.Net Tips – converting between Enum and string

If you’re reading this then you should already know what an enum is in C# and that the underlying type of an enum element is int and you can convert between int and enum using casting:

public enum MyColours { Red, Green, Blue}
MyColours red = MyColours.Red;
int redInt = (int) red; // this return 0, the default value for the first element in an enum
MyColours redFromInt = (MyColours) redInt; // this returns MyColours.Red

However, sometimes you want to convert an enum element to and from strings instead of ints because:

  1. they’re more humanly readable
  2. changing the order of the elements won’t break your application

If you have used an enum value as part of a string.Format call like this:

string.Format("Is your favourite colour [{0}]?", MyColours.Green);

Then you’ll see that the string literal “Green” is displayed rather than the underlying integer, because the default ToString method has taken care of the enum to string conversion for you already. There is also an overload of the ToString method which takes a format string to allow you to return the integer value, string name, or hexdecimal representation, see the examples here.

To convert from a string name of a enum element back to its enum form you’ll need the help of the Enum class:

string redString = MyColours.Red.ToString(); // this returns "Red"
MyColours red = (MyColours)Enum.Parse(typeof(MyColours), redString); // this returns MyColours.Red

There are some other useful methods on the Enum class such as IsDefined too, see the list of available methods here.

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