{"id":77815,"date":"2022-12-05T07:30:37","date_gmt":"2022-12-05T06:30:37","guid":{"rendered":"https:\/\/drafts.code-maze.com\/?p=77477"},"modified":"2022-12-08T20:28:45","modified_gmt":"2022-12-08T19:28:45","slug":"enumerate-enum-csharp","status":"publish","type":"post","link":"https:\/\/code-maze.com\/enumerate-enum-csharp\/","title":{"rendered":"How to Enumerate an Enum in C#"},"content":{"rendered":"

In this article, we’re going to look at some of the ways we can enumerate an Enum in C#. Enums<\/a> allow us to declare a group of related constant values in a readable way where the underlying data type is usually an integer.\u00a0<\/p>\n

To download the source code for this article, you can visit our GitHub repository<\/a>.<\/div>\n

Let’s start.<\/p>\n

Creating an Example Enum<\/h2>\n

Let’s start by creating an enumeration we can use throughout the rest of this article:<\/p>\n

internal enum DayOfWeek\r\n{\r\n    Monday,\r\n    Tuesday,\r\n    Wednesday,\r\n    Thursday,\r\n    Friday,\r\n    Saturday,\r\n    Sunday\r\n}<\/pre>\n
We’ve made an enumeration called DayOfWeek<\/code> where each value is one of the days of the week.<\/p>\n
How to Enumerate Using Enum.GetValues(Type type)<\/h2>\n
Before we enumerate our DayOfWeek<\/code> enum we need to get the values into an enumerable type. Fortunately, there’s a handy static method on the Enum<\/code> class that allows us to get the values of an enumeration into an Array<\/code> object:<\/p>\n
var daysOfWeek = Enum.GetValues(typeof(DayOfWeek));<\/code><\/p>\n
The return value of the method Enum.GetValues(Type type)<\/code> is Array<\/code>.\u00a0<\/p>\n
Now we can loop through the values in that array and do something with each value:<\/p>\n
foreach (var dayOfWeek in daysOfWeek)\r\n{\r\n    Console.WriteLine(dayOfWeek);\r\n}<\/pre>\n
The below output will be the result:<\/p>\n
Monday\r\nTuesday\r\nWednesday\r\nThursday\r\nFriday\r\nSaturday\r\nSunday<\/pre>\n
The application prints out the name of the constants. This is because the result of Enum.GetValues(Type type)<\/code> is an Array<\/code> object which holds an array of type object<\/code>. When we Console.WriteLine()<\/code> with an object<\/code> type, the ToString()<\/code> method is what’s used.<\/p>\n
To get the integer value of each enumeration value we can cast the value of dayofWeek<\/code> to an int<\/code>:<\/p>\n
Console.WriteLine((int)dayOfWeek);<\/code><\/p>\n
Alternatively, we can specify that we want dayOfWeek<\/code> to be an int<\/code> when we declare it in our loop:<\/p>\n
foreach (int dayOfWeek in daysOfWeekValues)\r\n{\r\n    Console.WriteLine(dayOfWeek);\r\n}<\/pre>\n
This will produce an output in the console:<\/p>\n
0\r\n1\r\n2\r\n3\r\n4\r\n5\r\n6<\/pre>\n
How to Enumerate Using Enum.GetValues<TEnum>()<\/h2>\n
Since .NET 5, there has been another version of the Enum.GetValues<\/code> method and this one is a generic method.<\/p>\n
Instead of calling Enum.GetValues(Type type)<\/code> and passing in the type of our enumeration using the typeof<\/code> keyword, we can pass our DayOfWeek<\/code> enumeration as a type parameter:<\/p>\n
var daysOfWeek = Enum.GetValues<DayOfWeek>();<\/code><\/p>\n
By calling Enum.GetValues this way, the return type is an IEnumerable<DayOfWeek><\/code> so we don’t need to do any casting. Our daysOfWeek<\/code> variable is now implicitly of type IEnumerable<DayOfWeek><\/code>.<\/p>\n
We can loop through this in the same way that we have before:<\/p>\n
foreach (var dayOfWeek in Enum.GetValues<DayOfWeek>())\r\n{\r\n    Console.WriteLine($\"{dayOfWeek} = {(int)dayOfWeek}\");\r\n}<\/pre>\n
And, let’s inspect the output:<\/p>\n
Monday = 0\r\nTuesday = 1\r\nWednesday = 2\r\nThursday = 3\r\nFriday = 4\r\nSaturday = 5\r\nSunday = 6<\/pre>\n
How to Enumerate an Enum Using Reflection<\/h2>\n
Using reflection in C#<\/a> should always be done with a lot of care because it can be very CPU-intensive and not something that you would typically want to do a lot of. In any case, we can use reflection to enumerate our DayOfWeek<\/code> enumeration.<\/p>\n
First, we want to get the field information for our enumeration:<\/p>\n
FieldInfo[] fields = typeof(DayOfWeek).GetFields(BindingFlags.Static | BindingFlags.Public);<\/code><\/p>\n
This will give us a FieldInfo<\/code> for each of the enumeration values. Now we’ll use LINQ to:<\/p>\n