Исходный код вики Generic enum to int
Редактировал(а) Alexandr Fokin 2024/09/10 13:02
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| author | version | line-number | content |
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1.1 | 1 | |(% style="width:103px" %) |(% style="width:1334px" %) |
| 2 | |(% style="width:103px" %) |(% style="width:1334px" %)How do I cast a generic enum to int? | ||
| 3 | [[https:~~/~~/stackoverflow.com/questions/16960555/how-do-i-cast-a-generic-enum-to-int>>url:https://stackoverflow.com/questions/16960555/how-do-i-cast-a-generic-enum-to-int]] | ||
| 4 | |(% style="width:103px" %) |(% style="width:1334px" %){{code language="c#"}}public static class EnumHelper | ||
| 5 | { | ||
| 6 | /// <summary> | ||
| 7 | /// Использует ExpressionTree для производительности (no boxing object) | ||
| 8 | /// </summary> | ||
| 9 | public static int EnumToInt<T>(this T value) | ||
| 10 | where T : struct, Enum | ||
| 11 | => EnumHelper.GenericEnum<T>.EnumToInt(value); | ||
| 12 | |||
| 13 | private static class GenericEnum<T> | ||
| 14 | where T : struct, Enum | ||
| 15 | { | ||
| 16 | public static readonly Func<T, int> EnumToInt; | ||
| 17 | |||
| 18 | static GenericEnum() | ||
| 19 | { | ||
| 20 | { | ||
| 21 | var inputParameter = Expression.Parameter(typeof(T)); | ||
| 22 | var body = Expression.Convert(inputParameter, typeof(int)); | ||
| 23 | var lambda = Expression.Lambda<Func<T, int>>(body, inputParameter); | ||
| 24 | EnumToInt = lambda.Compile(); | ||
| 25 | } | ||
| 26 | } | ||
| 27 | } | ||
| 28 | }{{/code}} | ||
| 29 | |||
| 30 |