获取sizeof的一个结构给出的System.Type [英] Get the sizeof a struct given the System.Type

问题描述

给出一个结构 MYSTRUCT ，我可以使用的sizeof（MYSTRUCT）在该结构的实例大小不安全code。不过，我想给出一个结构的大小键入对象的结构，即的sizeof（typeof运算（MYSTRUCT））。有 Marshal.SizeOf ，但返回的非托管的编组规模，而我希望的管理的该结构的大小

Given a struct MyStruct, I can get the size of instances of that struct using sizeof(MyStruct) in unsafe code. However, I want to get the size of a struct given the Type object for the struct, ie, sizeof(typeof(MyStruct)). There is Marshal.SizeOf, but that returns the unmanaged marshalled size, whereas I want the managed size of that struct.

推荐答案

有没有记录的方式来发现有管理的结构布局。 JIT编译器利用了这个很容易的优势，这将重新排序结构的领域，以获得最佳的包装。封送处理是的总是的获得predictable布局，所指示的 [StructLayout] 属性要求。你必须跳通过 Marshal.StructureToPtr（）箍。无论你做你自己或让PInvoke的编组为您代劳。

There is no documented way to discover the layout of a managed struct. The JIT compiler takes readily advantage of this, it will reorder fields of the struct to get the best packing. Marshaling is always required to get a predictable layout, as directed by the [StructLayout] attribute. You have to jump through the Marshal.StructureToPtr() hoop. Whether you do it yourself or let the pinvoke marshaller do it for you.

Marshal.SizeOf（类型）给你的尺寸的封结构。更多的背景，为什么是这样工作是在<一个可用href="http://stackoverflow.com/questions/3361986/how-to-check-the-number-of-bytes-consumed-by-my-structure/3362736#3362736">this回答。

Marshal.SizeOf(Type) gives you the size of the marshaled struct. More background on why it works this way is available in this answer.

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