在 VB.NET 中使用 DLL 导入/声明以及 .NET 未使用的参数类型
我正在开发一个项目，必须将 DLL 文件导入到几年前创建的 VB 项目中。 DLL是用C++创建的，看起来像：
void CoordinateConversionService::convert( SourceOrTarget::Enum sourceDirection, SourceOrTarget::Enum targetDirection, CoordinateTuple* sourceCoordinates, Accuracy* sourceAccuracy, CoordinateTuple& targetCoordinates, Accuracy& targetAccuracy )
我是我工作中的实习生，我还没有使用过这个，所以我的理解非常有限，还有我对VB的使用（我是C++/ C# 家伙）。这里有几个问题：
1）看看Dllimport，似乎参数之外的最后一部分是返回类型。来自另一个站点的示例代码：
<DllImport("advapi32.dll")> _
Public Function GetUserName( _
ByVal lpBuffer As StringBuilder, _
ByRef nSize As Integer) As Boolean
返回类型是“As Boolean”吗？如果是这样，我尝试使用“Sub”，它显示“关键字未命名类型”。因此，我为什么要考虑声明，因为我似乎可以返回 void/sub 作为返回类型。
2）尝试使用类型“CooperativeTuple”和“Accuracy”给我带来了问题，说它们没有定义。既然我认为我无法真正定义它们，那么我该如何解决这个问题，而且它们是指针这一事实又如何呢？另外 - 我无法以任何方式修改 C++ 代码，所以我所拥有的就是我所拥有的。
I am working on a project where I have to import a DLL file into a VB project that was created a few years back. The DLL was created in C++, and looks like:
void CoordinateConversionService::convert( SourceOrTarget::Enum sourceDirection, SourceOrTarget::Enum targetDirection, CoordinateTuple* sourceCoordinates, Accuracy* sourceAccuracy, CoordinateTuple& targetCoordinates, Accuracy& targetAccuracy )
I am an intern at my job, and I haven't had to use this yet, so my understanding is extremely limited, along with my usage of VB (I'm a C++/C# guy). Here are a few questions:
1) Looking at Dllimport, it seems like the last part outside of the parameters is a return type. Example code from another site:
<DllImport("advapi32.dll")> _
Public Function GetUserName( _
ByVal lpBuffer As StringBuilder, _
ByRef nSize As Integer) As Boolean
Is "As Boolean" the return type? If so, I tried using "Sub" and it says "Keyword does not name a type." Hence why I looked into declare, because it seems I CAN return void/sub as a return type.
2) Trying to use the types "CoordinateTuple" and "Accuracy" give me problems, saying that they aren't defined. How do I get around this since I don't think I can really define them, and what about the fact that they're pointers? Also - I cannot modify the C++ code in any way, so what I have is what I have.
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在 VB 中，您可以说
Public Function What (params) As ReturnType（与 C# 中的public ReturnType What(params)相同）或Public Sub What ( params)用于不返回任何内容的内容（在 C++/C# 中返回void）。如果您的函数/子函数采用自定义类型，您还需要声明这些类型的 .NET 等效项。这会使 PInvoke 工作困难。 互操作助手等工具可以提供帮助。
In VB you say either
Public Function Whatever (params) As ReturnType(which is the same aspublic ReturnType Whatever(params)in C#) orPublic Sub Whatever (params)which is for things that don't return anything (returnvoidin C++/C#).If your function/sub takes custom types you will need to declare .NET equivalents to those as well. This can make PInvoke hard work. Tools like the interop assistant can help.
对于自定义类型，您可能必须在托管 C++ 中创建一个包装器，它既能够使用本机 C++ API，又能够公开托管 API。尽管已过时，但可以在此处找到演练：
For the custom types, you may have to create a wrapper in managed C++, which has the ability both to consume native C++ APIs and expose managed APIs. Although dated, a walkthrough can be found here: