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EnumDropDownList and EnumHelpers
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using System; | |
using System.Collections.Generic; | |
using System.ComponentModel; | |
using System.Linq; | |
using System.Reflection; | |
using System.Web; | |
using System.Web.Mvc; | |
using System.Web.Mvc.Html; | |
namespace Geocine.Helpers | |
{ | |
public static class EnumHelpers | |
{ | |
public static HtmlString EnumDropDownList<TModel>(this HtmlHelper<TModel> helper, Type type, | |
string name, string optionLabel, object htmlAttributes) | |
{ | |
if (!type.IsEnum) throw new ArgumentException("type must be that of an enum", "type"); | |
var dictionary = new Dictionary<string, string>(); | |
var values = type.GetEnumValues(); | |
foreach (var val in values) | |
{ | |
dictionary.Add( | |
//Convert.ToInt32(val).ToString(), | |
val.ToString(), | |
type.GetDescriptionForEnum(val) | |
); | |
} | |
return helper.DropDownList(name, dictionary.ToSelectList(string.Empty), optionLabel, htmlAttributes); | |
} | |
public static SelectList ToSelectList(this IDictionary<string, string> dictionary, object selectedValue) | |
{ | |
return new SelectList(dictionary, "Key", "Value", selectedValue); | |
} | |
/// <summary> | |
/// Gets the DescriptionAttribute valud of an enum value, if none are found uses the string version of the specified value | |
/// </summary> | |
public static string GetDescription(this Enum value) | |
{ | |
Type type = value.GetType(); | |
return GetEnumDescription(value.ToString(), type); | |
} | |
public static string GetDescriptionForEnum(this Type type, object value) | |
{ | |
return GetEnumDescription(value.ToString(), type); | |
} | |
private static string GetEnumDescription(string value, Type type) | |
{ | |
MemberInfo[] memberInfo = type.GetMember(value); | |
if (memberInfo != null && memberInfo.Length > 0) | |
{ | |
// default to the first member info, it's for the specific enum value | |
var info = memberInfo.First().GetCustomAttributes(typeof(DescriptionAttribute), false).FirstOrDefault(); | |
if (info != null) | |
return ((DescriptionAttribute)info).Description; | |
} | |
// no description - return the string value of the enum | |
return value; | |
} | |
public static T GetValueFromDescription<T>(string description) | |
{ | |
var type = typeof(T); | |
if (!type.IsEnum) throw new InvalidOperationException(); | |
foreach (var field in type.GetFields()) | |
{ | |
var attribute = Attribute.GetCustomAttribute(field, | |
typeof(DescriptionAttribute)) as DescriptionAttribute; | |
if (attribute != null) | |
{ | |
if (attribute.Description == description) | |
return (T)field.GetValue(null); | |
} | |
else | |
{ | |
if (field.Name == description) | |
return (T)field.GetValue(null); | |
} | |
} | |
throw new ArgumentException("Not found.", "description"); | |
// or return default(T); | |
} | |
} | |
} |
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