using System;

using System.Xml.Serialization;

public class Program {

    public static void Main() {

        var x = TNFeInfNFeDetImpostoICMSICMS00CST.item00;

        Console.WriteLine(x.GetAttributeDescription());

    }

}

​

public static class EnumExt {

    public static string GetAttributeDescription(this Enum enumValue) {

        var attributes = enumValue.GetType().GetMember(enumValue.ToString())[0].GetCustomAttributes(typeof(XmlEnumAttribute), false);

        return (attributes.Length > 0) ? ((XmlEnumAttribute)attributes[0]).Name : String.Empty;

    }

}

​

public enum TNFeInfNFeDetImpostoICMSICMS00CST {

    [XmlEnumAttribute("00")]

    item00 = 00,

}