blocks|key|998313|text|Array+values+=+Enum.GetValues(typeof(Bar));
Random+random+=+new+Random();
Bar+randomBar+=+(Bar)values.GetValue(random.Next(values.Length));|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|998314|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>Array values = Enum.GetValues(typeof(Bar));
Random random = new Random();
Bar randomBar = (Bar)values.GetValue(random.Next(values.Length));
</code></pre>

blocks|key|998248|text|使用Enum.GetValues检索所有值的数组。然后选择一个随机数组项目。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|998249|static+Random+_R+=+new+Random+();
static+T+RandomEnumValue<T>+()
{
++++var+v+=+Enum.GetValues+(typeof+(T));
++++return+(T)+v.GetValue+(_R.Next(v.Length));
}|code-block|syntax|javascript|998250|测试：|998251|for+(int+i+=+0;+i+<+10;+i%2B%2B)+{
++++var+value+=+RandomEnumValue<System.DayOfWeek>+();
++++Console.WriteLine+(value.ToString+());
}|998252|->|998253|Tuesday
Saturday
Wednesday
Monday
Friday
Saturday
Saturday
Saturday
Friday
Wednesday|998254|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Use Enum.GetValues to retrieve an array of all values. Then select a random array item.

<pre><code>static Random _R = new Random ();
static T RandomEnumValue&lt;T&gt; ()
{
 var v = Enum.GetValues (typeof (T));
 return (T) v.GetValue (_R.Next(v.Length));
}
</code></pre>

Test:

<pre><code>for (int i = 0; i &lt; 10; i++) {
 var value = RandomEnumValue&lt;System.DayOfWeek&gt; ();
 Console.WriteLine (value.ToString ());
}
</code></pre>

->

<pre><code>Tuesday
Saturday
Wednesday
Monday
Friday
Saturday
Saturday
Saturday
Friday
Wednesday
</code></pre>

blocks|key|1212700|text|你可以这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1212701|var+rnd+=+new+Random();
return+(MyEnum)+rnd.Next(Enum.GetNames(typeof(MyEnum)).Length);|code-block|syntax|javascript|1212702|不需要存储数组|1212703|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You could just do this: 

<pre><code>var rnd = new Random();
return (MyEnum) rnd.Next(Enum.GetNames(typeof(MyEnum)).Length);
</code></pre>

No need to store arrays

blocks|key|1212550|text|调用Enum.GetValues；这将返回一个表示枚举的所有可能值的数组。从该数组中随机选取一项。将该项转换回原始枚举类型。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1212551|entityMap^0|2|E|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

Call <code>Enum.GetValues</code>; 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.

blocks|key|1212596|text|下面是它的一个通用函数。将RNG创建放在高频代码之外。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1212597|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);
++++}
}|code-block|syntax|javascript|1212598|使用示例：|1212599|System.Windows.Forms.Keys+randomKey+=+RandomEnum<System.Windows.Forms.Keys>();|1212600|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Here is a generic function for it.
Keep the RNG creation outside the high frequency code.

<pre><code>public static Random RNG = new Random();

public static T RandomEnum&lt;T&gt;()
{ 
 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);
 }
}
</code></pre>

Usage example: 

<pre><code>System.Windows.Forms.Keys randomKey = RandomEnum&lt;System.Windows.Forms.Keys&gt;();
</code></pre>

blocks|key|998445|text|改编为随机类扩展：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|998446|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));
++++}
}|code-block|syntax|javascript|998447|用法示例：|998448|var+random+=+new+Random();
var+myEnumRandom+=+random.NextEnum<MyEnum>();|998449|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Adapted as a Random class extension:

<pre class="lang-cs prettyprint-override"><code>public static class RandomExtensions
{ 
 public static T NextEnum&lt;T&gt;(this Random random)
 {
 var values = Enum.GetValues(typeof(T));
 return (T)values.GetValue(random.Next(values.Length));
 }
}
</code></pre>

Example of usage:

