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vrajs5
vrajs5

Reputation: 4126

How to identify given int value belongs to which enum

Hi before going to direct problem let me show my code :

//Definition of enum
public enum LogType
{
    Warning = -2,
    Error = -1,
    Info = 0,
    EruCtorDtor = 1,
    Notifications = 2,
    CommunicationWithAOT = 4,
    ExecutedOrder = 8,
    ERUInfo = 16,
    DebugLog = 32,
}

//Use of enum
CurrentLogFlagSettings = nLogFlag;
LogFlagMap = new SortedDictionary<LogType, int>();

ulong mask = 1;
while(mask <= nLogFlag)
{
     if ((nLogFlag & mask) == mask)
     {
          LogType type = (LogType)mask;  //Step 1
          string val = type.ToString(); //Step 2
          //Processing the value
          LogFlagMap.Add(type, tempVal)
          LogMsg(val + " added", type);
      }
      mask <<= 1;
 }

What I want is : Process step2 only after step1 has produced valid value. I mean value should be between range defined in enum definition. Otherwise I dont want to process it. for e.g.

  1. case 1 - Lets say mask value is 32, its defined in enum. So type is getting value DebugLog and so it type.ToString() (i.e. "DebugLog"), this is a valid case.
  2. case 2- Lets say mask value is 128 and its not defined in enum, in this case I dont want to process anything on 128 value. But what is happening its geting value 128 in type and type.ToString() is converting it into 128. I dont want this, I want to make sure whether 128 belongs to enum values or not.

I want to prevent 2nd case to be executed. Is there any solution for my problem?

Please let me know if more details are needed.

Upvotes: 0

Views: 736

Answers (5)

TK.
TK.

Reputation: 47873

One addition to your code could be the addition of the [Flags] attribute to you enum, this then makes it clear that the enum values are for bitwise operations

e.g.

[Flags]
public enum LogType
{
    Warning = -2,
    Error = -1,
    Info = 0,
    EruCtorDtor = 1,
    Notifications = 2,
    CommunicationWithAOT = 4,
    ExecutedOrder = 8,
    ERUInfo = 16,
    DebugLog = 32,
}

although to do this, you would need to change the values such that the Warning and Error take the top 2 bits of the enum value (assuming this is still necessary).

The c# Enum class also has the method GetName(). This might provide a nice and easy manner to retrieve the name of the value set

e.g.

Enum.GetName( typeof(LogType), 4 ); // result = CommunicationWithAOT

Upvotes: 1

Can Gencer
Can Gencer

Reputation: 8885

You can also use Enum.GetValues(typeof(LogType)) to get all the possible values for your enum and do what you want through that.

i.e.

var values = Enum.GetValues(typeof (LogType));
foreach (LogType type in values)
{
    if (((int)type & nLogMask) == (int)type)
    {
        //value is valid, process the value
    }
}

Upvotes: 1

BugFinder
BugFinder

Reputation: 17858

Firstly, let me seriously apologise, Ive had like no sleep, so if I missed the point a little. Please, just ignore me.

You can enumerate your LogType with Enum.GetValues(typeof(LogType))), so you could step through and check a value against it. I had some code, but, I couldnt promise it compiled.

Bool isValid(int i)
{
  foreach (LogType l in Enum.GetValues(typeof(LogType)))
  {
    if ((int)l == i) return true;
  }
  return false;
}

Upvotes: 3

Jon Skeet
Jon Skeet

Reputation: 1500525

I have a library called Unconstrained Melody which allows you to express all of this in a type-safe generic way and avoids boxing too. Personally I prefer that over using Enum.IsDefined, but obviously that doesn't involve learning an extra library.

It's probably not worth using Unconstrained Melody if this is the only thing you need to do with your enum, but if you've got other similar operations, you may wish to consider it.

Upvotes: 0

alex
alex

Reputation: 3720

You could use Enum.IsDefined, like so:

int value = 128;
Console.WriteLine(Enum.IsDefined(typeof(LogType), value)); // will print out False

Upvotes: 4

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