PropertyInfo.GetValue returns the name of the enumeration constant instead of the value

Question

I am creating a serialization component that uses reflection to build serialized data, but I get weird results from the listed properties:

enum eDayFlags { Sunday = 1, Monday = 2, Tuesday = 4, Wednesday = 8, Thursday = 16, Friday = 32, Saturday = 64 } public eDayFlags DayFlags { get; set; } 

Now for the real test

 Obj Test = new Obj(); Test.DayFlags = eDayFlags.Friday; 

Serialization Result:

DayFlags = Friday

But if I set two flags in my variable:

 Obj Test = new Obj(); Test.DayFlags = eDayFlags.Friday; Test.DayFlags |= eDayFlags.Monday; 

Serialization Result:

Dayflags = 34

What I'm doing in the serialization component is pretty simple:

 //Loop each property of the object foreach (var prop in obj.GetType().GetProperties()) { //Get the value of the property var x = prop.GetValue(obj, null).ToString(); //Append it to the dictionnary encoded if (x == null) { Properties.Add(HttpUtility.UrlEncode(prop.Name) + "=null"); } else { Properties.Add(HttpUtility.UrlEncode(prop.Name) + "=" + HttpUtility.UrlEncode(x.ToString())); } } 

Can someone tell me how to get the real value of a variable from PropertyInfo.GetValue, even if this enumeration is only one value?

thanks

Answer 1

You get real value - it's just converting to a string that does not do what you expect. The value returned by prop.GetValue will have the eDayFlags value in the box.

Do you want a numeric value from an enumeration? Drop it to int . You are allowed to unpack the enumeration value into its base type.

Note that your enumeration, which should probably be called Days , should have [Flags] attached to it, given that it is an enumeration of flags.

Answer 2

This is the expected behavior.

You have not set the Flags attribute in your enum, so .ToString() returns a string representation of the enumeration listed as its base type ( int by default).

Adding [Flags] will force your .ToString() to return your expected value, i.e. "Monday, Friday"

---

If you decompile the Enum class, you will see code that looks like this in the implementation of ToString() :

 //// If [Flags] is NOT present if (!eT.IsDefined(typeof (FlagsAttribute), false)) //// Then returns the name associated with the value, OR the string rep. of the value //// if the value has no associated name (which is your actual case) return Enum.GetName((Type) eT, value) ?? value.ToString(); else //// [Flags] defined, so return the list of set flags with //// a ", " between return Enum.InternalFlagsFormat(eT, value);