<pre class="lang-cs prettyprint-override"><code>var random = new Random();
var myEnumRandom = random.NextEnum&lt;MyEnum&gt;();
</code></pre>

blocks|key|1212670|text|就我个人而言，我是扩展方法的粉丝，所以我会使用这样的方法(虽然不是真正的扩展，但它看起来很相似)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1212671|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;+%2B%2Bi)+{
++++++++++++option+=+RandomEnum.Of<Options>();
++++++++++++Console.WriteLine(option);
++++++++}
++++}

}|code-block|syntax|javascript|1212672|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Personally, I'm a fan of extension methods, so I would use something like this (while not really an extension, it looks similar):

<pre><code>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&lt;T&gt;() {
 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 &lt; 10; ++i) {
 option = RandomEnum.Of&lt;Options&gt;();
 Console.WriteLine(option);
 }
 }

}
</code></pre>

blocks|key|998474|text|这些答案中的许多都是相当古老的-如果我错了请纠正我-似乎使用了一些粗略的概念，如类型擦除和动态类型转换。然而，正如用户Yarek+T指出的那样，generic+overload+of+Enum.GetValues不需要这样做|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|998475|static+Random+random+=+new+Random();

//+Somewhat+unintuitively,+we+need+to+constrain+the+type+parameter+to
//+both+struct+*and*+Enum+-+struct+is+required+b/c+the+type+can't+be
//+nullable,+and+Enum+is+required+b/c+GetValues+expects+an+Enum+type.
//+You'd+think+that+Enum+itself+would+satisfy+the+non-nullable
//+constraint,+but+alas,+me+compiler+tells+me+otherwise+-+perhaps
//+someone+more+knowledgeable+can+explain+why+this+is+in+a+comment?
static+TEnum+RandomEnumValue<TEnum>()+where+TEnum+:+struct,+Enum
{
++++TEnum[]+vals+=+Enum.GetValues<TEnum>();
++++return+vals[random.Next(vals.Length)];
}|code-block|syntax|javascript|998476|或者，就像在borja+garcia's+answer中一样，我们甚至可以将其编写为随机类的扩展|998477|public+static+class+RandomExtensions
{+++
++++public+static+TEnum+NextEnumValue<TEnum>(this+Random+random)
++++++++where+TEnum+:+struct,+Enum
++++{
++++++++TEnum[]+vals+=+Enum.GetValues<TEnum>();
++++++++return+vals[random.Next(vals.Length)];
++++}
}|998478|我们可以从mafu's+answer运行相同的测试|998479|Random+random+=+new+Random();
for+(int+i+=+0;+i+<+10;+i%2B%2B)+{
++++var+day+=+random.NextEnumValue<System.DayOfWeek>();
++++Console.WriteLine(day.ToString());
}|998480|潜在输出：|998481|Thursday
Saturday
Sunday
Sunday
Sunday
Saturday
Wednesday
Monday
Wednesday
Thursday|998482|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.microsoft.com/en-us/dotnet/api/system.enum.getvalues?view=net-6.0#system-enum-getvalues-1|1|https://stackoverflow.com/a/60847339/4661269|2|https://stackoverflow.com/a/3132139/4661269^0|2K|E|20|Y|0|0|0|6|L|1|0|0|5|D|2|0|0|0|0^^$0|@$1|2|3|4|5|6|7|18|8|@$9|19|A|1A|B|C]]|D|@$9|1B|A|1C|1|1D]]|E|$]]|$1|F|3|G|5|H|7|1E|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1F|8|@]|D|@$9|1G|A|1H|1|1I]]|E|$]]|$1|M|3|N|5|H|7|1J|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1K|8|@]|D|@$9|1L|A|1M|1|1N]]|E|$]]|$1|Q|3|R|5|H|7|1O|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|1P|8|@]|D|@]|E|$]]|$1|U|3|V|5|H|7|1Q|8|@]|D|@]|E|$I|J]]|$1|W|3|-4|5|6|7|1R|8|@]|D|@]|E|$]]]|X|$Y|$5|Z|10|11|E|$12|13]]|14|$5|Z|10|11|E|$12|15]]|16|$5|Z|10|11|E|$12|17]]]]

