blocks|key|1317123|text|如果您想检查它是否是泛型类型的实例：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1317124|return+list.GetType().IsGenericType;|code-block|syntax|javascript|1317125|如果您想检查它是否是一个通用List<T>|offset|length|style|CODE|1317126|return+list.GetType().GetGenericTypeDefinition()+==+typeof(List<>);|1317127|正如Jon所指出的，这将检查确切的类型等价性。返回false并不一定意味着list+is+List<T>返回false+(即不能将对象赋给List<T>变量)。|1317128|entityMap^0|0|0|E|7|0|0|P|5|11|F|1I|5|1X|7|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|Y|8|@$I|Z|J|10|K|L]|$I|11|J|12|K|L]|$I|13|J|14|K|L]|$I|15|J|16|K|L]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|R|$]]

If you want to check if it's an instance of a generic type:

<pre><code>return list.GetType().IsGenericType;
</code></pre>

If you want to check if it's a generic <code>List&lt;T&gt;</code>:

<pre><code>return list.GetType().GetGenericTypeDefinition() == typeof(List&lt;&gt;);
</code></pre>

As Jon points out, this checks the exact type equivalence. Returning <code>false</code> doesn't necessarily mean <code>list is List&lt;T&gt;</code> returns <code>false</code> (i.e. the object cannot be assigned to a <code>List&lt;T&gt;</code> variable).

blocks|key|1317156|text|return+list.GetType().IsGenericType;|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1317157|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>return list.GetType().IsGenericType;
</code></pre>

blocks|key|1317254|text|我假设您不仅想知道类型是否是泛型，而且还想知道对象是否是特定泛型类型的实例，而不需要知道类型参数。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1317255|不幸的是，这并不是非常简单。如果泛型类型是一个类(就像本例中一样)，这并不是太糟糕，但对于接口来说就更难了。下面是一个类的代码：|1317256|using+System;
using+System.Collections.Generic;
using+System.Reflection;

class+Test
{
++++static+bool+IsInstanceOfGenericType(Type+genericType,+object+instance)
++++{
++++++++Type+type+=+instance.GetType();
++++++++while+(type+!=+null)
++++++++{
++++++++++++if+(type.IsGenericType+&&
++++++++++++++++type.GetGenericTypeDefinition()+==+genericType)
++++++++++++{
++++++++++++++++return+true;
++++++++++++}
++++++++++++type+=+type.BaseType;
++++++++}
++++++++return+false;
++++}

++++static+void+Main(string[]+args)
++++{
++++++++//+True
++++++++Console.WriteLine(IsInstanceOfGenericType(typeof(List<>),
++++++++++++++++++++++++++++++++++++++++++++++++++new+List<string>()));
++++++++//+False
++++++++Console.WriteLine(IsInstanceOfGenericType(typeof(List<>),
++++++++++++++++++++++++++++++++++++++++++++++++++new+string[0]));
++++++++//+True
++++++++Console.WriteLine(IsInstanceOfGenericType(typeof(List<>),
++++++++++++++++++++++++++++++++++++++++++++++++++new+SubList()));
++++++++//+True
++++++++Console.WriteLine(IsInstanceOfGenericType(typeof(List<>),
++++++++++++++++++++++++++++++++++++++++++++++++++new+SubList<int>()));
++++}

++++class+SubList+:+List<string>
++++{
++++}

++++class+SubList<T>+:+List<T>
++++{
++++}
}|code-block|syntax|javascript|1317257|编辑:如注释中所述，这可能适用于接口：|1317258|foreach+(var+i+in+type.GetInterfaces())
{
++++if+(i.IsGenericType+&&+i.GetGenericTypeDefinition()+==+genericType)
++++{
++++++++return+true;
++++}
}|1317259|我暗自怀疑这可能有一些尴尬的边缘案例，但我现在找不到一个失败的案例。|1317260|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

I assume that you don't just want to know if the type is generic, but if an object is an instance of a particular generic type, without knowing the type arguments.

It's not terribly simple, unfortunately. It's not too bad if the generic type is a class (as it is in this case) but it's harder for interfaces. Here's the code for a class:

<pre><code>using System;
using System.Collections.Generic;
using System.Reflection;

class Test
{
 static bool IsInstanceOfGenericType(Type genericType, object instance)
 {
 Type type = instance.GetType();
 while (type != null)
 {
 if (type.IsGenericType &amp;&amp;
 type.GetGenericTypeDefinition() == genericType)
 {
 return true;
 }
 type = type.BaseType;
 }
 return false;
 }

 static void Main(string[] args)
 {
 // True
 Console.WriteLine(IsInstanceOfGenericType(typeof(List&lt;&gt;),
 new List&lt;string&gt;()));
 // False
 Console.WriteLine(IsInstanceOfGenericType(typeof(List&lt;&gt;),
 new string[0]));
 // True
 Console.WriteLine(IsInstanceOfGenericType(typeof(List&lt;&gt;),
 new SubList()));
 // True
 Console.WriteLine(IsInstanceOfGenericType(typeof(List&lt;&gt;),
 new SubList&lt;int&gt;()));
 }

 class SubList : List&lt;string&gt;
 {
 }

 class SubList&lt;T&gt; : List&lt;T&gt;
 {
 }
}
</code></pre>

EDIT: As noted in comments, this may work for interfaces:

<pre><code>foreach (var i in type.GetInterfaces())
{
 if (i.IsGenericType &amp;&amp; i.GetGenericTypeDefinition() == genericType)
 {
 return true;
 }
}
</code></pre>

I have a sneaking suspicion there may be some awkward edge cases around this, but I can't find one it fails for right now.

