Check if enum is obsolete
The following method checks whether an enum value has the Obsolete
attribute:
public static bool IsObsolete(Enum value)
{
var fi = value.GetType().GetField(value.ToString());
var attributes = (ObsoleteAttribute[])
fi.GetCustomAttributes(typeof(ObsoleteAttribute), false);
return (attributes != null && attributes.Length > 0);
}
You can use it like this:
var isObsolete2 = IsObsolete(MyEnums.MyEnum2); // returns true
var isObsolete3 = IsObsolete(MyEnums.MyEnum3); // returns false
You can, but you'll need to use reflection:
bool hasIt = typeof (MyEnums).GetField("MyEnum2")
.GetCustomAttribute(typeof (ObsoleteAttribute)) != null;
In the other hand, you can get all obsolete enum fields using some LINQ:
IEnumerable<FieldInfo> obsoleteEnumValueFields = typeof (MyEnums)
.GetFields(BindingFlags.Public | BindingFlags.Static)
.Where(fieldInfo => fieldInfo.GetCustomAttribute(typeof (ObsoleteAttribute)) != null);
And finally, using above result, you can get all obsolete enum values!
IEnumerable<MyEnums> obsoleteEnumValues = obsoleteEnumValueFields
.Select(fieldInfo => (MyEnums)fieldInfo.GetValue(null));
Thanks @M4N here's an extension method approach of your solution:
public static bool IsObsolete(this Enum value)
{
FieldInfo fieldInfo = value.GetType().GetField(value.ToString());
ObsoleteAttribute[] attributes = (ObsoleteAttribute[])fieldInfo.GetCustomAttributes(typeof(ObsoleteAttribute), false);
return (attributes != null && attributes.Length > 0);
}
Call it like this:
bool isObsolete2 = MyEnums.MyEnum2.IsObsolete(); // true
bool isObsolete3 = MyEnums.MyEnum3.IsObsolete(); // false
Here is a very clean extension method. The trick is that you are reflecting on a field off of the enum's type using the enum's name.
public static bool IsObsolete(this Enum value)
{
var enumType = value.GetType();
var enumName = enumType.GetEnumName(value);
var fieldInfo = enumType.GetField(enumName);
return Attribute.IsDefined(fieldInfo, typeof(ObsoleteAttribute));
}