A lot of these answers are pretty old and - correct me if I'm wrong - seem to work with some sketchy concepts like type erasure and dynamic type casting. However, as user Yarek T points out, there's no need for that with the <a href="https://docs.microsoft.com/en-us/dotnet/api/system.enum.getvalues?view=net-6.0#system-enum-getvalues-1" rel="nofollow noreferrer">generic overload of <code>Enum.GetValues</code></a>:
<pre class="lang-cs prettyprint-override"><code>static Random random = new Random();

// Somewhat unintuitively, we need to constrain the type parameter to
// both struct *and* Enum - struct is required b/c the type can't be
// nullable, and Enum is required b/c GetValues expects an Enum type.
// You'd think that Enum itself would satisfy the non-nullable
// constraint, but alas, me compiler tells me otherwise - perhaps
// someone more knowledgeable can explain why this is in a comment?
static TEnum RandomEnumValue&lt;TEnum&gt;() where TEnum : struct, Enum
{
 TEnum[] vals = Enum.GetValues&lt;TEnum&gt;();
 return vals[random.Next(vals.Length)];
}
</code></pre>
Or, like in <a href="https://stackoverflow.com/a/60847339/4661269">borja garcia's answer</a>, we can even write this as an extension of the random class
<pre class="lang-cs prettyprint-override"><code>public static class RandomExtensions
{ 
 public static TEnum NextEnumValue&lt;TEnum&gt;(this Random random)
 where TEnum : struct, Enum
 {
 TEnum[] vals = Enum.GetValues&lt;TEnum&gt;();
 return vals[random.Next(vals.Length)];
 }
}
</code></pre>
And we can run the same test from <a href="https://stackoverflow.com/a/3132139/4661269">mafu's answer</a>:
<pre class="lang-cs prettyprint-override"><code>Random random = new Random();
for (int i = 0; i &lt; 10; i++) {
 var day = random.NextEnumValue&lt;System.DayOfWeek&gt;();
 Console.WriteLine(day.ToString());
}
</code></pre>
Potential output:
<pre><code>Thursday
Saturday
Sunday
Sunday
Sunday
Saturday
Wednesday
Monday
Wednesday
Thursday
</code></pre>

blocks|key|1212774|text|结合this+answer和its+comment的现代解决方案|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1212775|public+static+class+RandomExtensions
{
++++private+static+Random+Random+=+new+Random();

++++public+static+T+GetRandom<T>()+where+T+:+struct,+Enum
++++{
++++++++T[]?+v+=+Enum.GetValues<T>();
++++++++return+(T)v.GetValue(Random.Next(v.Length));
++++}
}|code-block|syntax|javascript|1212776|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/3132139/7032856|1|https://stackoverflow.com/questions/3132126/how-do-i-select-a-random-value-from-an-enumeration#comment122403399_3132139^0|2|B|0|E|B|1|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]|$A|W|B|X|1|Y]]|C|$]]|$1|D|3|E|5|F|7|Z|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|10|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]|Q|$5|L|M|N|C|$O|R]]]]

The modern answer combining <a href="https://stackoverflow.com/a/3132139/7032856">this answer</a> and <a href="https://stackoverflow.com/questions/3132126/how-do-i-select-a-random-value-from-an-enumeration#comment122403399_3132139">its comment</a>:
<pre><code>public static class RandomExtensions
{
 private static Random Random = new Random();

 public static T GetRandom&lt;T&gt;() where T : struct, Enum
 {
 T[]? v = Enum.GetValues&lt;T&gt;();
 return (T)v.GetValue(Random.Next(v.Length));
 }
}
</code></pre>

Given an arbitrary enumeration in C#, how do I select a random value?

(I did not find this very basic question on SO. I'll post my answer in a minute as reference for anyone, but please feel free to post your own answer.)

How do I select a random value from an enumeration?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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给定C#中的任意枚举，如何选择随机值？(我在上面没有找到这个非常基本的问题。我将立即发布我的答案供任何人参考，但请随时发布您自己的答案。)

问如何从枚举中选择随机值？
EN

回答 9

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问如何从枚举中选择随机值？
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