blocks|key|1317307|text|你可以使用更短的动态代码，尽管这可能比纯反射慢：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1317308|public+static+class+Extension
{
++++public+static+bool+IsGenericList(this+object+o)
++++{
+++++++return+IsGeneric((dynamic)o);
++++}

++++public+static+bool+IsGeneric<T>(List<T>+o)
++++{
+++++++return+true;
++++}

++++public+static+bool+IsGeneric(+object+o)
++++{
++++++++return+false;
++++}
}



var+l+=+new+List<int>();
l.IsGenericList().Should().BeTrue();

var+o+=+new+object();
o.IsGenericList().Should().BeFalse();|code-block|syntax|javascript|1317309|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|$]]

You can use shorter code using dynamic althougth this may be slower than pure reflection:

<pre><code>public static class Extension
{
 public static bool IsGenericList(this object o)
 {
 return IsGeneric((dynamic)o);
 }

 public static bool IsGeneric&lt;T&gt;(List&lt;T&gt; o)
 {
 return true;
 }

 public static bool IsGeneric( object o)
 {
 return false;
 }
}



var l = new List&lt;int&gt;();
l.IsGenericList().Should().BeTrue();

var o = new object();
o.IsGenericList().Should().BeFalse();
</code></pre>

blocks|key|1532547|text|public+static+string+WhatIsMyType<T>()
{
++++return+typeof(T).NameWithGenerics();
}

public+static+string+NameWithGenerics(this+Type+type)
{
++++if+(type+==+null)
++++++++throw+new+ArgumentNullException(nameof(type));

++++if+(type.IsArray)
++++++++return+$"{type.GetElementType()?.Name}[]";

++++if+(!type.IsGenericType)+
++++++++return+type.Name;

++++var+name+=+type.GetGenericTypeDefinition().Name;
++++var+index+=+name.IndexOf('`');
++++var+newName+=+index+==+-1+?+name+:+name.Substring(0,+index);
++++++++
++++var+list+=+type.GetGenericArguments().Select(NameWithGenerics).ToList();
++++return+$"{newName}<{string.Join(",",+list)}>";
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1532548|现在使用以下命令进行测试：|unstyled|1532549|Console.WriteLine(WhatIsMyType<IEnumerable<string>>());
Console.WriteLine(WhatIsMyType<List<int>>());
Console.WriteLine(WhatIsMyType<IList<int>>());
Console.WriteLine(WhatIsMyType<List<ContentBlob>>());
Console.WriteLine(WhatIsMyType<int[]>());
Console.WriteLine(WhatIsMyType<ContentBlob>());
Console.WriteLine(WhatIsMyType<Dictionary<string,+Dictionary<int,+int>>>());|1532550|你就会得到|1532551|IEnumerable<String>
List<Int32>
IList<Int32>
List<ContentBlob>
Int32[]
ContentBlob
Dictionary<String,Dictionary<Int32,Int32>>|1532552|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|P|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$B|C]]|$1|I|3|J|5|F|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$B|C]]|$1|M|3|-4|5|F|7|T|8|@]|9|@]|A|$]]]|N|$]]

<pre><code>public static string WhatIsMyType&lt;T&gt;()
{
 return typeof(T).NameWithGenerics();
}

public static string NameWithGenerics(this Type type)
{
 if (type == null)
 throw new ArgumentNullException(nameof(type));

 if (type.IsArray)
 return $&quot;{type.GetElementType()?.Name}[]&quot;;

 if (!type.IsGenericType) 
 return type.Name;

 var name = type.GetGenericTypeDefinition().Name;
 var index = name.IndexOf('`');
 var newName = index == -1 ? name : name.Substring(0, index);
 
 var list = type.GetGenericArguments().Select(NameWithGenerics).ToList();
 return $&quot;{newName}&lt;{string.Join(&quot;,&quot;, list)}&gt;&quot;;
}
</code></pre>
Now test with this:
<pre><code>Console.WriteLine(WhatIsMyType&lt;IEnumerable&lt;string&gt;&gt;());
Console.WriteLine(WhatIsMyType&lt;List&lt;int&gt;&gt;());
Console.WriteLine(WhatIsMyType&lt;IList&lt;int&gt;&gt;());
Console.WriteLine(WhatIsMyType&lt;List&lt;ContentBlob&gt;&gt;());
Console.WriteLine(WhatIsMyType&lt;int[]&gt;());
Console.WriteLine(WhatIsMyType&lt;ContentBlob&gt;());
Console.WriteLine(WhatIsMyType&lt;Dictionary&lt;string, Dictionary&lt;int, int&gt;&gt;&gt;());
</code></pre>
and you will get
<pre><code>IEnumerable&lt;String&gt;
List&lt;Int32&gt;
IList&lt;Int32&gt;
List&lt;ContentBlob&gt;
Int32[]
ContentBlob
Dictionary&lt;String,Dictionary&lt;Int32,Int32&gt;&gt;
</code></pre>

I would like to perform a test if an object is of a generic type. I've tried the following without success: 

<pre><code>public bool Test()
{
 List&lt;int&gt; list = new List&lt;int&gt;();
 return list.GetType() == typeof(List&lt;&gt;);
}
</code></pre>

What am I doing wrong and how do I perform this test?

Testing if object is of generic type in C#

如果一个对象是泛型类型，我想执行一个测试。我尝试过以下几种方法，但都没有成功：public bool Test(){ List<int> list = new List<int>(); return list.GetType() == typeof(List<>);}我做错了什么?如何执行此测试？

问测试对象是否为C#中的泛型类型
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