properties - How to tell if an enum property has been set? C# -

i have class enum property so:

public class foo {     public color colortype {get;set;} }  public enum color {     red,     green, } 

now class can initialized so:

var foo = new foo(); 

without colortype property ever being set. now, i'm trying create method , perform actions on whether enum ever set or not, example have method

private void checkenum(foo foo) {     if(foo.colortype !=null)     {         //perform these actions     }else     {         //perform actions     } } 

however warning saying value never null , upon further research, if enum never set if default first value red in case, thinking adding value enum 'not set' , make value first one, if hasnt been set enum have value 'not set', there better way of doing this, proposed method seems messy

you can use 1 of 2 methods: default enum value or nullable enum.

default enum value

since enum backed integer, , int defaults zero, enum initialize default value equivalent zero. unless explicitly assign enum values, first value zero, second one, , on.

public enum color {   undefined,   red,   green }  // ...  assert.istrue(color.undefined == 0);  // success! 

nullable enum

the other way handle unassigned enum use nullable field.

public class foo {    public color? color { get; set; } }  // ...  var foo = new foo(); assert.isnull(foo.color);     // success!