什么是Type.GUID，它与Type.Equals（）有什么关系？ [英] What is Type.GUID and how does it relate to Type.Equals()?

问题描述

在尝试将 System.RuntimeType 的实例与泛型类型 TOut 进行比较时，我遇到了一些有趣的行为。 ：

 类型runtimeT = methodInfo.ReturnType; //使用反射获得RuntimeType 
类型genericT = typeof（TOut）; 
 
 //此条件失败，因为runtimeT不
 //似乎包含程序集限定名
 if（runtimeT.Equals（genericT））{...} 
  

以下是我的证据：

免责声明：我不确切知道CLR / type-system中的GUID是什么，当然除了首字母缩写代表全局唯一标识符。也许这个名字误导了我。

假设：我在这里假设类型 GUID唯一标识完全限定类型，包括 <$ （ null ）中缺少 factoryInfo.ReturnType 的c $ c> AssemblyQualifiedName c $ c> value。）

我的假设是错误的吗？

• 是：类型GUID真正代表什么，以及它如何使用？

library / 3ahwab82.aspxrel =nofollow noreferrer> Equals（） 是通过比较GUID来实现的吗？

解决方案

原因之一是 Type.GUID Equals 的比较是它是用户可控的项目。例如，我可以通过执行以下操作来指定我的接口的 GUID

  [Guid（2bfd006d-94b9-43af-843f-5b32f7567086）] 
 interface IFoo {...} 
  

为了生成COM互操作接口，这是必需的。如果 Equals 依赖于类型所特有的 GUID ，那么给定的开发人员可能会给他们的系统造成严重破坏键入相同的 GUID ，例如 string ， int 等等...

I came across some interesting behavior while trying to compare an instance of System.RuntimeType with a generic type TOut:

Type runtimeT = methodInfo.ReturnType; // get RuntimeType using reflection
Type genericT = typeof(TOut);

// This condition fails because runtimeT doesn't 
// seem to include an assembly qualified name
if(runtimeT.Equals(genericT)) { ... }

Here is my evidence:

Disclaimer: I don't know precisely what a GUID is in the context of the CLR / type-system, except of course that the acronym stands for global unique identifier. Perhaps the name is misleading me.

Assumption: I'm assuming here that aType GUID uniquely identifies the fully qualified type, including theAssemblyQualifiedName that's missing from factoryInfo.ReturnType in the screenshot (the null value.)

Is my assumption wrong?

• Yes: What does type GUID truly represent, and how is it used?

• No: Why wouldn't Equals() be implemented by comparing GUID?

解决方案

One reason that Type.GUID isn't used as the comparison for Equals is that it's user controllable item. For example i can dictate the GUID of my interface by doing the following

[Guid("2bfd006d-94b9-43af-843f-5b32f7567086")]
interface IFoo { ... }

This is necessary in order to produce interfaces for COM interop. If Equals relied on the GUID being unique to a type then a given developer could wreak havoc on the system by giving their type the same GUID as say string, int, etc ...

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