Calculating Enum Values that aren't powers of two using the current enumeration values

Question

// SortedSet is not necessary but it has convenient Min and Max properties.
SortedSet<MyEnum> enumValues = new SortedSet<MyEnum>();
foreach (MyEnum e in Enum.GetValues(typeof(MyEnum)))
enumValues.Add(e);
// enumValues.Max * 2 to check all combinations including the last flag.
for (int i = (int)enumValues.Min + 1; i < (int)enumValues.Max * 2; i++)
MyEnum currentlyChecked = (MyEnum)i;
// if there's no equivalent of i defined in MyEnum
if (!enumValues.Contains(currentlyChecked))
string representation = "";
// Iterate over all MyEnum flags which underlying value is lower than i
// and add those flags which are contained in (MyEnum)i to the string representation
// of the value missing from the MyEnum enumeration.
foreach (MyEnum lowerValue in enumValues.Where(e => (int)e < i))
if (currentlyChecked.HasFlag(lowerValue))
representation += lowerValue.ToString();
if (String.IsNullOrEmpty(representation))
representation = "[MISSING FLAG]";
if (representation.Contains("None") | representation.Contains("Undefined"))
representation = representation.Replace("Undefined", "");
representation = representation.Replace("None", "");
Console.WriteLine("Missing value: {0} - {1}", i, representation);
I have the above code, which works great when The type of the Enumeration is known. However, the actual code is loading the Enumerations through reflection and placing the values and names into a Dictionary <int, string>. I need to be able to use the
above code with my dictionary to achieve the same result, however  when I try to modify the above code for the dictionary, I run into a problem.
The Enum that it is scanning looks like this:
[Flags]
public enum Method
Undefined = 0,
Site = 1,
Manual = 2,
API = 4
and the output should be
3: SiteManual - This works fine
5: PortalAPI
6: ManualAPI
7: SiteManualAPI
However, the output it is giving me is
3: SiteManual
5: SiteManualAPI
6: SiteManualAPI
7: SiteManualAPI
How do I adapt the above code so I can calculate the proper values without having Enum type, since I can't seem to create the sorted set from the reflection type.

Answer 1

I guess you want something like this:
int someValue = 5;
string result = ((int[])Enum.GetValues(typeof(Method)))
.Aggregate("", (a, s) =>
if ((someValue & s) != 0)
a += Enum.GetName(typeof(Method), s) + " ";
return a;
// someValue=5 -> Site API
// someValue=6 -> Manual API
// someValue=7 -> Site Manual API
// someValue=13 -> Site API