将枚举值与本地化字符串资源相链接

Question

Related: Get enum from enum attribute

I want the most maintainable way of binding an enumeration and it's associated localized string values to something.

If I stick the enum and the class in the same file I feel somewhat safe but I have to assume there is a better way. I've also considered having the enum name be the same as the resource string name, but I'm afraid I can't always be here to enforce that.

using CR = AcmeCorp.Properties.Resources;

public enum SourceFilterOption
{
    LastNumberOccurences,
    LastNumberWeeks,
    DateRange
    // if you add to this you must update FilterOptions.GetString
}

public class FilterOptions
{
    public Dictionary<SourceFilterOption, String> GetEnumWithResourceString()
    {
        var dict = new Dictionary<SourceFilterOption, String>();
        foreach (SourceFilterOption filter in Enum.GetValues(typeof(SourceFilterOption)))
        {
            dict.Add(filter, GetString(filter));
        }
        return dict;
    }

    public String GetString(SourceFilterOption option)
    {
        switch (option)
        {
            case SourceFilterOption.LastNumberOccurences:
                return CR.LAST_NUMBER_OF_OCCURANCES;
            case SourceFilterOption.LastNumberWeeks:
                return CR.LAST_NUMBER_OF_WEEKS;
            case SourceFilterOption.DateRange:
            default:
                return CR.DATE_RANGE;
        }
    }
}

Answer 1

You can add DescriptionAttribute to each enum value.

public enum SourceFilterOption
{
    [Description("LAST_NUMBER_OF_OCCURANCES")]
    LastNumberOccurences,
    ...
}

Pull out the description (resource key) when you need it.

FieldInfo fi = value.GetType().GetField(value.ToString());
DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute),     
if (attributes.Length > 0)
{
    return attributes[0].Description;
}
else
{
    return value.ToString();
}

http://geekswithblogs.net/paulwhitblog/archive/2008/03/31/use-the-descriptionattribute-with-an-enum-to-display-status-messages.aspx

Edit: Response to comments (@Tergiver). Using the (existing) DescriptionAttribute in my example is to get the job done quickly. You would be better implementing your own custom attribute instead of using one outside of its purpose. Something like this:

[AttributeUsage(AttributeTargets.Field, AllowMultiple = false, Inheritable = false)]
public class EnumResourceKeyAttribute : Attribute
{
 public string ResourceKey { get; set; }
}

Answer 2

You could just crash immediately if someone doesn't update it correctly.

public String GetString(SourceFilterOption option)
{
    switch (option)
    {
        case SourceFilterOption.LastNumberOccurences:
            return CR.LAST_NUMBER_OF_OCCURANCES;
        case SourceFilterOption.LastNumberWeeks:
            return CR.LAST_NUMBER_OF_WEEKS;
        case SourceFilterOption.DateRange:
            return CR.DATE_RANGE;
        default:
            throw new Exception("SourceFilterOption " + option + " was not found");
    }
}

Answer 3

I do mapping to resourse in the following way: 1. Define a class StringDescription with ctor getting 2 parameters (type of resourse and it's name)

[AttributeUsage(AttributeTargets.Field, AllowMultiple = false)]
class StringDescriptionAttribute : Attribute
{
    private string _name;
    public StringDescriptionAttribute(string name)
    {
        _name = name;
    }

    public StringDescriptionAttribute(Type resourseType, string name)
    {
            _name = new ResourceManager(resourseType).GetString(name);

    }
    public string Name { get { return _name; } }
}

2. Create a resourse file for either culture (for example WebTexts.resx and Webtexts.ru.resx). Let is be colours Red, Green, etc...

3. Define enum:

   enum Colour{ [StringDescription(typeof(WebTexts),"Red")] Red=1 , [StringDescription(typeof(WebTexts), "Green")] Green = 2, [StringDescription(typeof(WebTexts), "Blue")] Blue = 3, [StringDescription("Antracit with mad dark circles")] AntracitWithMadDarkCircles

   }

4. Define a static method getting resource description via reflection

   public static string GetStringDescription(Enum en) {

     var enumValueName = Enum.GetName(en.GetType(),en); FieldInfo fi = en.GetType().GetField(enumValueName); var attr = (StringDescriptionAttribute)fi.GetCustomAttribute(typeof(StringDescriptionAttribute)); return attr != null ? attr.Name : ""; } 

5. Eat :

   Colour col; col = Colour.Red; Thread.CurrentThread.CurrentUICulture = new System.Globalization.CultureInfo("en-US");

     var ListOfColors = typeof(Colour).GetEnumValues().Cast<Colour>().Select(p => new { Id = p, Decr = GetStringDescription(p) }).ToList(); foreach (var listentry in ListOfColors) Debug.WriteLine(listentry.Id + " " + listentry.Decr); 

Answer 4

There is the simplest way to getting the enum description value according to culture from resources files

My Enum

  public enum DiagnosisType
    {
        [Description("Nothing")]
        NOTHING = 0,
        [Description("Advice")]
        ADVICE = 1,
        [Description("Prescription")]
        PRESCRIPTION = 2,
        [Description("Referral")]
        REFERRAL = 3

}

i have made resource file and key Same as Enum Description Value

Resoucefile and Enum Key and Value Image, Click to view resouce file image

   public static string GetEnumDisplayNameValue(Enum enumvalue)
    {
        var name = enumvalue.ToString();
        var culture = Thread.CurrentThread.CurrentUICulture;
        var converted = YourProjectNamespace.Resources.Resource.ResourceManager.GetString(name, culture);
        return converted;
    }

Call this method on view

  <label class="custom-control-label" for="othercare">YourNameSpace.Yourextenstionclassname.GetEnumDisplayNameValue(EnumHelperClass.DiagnosisType.NOTHING )</label>

It will return the string accordig to your culture

Answer 5

I've to use it in WPF here is how I achieve it

First of all you need to define an attribute

public class LocalizedDescriptionAttribute : DescriptionAttribute
{
    private readonly string _resourceKey;
    private readonly ResourceManager _resource;
    public LocalizedDescriptionAttribute(string resourceKey, Type resourceType)
    {
        _resource = new ResourceManager(resourceType);
        _resourceKey = resourceKey;
    }

    public override string Description
    {
        get
        {
            string displayName = _resource.GetString(_resourceKey);

            return string.IsNullOrEmpty(displayName)
                ? string.Format("[[{0}]]", _resourceKey)
                : displayName;
        }
    }
}

You can use that attribute like this

public enum OrderType
{
    [LocalizedDescription("DineIn", typeof(Properties.Resources))]
    DineIn = 1,
    [LocalizedDescription("Takeaway", typeof(Properties.Resources))]
    Takeaway = 2
}

Then Define a converter like

public class EnumToDescriptionConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo language)
    {
        var enumValue = value as Enum;

        return enumValue == null ? DependencyProperty.UnsetValue : enumValue.GetDescriptionFromEnumValue();
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo language)
    {
        return value;
    }
}

Then in your XAML

<cr:EnumToDescriptionConverter x:Key="EnumToDescriptionConverter" />

<TextBlock Text="{Binding Converter={StaticResource EnumToDescriptionConverter}}"/>