Convert enum from object to long without a try block?

Follow along in my test source. What is a good way to get a value from a enum object? Must support long. I am attempting without a try/catch block.

enum ELong: long { a = 0x100000000 开发者_如何学运维};
enum ENormal { a = 25 }

        var l = (object) ELong.a;
        var n = (object)ENormal.a;
        //will cast into the correct size
        int ii = (int)n; //ok
        long ll = (long)l; //ok
        //wont cast if its too big
        ll = (long)n; //cast exception
        //or too small
        n = (int)l; //cast exception//compile error. Cannot cast
        //lets try preventing the exception with is
        if (n is int)
            ii = (int)n;//doesnt get here.
        if (n is long)
            ll = (long)n;//doesnt get here.
        if (l is int)
            ii = (int)l;//doesnt get here
        if (l is long)
            ll = (long)l;//doesnt get here
        //WHY!!!!
        //Maybe as will do the trick?
        if (n as int? != null)
            ii = (int)n;//doesnt get here.
        if (n as long? != null)
            ll = (long)n;//doesnt get here.
        if (l as int? != null)
            ii = (int)l;//doesnt get here
        if (l as long? != null)
            ll = (long)l;//doesnt get here
        //geez. What is more stange is (int) will work while (int?) will not
        int? ni = (int?)n;//cast exception
        int iii = (int)n; //works
        ll = (long)n;

long test1 = Convert.ToInt64(l); // 4294967296
long test2 = Convert.ToInt64(n); // 25

Explanation

if (n is int)
        ii = (int)n;//doesnt get here.
    if (n is long)
        ll = (long)n;//doesnt get here.
    if (l is int)
        ii = (int)l;//doesnt get here
    if (l is long)
        ll = (long)l;//doesnt get here

n and l is neither int/long nor long?/int?, they are of type of your enum, so this is expected behavior.

Solution

Probably you should use Convert class to achieve what you want.

Example from MSDN:

static object GetAsUnderlyingType(Enum enval)
{
    Type entype = enval.GetType();

    Type undertype = Enum.GetUnderlyingType(entype);

    return Convert.ChangeType( enval, undertype );
}

1. Convert to underlying type (int or long)
2. Cast converted value to your variable (I guess simple assign result to long variable).