C#类型比较:Type.Equals vs operator ==

Question

Resharper建议改变以下内容:

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

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

至:

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

operator ==

// 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(类型o)

// 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 );

问题
为什么在比较类型时会operator ==被推荐Equals( Type o )？

Answer 1

我建议你读一个优秀的类型不是什么类型？Brad Wilson的博客文章.总结一下:由CLR管理的运行时类型(由内部类型RuntimeType表示)并不总是与a相同Type,可以对其进行扩展.Equals将检查基础系统类型,而==将检查类型本身.

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