C# 委托，带有对 c++ 的字符串引用打回来
我编写了一个 C# 应用程序，它通过托管 c++ dll 使用非托管 c++ dll。 在非托管 dll 中，有一个回调，其参数之一是 std::string&。
我似乎找不到用托管 dll 包装它的正确方法。 当我使用 String^ 时，回调有效，但 C# 应用程序没有获取字符串中的任何内容。 当我使用 String^% 时，其他似乎不相关的地方开始崩溃（可能是内存损坏）。
所以我的问题是，这样做的正确方法是什么？
谢谢
I wrote a C# application that uses an unmanaged c++ dll via managed c++ dll.
In the unmanaged dll, there's a callback that one of its params is std::string&.
I can't seem to find the right way to wrap this with the managed dll.
When I use String^, the callback works, but the C# application does not get anything in the string.
When I used String^%, things started to crash in other places that does not seem to be related (maybe memory corruption).
So my question is, what's the right way to do this?
Thanks
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我无法在这里复制粘贴代码，但我会尝试再次解释。
我无法在托管 c++ 部分中使用封送处理，因为我没有调用函数，而是传递 ac# 委托以进行回调。
在非托管 dll 中，我有一个回调，需要这样的函数：
void Func(unsigned int, int, std:string &)。我的目标是将 ac# 委托从我的程序传递给该回调，因此在非托管代码中，
我做了一个像这样的委托：
delegate void DEL(unsigned int a, int b, String ^ c)和一个像这样的函数：void mFunc(DEL ^ del)，和该函数将委托编组到非托管回调订阅函数接受的 cb 中。 unsigned int 和 int 工作正常，但触发 C# 函数时字符串始终为""。I can't copy-paste code here, but I'll try to explain again.
I can't use marshaling in the managed c++ section because I'm not calling a function, but passing a c# delegate for a callback.
In the unmanaged dll, I have a callback that requires a function like this:
void Func(unsigned int, int, std:string &).My goal is to pass a c# delegate from my program to that callback, so in the unmanaged code,
I made a delegate like this:
delegate void DEL(unsigned int a, int b, String ^ c)and a function like:void mFunc(DEL ^ del), and that function marshal's the delegate into a cb that the unmanaged callback subscribe function accepts. The unsigned int and int works fine, but the string is always""when the C# function is triggered.发布一些代码将帮助我更好地理解并给出更好的答案；但 String^ 不会自动转换或编组到 std::string。您需要自己进行编组才能将字符串返回到 C# 代码。快速搜索可以提供有关如何执行此操作的详细信息。
http://msdn.microsoft.com/en-us/library/42zy2z41。 ASPX
Posting some code would help me understand better and give a better answer; but there is no automatic conversion or marshalling of String^ to std::string. You would need to do to marshalling yourself to get the string back to the C# code. A quick search can provide with details on how to do this.
http://msdn.microsoft.com/en-us/library/42zy2z41.aspx
我不相信编组可以处理 std::string。我认为您需要创建自己的传递 char * 的回调，然后在两者之间编写粘合代码。
此外，一旦委托被编组到回调中，该回调就不会被视为对委托可能来自的对象的引用。因此，如果委托不是静态方法，则需要在非托管回调的生命周期内将其填充到某个地方。
I don't believe that the marshalling can deal with std::string. I think you need to make your own callback that passes char * and then write the glue code between the two.
Also, once the delegate is marshalled into a callback, that callback does not count as a reference to the object that the delegate might have been made from. So if the delegate is not a static method, you need to stuff it somewhere for the lifetime of the unmanaged callback.