Controlling Enum .ToString()

This is a neat trick I found yesterday. I wonder why I never thought of it myself. In the .net framework there is no way how to control .ToString() for enumerations. To work around that an extension method can be created as well as an attribute to decorate the different values of the enumeration. Then we can write something like this:

public enum TestEnum
{
    [EnumString("Value One")]
    Value1,

    [EnumString("Value Two")]
    Value2,

    [EnumString("Value Three")]
    Value3
}

EnumTest test = EnumTest.Value1;
Console.Write(test.ToStringEx());

The code to accomplish this is pretty simple:

[AttributeUsage(AttributeTargets.Field)]
public class EnumStringAttribute : Attribute
{
    private string enumString;

    public EnumStringAttribute(string EnumString)
    {
        enumString = EnumString;
    }

    public override string ToString()
    {
        return enumString;
    }
}

public static class ExtensionMethods
{
    public static string ToStringEx(this Enum enumeration)
    {
        Type type = enumeration.GetType();
        FieldInfo field = type.GetField(enumeration.ToString());
        var enumString =
            (from attribute in field.GetCustomAttributes(true)
             where attribute is EnumStringAttribute
             select attribute).FirstOrDefault();

        if (enumString != null)
            return enumString.ToString();

        // otherwise...
        return enumeration.ToString();
    }
}

[TestMethod()]
public void ToStringTest()
{
    Assert.AreEqual("Value One", TestEnum.Value1.ToStringEx());
    Assert.AreEqual("Value Two", TestEnum.Value2.ToStringEx());
    Assert.AreEqual("Value Three", TestEnum.Value3.ToStringEx());
}

The credit goes to this post.

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