Toggle Enum Values of an Enum Variable

Introduction

This tip shows you how to toggle between enum values of an enum variable.

Background

Let's take an enum example:

enum Day
       {
           Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday
       }
       Day day = Day.Sunday;
       private void Toggle()
       {
           //Now, if you want to toggle values of the enum variable day what would you do?
           //generally if of switch statement is used like this
           if (day == Day.Sunday)
               day = Day.Monday;
           else if (day == Day.Monday)
               day = Day.Tuesday;
           else if (day == Day.Tuesday)
               day = Day.Wednesday;
           else if (day == Day.Wednesday)
               day = Day.Thursday;
           else if (day == Day.Thursday)
               day = Day.Friday;
           else if (day == Day.Friday)
               day = Day.Saturday;
           else if (day == Day.Saturday)
               day = Day.Sunday;}

This method is only feasible when enum has few members (7 in this case). There is an easy way and it can also be feasible when enum has more members than usual.

Using the Code

private void Toggle<T>(ref  T obj)
       {
           List<string> types = Enum.GetNames(obj.GetType()).ToList();
           int index = types.IndexOf(obj.ToString());
           if (index == types.Count - 1)
               index = 0;
           else
               index++;
           string nextstring = types[index];
           Type type = obj.GetType();
           object selected = Enum.Parse(obj.GetType(), nextstring);
           obj = (T)selected;
       }
       //Example
       private void ChangeEnumValue()
       {
           Toggle<Day>(ref day);
       }