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c#reflectionenums
Piotr P
Piotr P

Reputation: 97

XmlEnumAttribute to Enum parse

I have enum class that looks like this:

public enum StupidEnum
    {

        /// <remarks/>
        [System.Xml.Serialization.XmlEnumAttribute("01")]
        Item01,

        /// <remarks/>
        [System.Xml.Serialization.XmlEnumAttribute("01_1")]
        Item01_1,

        /// <remarks/>
        [System.Xml.Serialization.XmlEnumAttribute("01_11")]
        Item01_11,
}

And now I would like to get Item01_11 enum object by only giving 01_11 value. In other words I have value from Xml Enum Attribute and as a result I would need enum object to be returned.

Upvotes: 0

Views: 2085

Answers (2)

gpanagopoulos
gpanagopoulos

Reputation: 2930

You can create a Utility class and method like below:

public static class EnumUtilities
{
    public static T GetValueFromXmlEnumAttribute<T>(string value) where T : Enum
    {
        foreach (var field in typeof(T).GetFields())
        {
            if (Attribute.GetCustomAttribute(field,
            typeof(XmlEnumAttribute)) is XmlEnumAttribute attribute)
            {
                if (attribute.Name == value)
                    return (T)field.GetValue(null);
            }
            else
            {
                if (field.Name == value)
                    return (T)field.GetValue(null);
            }
        }

        throw new ArgumentException("Could not parse XmlEnumAttribute. Not found.", nameof(value));
    }

And call it like:

var result = EnumUtilities.GetValueFromXmlEnumAttribute<StupidEnum>("01");

Upvotes: 0

Fabulous
Fabulous

Reputation: 2423

I have managed to get it working but it's not a very elegant solution. Since your attributes are dependent on XML serialization you'll need to read it that way. I'll post the working code, and the way I would recommend.

var testString = "01_1";
var xml = new XmlSerializer(typeof(StupidEnum));
// XmlSerializer expects XML so wrap what you got in xml tags.
using(var ms = new MemoryStream(Encoding.ASCII.GetBytes($"<StupidEnum>{testString}</StupidEnum>")))
    var item = (StupidEnum)xml.Deserialize(ms);
    Console.WriteLine(item);
}

Alternatively, you can cast the enum to an integral type and store that number then cast back to your enum when reading or use the enumerations own ability to parse a string and not rely on the xml serialization values as follows:

var testString = "Item01_1";  
// you can also just get the 01_1 and concatenate it to "Item" when parsing in the next line
var value = Enum.Parse(typeof(StupidEnum), testString);
Console.WriteLine(value);

Upvotes: 1

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