Files
Umbraco-CMS/src/Umbraco.Core/Enum.cs
2018-06-29 19:52:40 +02:00

110 lines
3.4 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
namespace Umbraco.Core
{
/// <summary>
/// Provides utility methods for handling enumerations.
/// </summary>
/// <remarks>
/// Taken from http://damieng.com/blog/2010/10/17/enums-better-syntax-improved-performance-and-tryparse-in-net-3-5
/// </remarks>
public static class Enum<T>
where T : struct
{
private static readonly List<T> Values;
private static readonly Dictionary<string, T> InsensitiveNameToValue;
private static readonly Dictionary<string, T> SensitiveNameToValue;
private static readonly Dictionary<int, T> IntToValue;
private static readonly Dictionary<T, string> ValueToName;
static Enum()
{
Values = Enum.GetValues(typeof(T)).Cast<T>().ToList();
IntToValue = new Dictionary<int, T>();
ValueToName = new Dictionary<T, string>();
SensitiveNameToValue = new Dictionary<string, T>();
InsensitiveNameToValue = new Dictionary<string, T>();
foreach (var value in Values)
{
var name = value.ToString();
IntToValue[Convert.ToInt32(value)] = value;
ValueToName[value] = name;
SensitiveNameToValue[name] = value;
InsensitiveNameToValue[name.ToLowerInvariant()] = value;
}
}
public static bool IsDefined(T value)
{
return ValueToName.Keys.Contains(value);
}
public static bool IsDefined(string value)
{
return SensitiveNameToValue.Keys.Contains(value);
}
public static bool IsDefined(int value)
{
return IntToValue.Keys.Contains(value);
}
public static IEnumerable<T> GetValues()
{
return Values;
}
public static string[] GetNames()
{
return ValueToName.Values.ToArray();
}
public static string GetName(T value)
{
return ValueToName.TryGetValue(value, out var name) ? name : null;
}
public static T Parse(string value, bool ignoreCase = false)
{
var names = ignoreCase ? InsensitiveNameToValue : SensitiveNameToValue;
if (ignoreCase) value = value.ToLowerInvariant();
if (names.TryGetValue(value, out var parsed))
return parsed;
throw new ArgumentException($"Value \"{value}\"is not a valid {typeof(T).Name} enumeration value.", nameof(value));
}
public static bool TryParse(string value, out T returnValue, bool ignoreCase = false)
{
var names = ignoreCase ? InsensitiveNameToValue : SensitiveNameToValue;
if (ignoreCase) value = value.ToLowerInvariant();
return names.TryGetValue(value, out returnValue);
}
public static T? ParseOrNull(string value)
{
if (string.IsNullOrWhiteSpace(value))
return null;
if (InsensitiveNameToValue.TryGetValue(value.ToLowerInvariant(), out var parsed))
return parsed;
return null;
}
public static T? CastOrNull(int value)
{
if (IntToValue.TryGetValue(value, out var foundValue))
return foundValue;
return null;
}
}
}