);
}
return (T)Enum.Parse(typeof(T), newModel.Result, true);
}
private static Task<string> GetStringForEnum(string model)
{
return Task.Run(() =>
{
Regex rgx = new Regex("[^a-zA-Z0-9 -]");
var nonAlphanumericData = rgx.Matches(model);
if (nonAlphanumericData.Count < 1)
{
return model;
}
foreach (var item in nonAlphanumericData)
{
model = model.Replace((string)item, "");
}
return model;
});
}
<Extension()>
Public Function ToEnum(Of TEnum)(ByVal value As String, ByVal defaultValue As TEnum) As TEnum
If String.IsNullOrEmpty(value) Then
Return defaultValue
End If
Return [Enum].Parse(GetType(TEnum), value, True)
End Function
public TEnum ToEnum<TEnum>(this string value, TEnum defaultValue){
if (string.IsNullOrEmpty(value))
return defaultValue;
return Enum.Parse(typeof(TEnum), value, true);}
using System;
using System.Runtime.Serialization;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
[JsonConverter(typeof(StringEnumConverter))]
public enum MyType
{
[EnumMember(Value = "person")]
Person,
[EnumMember(Value = "annan_deltagare")]
OtherPerson,
[EnumMember(Value = "regel")]
Rule,
}
using System;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
public static class EnumExtensions
{
public static TEnum ToEnum<TEnum>(this string value) where TEnum : Enum
{
var jsonString = $"'{value.ToLower()}'";
return JsonConvert.DeserializeObject<TEnum>(jsonString, new StringEnumConverter());
}
public static bool EqualsTo<TEnum>(this string strA, TEnum enumB) where TEnum : Enum
{
TEnum enumA;
try
{
enumA = strA.ToEnum<TEnum>();
}
catch
{
return false;
}
return enumA.Equals(enumB);
}
}
public class Program
{
static public void Main(String[] args)
{
var myString = "annan_deltagare";
var myType = myString.ToEnum<MyType>();
var isEqual = myString.EqualsTo(MyType.OtherPerson);
//Output: true
}
}
public static T ParseEnum<T>(this string s, T defaultValue, bool ignoreCase = false)
where T : struct, IComparable, IConvertible, IFormattable//If C# >=7.3: struct, System.Enum
{
if ((s?.Length ?? 0) == 0)
{
return defaultValue;
}
var valid = Enum.TryParse<T>(s, ignoreCase, out T res);
if (!valid || !Enum.IsDefined(typeof(T), res))
{
throw new InvalidOperationException(
$"'{s}' is not a valid value of enum '{typeof(T).FullName}'!");
}
return res;
}
public enum Store : short
{
[Description("Rio Big Store")]
Rio = 1
}
//The class also needs to be static, ok?
public static string GetDescription(this System.Enum enumValue)
{
FieldInfo fi = enumValue.GetType().GetField(enumValue.ToString());
DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(
typeof(DescriptionAttribute), false);
if (attributes != null && attributes.Length > 0) return attributes[0].Description;
else return enumValue.ToString();
}
var Desc = Store.Rio.GetDescription(); //Store is your Enum