C＃类型比较：Type.Equals VS运营商== [英] C# Type Comparison: Type.Equals vs operator ==

问题描述

ReSharper的建议下面进行从变更：

Resharper suggests that the following be changed from:

Type foo = typeof( Foo );
Type bar = typeof( Bar );

if( foo.Equals( bar ) ) { ... }

要：

if( foo == bar ) { ... }

运算符==

// Summary:
//     Indicates whether two System.Type objects are equal.
//
// Parameters:
//   left:
//     The first object to compare.
//
//   right:
//     The second object to compare.
//
// Returns:
//     true if left is equal to right; otherwise, false.
public static bool operator ==( Type left, Type right );

等于（O型）

// Summary:
//     Determines if the underlying system type of the current System.Type is the
//     same as the underlying system type of the specified System.Type.
//
// Parameters:
//   o:
//     The System.Type whose underlying system type is to be compared with the underlying
//     system type of the current System.Type.
//
// Returns:
//     true if the underlying system type of o is the same as the underlying system
//     type of the current System.Type; otherwise, false.
public virtual bool Equals( Type o );

问

为什么会运算符== 推荐过等于（O型）比较类型时？

推荐答案

我建议你阅读优秀的当是一类不是一个类型？博客文章由布拉德·威尔逊。总结：一个运行时类型（再由内部类型RuntimeType psented $ P $），由CLR管理并不总是一样的类型，它可以延长。 等于将检查底层系统类型，而 == 将检查该类型本身。

I suggest that you read the excellent when is a type not a type? blog post by Brad Wilson. To summarize: a runtime type (represented by the internal type RuntimeType), managed by the CLR is not always the same as a Type, which can be extended. Equals will check the underlying system type, whereas == will check the type itself.

一个简单的例子：

Type type = new TypeDelegator(typeof(int));
Console.WriteLine(type.Equals(typeof(int))); // Prints True
Console.WriteLine(type == typeof(int));      // Prints False

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