c# - 从 C# 调用 C++ 代码时出现 System.EntryPointNotFoundException

Question

//------------------------------------ C#代码------ ------------------------------

[DllImport("MarshallStringsWin32.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
extern static void Test([MarshalAs(UnmanagedType.AnsiBStr)] out String str);

[DllImport("MarshallStringsWin32.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
extern static void FreeString([MarshalAs(UnmanagedType.AnsiBStr)] String str);

static void Main(string[] args)
{
    String str;
    Test(out str);
    FreeString(str);
}

//------------------------------------ C++代码------ ------------------------------

void Test(__out BSTR* str)
{
   const std::string stdStr = "The quick brown fox jumps over the lazy dog";
   _bstr_t bstrStr = stdStr.c_str();
   *str = bstrStr.copy();
}

void FreeString(BSTR str)
{
   SysFreeString(str);
}

我在调用 Test() 时收到 System.EntryPointNotFoundException。有人会知道我做错了什么吗？这是编码字符串的正确方法吗？

Answer 1

也许你需要在头文件中添加c++代码的代码:

 extern "C" void __declspec(dllexport) FreeString(BSTR str);

 extern "C" void __declspec(dllexport) Test(BSTR* str);