How can I use a special char in a C# enum?

Even if you could do that (and it looks you can't), it probably wouldn't be a good idea, because you'd be mixing how the enum should be displayed with the program code to manipulate it. A better option would be to define an attribute (or use existing DisplayNameAttribute) and annotate your enum with names as additional meta-data:

public enum Unit{ [DisplayName("Hz")] Hertz, [DisplayName("%V")] Volt } 

Just to register another way to do that, in a simple way, you can define "your own" enumerator with constants. In your example

public class UnitEnum { public const string KW = "KW"; public const string Volt = "%V"; } 

To access, it just: UnitEnum.Volt

This answer is related to the one from @Coppermill I feel using the DescriptionAttribute is more semantically correct when working with Enums

public enum ReportStatus { [Description("Reports that are running")] Running, [Description("Reports that are pending to run")] Pending, [Description("Reports that have errored while running")] Error, [Description("Report completed successfully.")] Finished } 

Then I read from it like such

 public static bool IsNullable(this Type type) { if (!type.IsGenericType) return false; var g = type.GetGenericTypeDefinition(); return (g.Equals(typeof (Nullable<>))); } public static Type ConcreteType(this Type type) { if (IsNullable(type)) type = UnderlyingTypeOf(type); return type; } 

.

 public static string ReadDescription<T>(T enumMember) { if (typeof (T).IsNullable() && enumMember == null) return null; var type = (typeof (T).ConcreteType()); var fi = type.GetField(enumMember.ToString()); var attributes = fi.GetCustomAttributes(typeof (DescriptionAttribute), false); if(attributes.Length == 0) return enumMember.ToString(); return attributes.Cast<DescriptionAttribute>().First().Description; } 

Then usage would be ReadDescription(ReportStatus.Running) I also have a method that will convert an Enum into a KeyValuePair Enumerable for binding an Enum to a DropDown.

Sorry, but I just realized that I didn't answer the question. I will not delete my answer because someone may find these code snippets helpful.

I agree completely with Tomas Petricek, so I will not repeat his answer.

Here is my solution to the problem. I been using this code for about five years. I decided to create a custom attribute in order to use the DisplayName attribute for captions and such.

Public Module MainModule Public Sub Main() Console.WriteLine(EnumEx.GetNumberFormatString(Unit.Volt), 120.13) End Sub End Module 

Public Enum Unit <NumberFormatString("{0} Hz"), DisplayName("Hertz")> Hz <NumberFormatString("{0} %V"), DisplayName("%Volt")> pV End Enum 

<AttributeUsage(AttributeTargets.All)> _ Public NotInheritable Class NumberFormatStringAttribute Inherits Attribute Public Shared ReadOnly [Default] As NumberFormatStringAttribute = New NumberFormatStringAttribute Private _format As String Public Sub New() Me.New(Char.MinValue) End Sub Public Sub New(ByVal format As String) _format = format End Sub Public Overrides Function Equals(ByVal obj As Object) As Boolean If (obj Is Me) Then Return True End If Dim oAttribute As NumberFormatStringAttribute = TryCast(obj, NumberFormatStringAttribute) If (Not oAttribute Is Nothing) Then Return (oAttribute.NumberFormatString = Me.NumberFormatString) End If Return False End Function Public Overrides Function GetHashCode() As Integer Return Me.NumberFormatString.GetHashCode End Function Public Overrides Function IsDefaultAttribute() As Boolean Return Me.Equals(NumberFormatStringAttribute.Default) End Function Public ReadOnly Property NumberFormatString() As String Get Return Me.NumberFormatStringValue End Get End Property Private Property NumberFormatStringValue() As String Get Return _format End Get Set(ByVal value As String) _format = value End Set End Property End Class 

Public NotInheritable Class EnumEx Private Sub New() End Sub Public Shared Function GetNumberFormatString(ByVal value As Object) As String Dim sResult As String = Nothing Dim oFieldInfo As System.Reflection.FieldInfo = value.GetType.GetField(value.ToString) If Not (oFieldInfo Is Nothing) Then Dim oCustomAttributes() As Object = oFieldInfo.GetCustomAttributes(GetType(NumberFormatStringAttribute), True) If (Not (oCustomAttributes Is Nothing)) AndAlso oCustomAttributes.Length > 0 Then sResult = DirectCast(oCustomAttributes(0), NumberFormatStringAttribute).NumberFormatString End If End If Return sResult End Function End Class 

Enum members shouldn't be used for user interface display purposes. But you can use simple tricks with DisplayName("Your Property Display Name") for this matter as bellow.

//Enum public enum ErrorCodes { [DisplayName("U-volt")] UVolt = 2, [DisplayName("L-trip")] Ltrip = 5 } //Here you can retrive Display name as bellow public class MyClass{ public void readEnumDisplayName(){ String ErroCode = Enum.GetName(typeof(ErrorCodes), 5); // Find Error Name using Integer value MemberInfo property = typeof(ErrorCodes).GetRuntimeField(ErroCode); //Find Field var dd = property.GetCustomAttribute(typeof(DisplayNameAttribute)) as DisplayNameAttribute; //Find Display Attribute if (dd != null) //Check if null { var name = dd.DisplayName; //Retrive Display name } } } 

Some can state that Enumerations are for Code only, I must disagree and I use to Code and Display functionality.

In your particular case I would use the full word

public enum UnitType { Kilowatt, Kilovolt, Volt, Hertz, Ohm, Faraday } 

So I can use them in a Dropdown for example as (when I need to create a new item, all I need to do is append that item into the Enumeration...

ddl.Items.Clear(); foreach (string type in Enum.GetNames(typeof(UnitType))) ddl.Items.Add(type); 

I tend to use Space Separator, but I normally use underscore to make spaces, like

public enum myType { Process_Time, Process_Order, Process_Invoices } 

and the DropDownList item would be

ddl.Items.Add(type.Replace("_", " ")); 

when I want to set the Type from the DropDown, I use the Parse

UnitType unit = (UnitType)Enum.Parse( typeof(UnitType), ddl.SelectedValue.toString()); 

off course, if you use Separator

 ddl.SelectedValue.toString().Replace(" ", "_")); 

Some rules to have in consideration to write better code

• Always write Type to an Enum, in you case Unit should be UnitType
• Use Title Case for Enumeration Objects

As a reminder

• You can use an Enum in a Bit Operation adding [Flags] keyword
• You can specify the integer value of the Enum if you don't want to have: 0, 1, 2, 3...

I hope I can help someone.