Provides several methods for working with enum with C#
Created
January 29, 2024 16:05
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Enum helpers
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| public enum BookCategories | |
| { | |
| [Description("Options")] | |
| [Display(Name = "Select")] | |
| Select = 0, | |
| [Description("Space Travel")] | |
| [Display(Name = "Space Travel")] | |
| SpaceTravel = 1, | |
| [Description("Adventure")] | |
| [Display(Name = "Adventure")] | |
| Adventure = 2, | |
| [Description("Popular sports")] | |
| [Display(Name = "Popular sports")] | |
| Sports = 3, | |
| [Description("Cars")] | |
| [Display(Name = "Cars")] | |
| Automobile = 4, | |
| [Description("Programming with C#")] | |
| [Display(Name = "Programming with C# 12")] | |
| Programming = 5 | |
| } |
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| using System.ComponentModel; | |
| using System.ComponentModel.DataAnnotations; | |
| using System.Reflection; | |
| namespace TODO.Classes; | |
| public static class Enums | |
| { | |
| public static List<T> ToList<T>() | |
| { | |
| var enumType = typeof(T); | |
| if (enumType.BaseType != typeof(Enum)) | |
| { | |
| throw new ArgumentException($"T must be of type System.Enum"); | |
| } | |
| var enumArray = Enum.GetValues(enumType); | |
| List<T> list = new(enumArray.Length); | |
| list.AddRange(enumArray.Cast<int>().Select(x => (T)Enum.Parse(enumType, x.ToString()))); | |
| return list; | |
| } | |
| public static string DisplayName(this Enum sender) | |
| { | |
| return sender.GetType() | |
| .GetMember(sender.ToString()) | |
| .First() | |
| .GetCustomAttribute<DisplayAttribute>()! | |
| .GetName(); | |
| } | |
| public static List<KeyValuePair<string, Enum>> DescriptionAsDictionary<T>() => | |
| Enum.GetValues(typeof(T)).Cast<T>() | |
| .Cast<Enum>() | |
| .Select(value => new KeyValuePair<string, Enum>( | |
| (Attribute.GetCustomAttribute(value.GetType().GetField(value.ToString())!, | |
| typeof(DescriptionAttribute)) as DescriptionAttribute)!.Description, value)) | |
| .ToList(); | |
| } |
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| List<BookCategories> categories = Enums | |
| .ToList<BookCategories>(); | |
| var descriptions = categories | |
| .Select((category,index) => new {Value = category, Index = index}) | |
| .ToList(); | |
| List<KeyValuePair<string, Enum>> dictionary = Enums.DescriptionAsDictionary<BookCategories>(); | |
| Debug.WriteLine(BookCategories.Programming.DisplayName()); | |
| Debug.WriteLine(""); | |
| descriptions.ForEach(x => Debug.WriteLine($"{x.Index,-4}{x.Value}")); | |
| Debug.WriteLine(""); | |
| dictionary.ForEach(x => Debug.WriteLine($"{x.Key,-22}{x.Value}")); |
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Wouldn't it be better to use generic constraints for type-safety and not worry about the cast in the first place potentially failing from using this method on a non-Enum? I would also probably use a real generic dictionary as it would be an odd case to have two or more of the exact same description since that would defeat the point in most use cases (i.e. keys we can assume are distinct). Alternatively, a better method name than
DescriptionAsDictionarymight beDescriptionAsMappingsif the value isn't a bucket/collection of related enum values with the same description.