Here is a generic function for it. Keep the RNG creation outside the high frequency code.
public static Random RNG = new Random();
public static T RandomEnum<T>()
{
Type type = typeof(T);
Array values = Enum.GetValues(type);
lock(RNG)
{
object value= values.GetValue(RNG.Next(values.Length));
return (T)Convert.ChangeType(value, type);
}
}
Usage example:
System.Windows.Forms.Keys randomKey = RandomEnum<System.Windows.Forms.Keys>();
Call Enum.GetValues
; this returns an array that represents all possible values for your enum. Pick a random item from this array. Cast that item back to the original enum type.
Adapted as a Random class extension:
public static class RandomExtensions
{
public static T NextEnum<T>(this Random random)
{
var values = Enum.GetValues(typeof(T));
return (T)values.GetValue(random.Next(values.Length));
}
}
Example of usage:
var random = new Random();
var myEnumRandom = random.NextEnum<MyEnum>();
Personally, I'm a fan of extension methods, so I would use something like this (while not really an extension, it looks similar):
public enum Options {
Zero,
One,
Two,
Three,
Four,
Five
}
public static class RandomEnum {
private static Random _Random = new Random(Environment.TickCount);
public static T Of<T>() {
if (!typeof(T).IsEnum)
throw new InvalidOperationException("Must use Enum type");
Array enumValues = Enum.GetValues(typeof(T));
return (T)enumValues.GetValue(_Random.Next(enumValues.Length));
}
}
[TestClass]
public class RandomTests {
[TestMethod]
public void TestMethod1() {
Options option;
for (int i = 0; i < 10; ++i) {
option = RandomEnum.Of<Options>();
Console.WriteLine(option);
}
}
}
You can also cast a random value:
using System;
enum Test {
Value1,
Value2,
Value3
}
class Program {
public static void Main (string[] args) {
var max = Enum.GetValues(typeof(Test)).Length;
var value = (Test)new Random().Next(0, max - 1);
Console.WriteLine(value);
}
}
But you should use a better randomizer like the one in this library of mine.
You could just do this:
var rnd = new Random();
return (MyEnum) rnd.Next(Enum.GetNames(typeof(MyEnum)).Length);
No need to store arrays
Here's an alternative version as an Extension Method
using LINQ
.
using System;
using System.Linq;
public static class EnumExtensions
{
public static Enum GetRandomEnumValue(this Type t)
{
return Enum.GetValues(t) // get values from Type provided
.OfType<Enum>() // casts to Enum
.OrderBy(e => Guid.NewGuid()) // mess with order of results
.FirstOrDefault(); // take first item in result
}
}
public static class Program
{
public enum SomeEnum
{
One = 1,
Two = 2,
Three = 3,
Four = 4
}
public static void Main()
{
for(int i=0; i < 10; i++)
{
Console.WriteLine(typeof(SomeEnum).GetRandomEnumValue());
}
}
}
Two
One
Four
Four
Four
Three
Two
Four
One
Three
Use Enum.GetValues to retrieve an array of all values. Then select a random array item.
static Random _R = new Random ();
static T RandomEnumValue<T> ()
{
var v = Enum.GetValues (typeof (T));
return (T) v.GetValue (_R.Next(v.Length));
}
Test:
for (int i = 0; i < 10; i++) {
var value = RandomEnumValue<System.DayOfWeek> ();
Console.WriteLine (value.ToString ());
}
->
Tuesday
Saturday
Wednesday
Monday
Friday
Saturday
Saturday
Saturday
Friday
Wednesday
Source: Stackoverflow.com