C#

The Flags attribute denotes a special kind of enumeration called a bit field. The runtime 
itself does not distinguish between traditional enumerations and bit fields, but your language 
might do so. When this distinction is made, bitwise operators can be used on bit fields, but 
not on enumerations, to generate unnamed values. Enumerations are generally used for lists of 
unique elements, such as days of the week, country or region names, and so on. Bit fields are 
generally used for lists of qualities or quantities that might occur in combination, such as 
Red And Big And Fast.

Type t = typeof(MyTest);
int first = (int)MyTest.test2;
int tt1 = (int)Enum.Parse(t, "test2");
MyTest first2 = (MyTest)(first & tt1);
Console.WriteLine(first2);

<br />
        public bool IsBitExist(object evar, object val)<br />
        {<br />
<br />
<br />
            Type enumType = evar.GetType();<br />
<br />
            if (t.IsEnum)<br />
            {<br />
                if (IsFlagType(t.GetCustomAttributes(true)))<br />
                {<br />
                    byte mainEnum = (byte)evar; // convert it to a manageble data type<br />
<br />
                    object parsedString = Enum.Parse(enumType, val as string); // parse the string out to get an enum value<br />
                    object resultedEnum = mainEnum & (byte)parsedString; // lets perform the dreaded bit operator<br />
                    int passedInValue = (byte)parsedString; // This is the value from the val passed in<br />
                    int checkValue = (int)resultedEnum; // This is the value we are checking for<br />
                    return (passedInValue == checkValue ? true : false); <br />
                }<br />
                <br />
            }<br />
            return true;<br />
        }<br />

using System;

namespace EnumTests {
    [Flags]
    public enum Roles {
        Guest = 1,
        AccountManager = 2,
        Admin = 4
    }

    public class Person {
        public Roles Roles;
    }

    public class EnumTest {
        static void Main(string[] args) {
            Person p = new Person();
            p.Roles = Roles.Guest | Roles.AccountManager;
            if ((Roles.Admin & p.Roles) == 0) {
                Console.WriteLine("Person p is not an admin.  {0}", (int)(Roles.Admin & p.Roles));
            } else {
                Console.WriteLine("Person p is an admin.  {0}", (int)(Roles.Admin & p.Roles));
            }
            Console.ReadLine();
        }
    }
}