C ++ / cli to c ++：错误与“void（__stdcall *）（int i，std :: string str）”不兼容。 [英] C++/cli to c++: Error s incompatible with "void (__stdcall *)(int i, std::string str)"

问题描述

我是C ++ / cli的新手，请原谅我的愚蠢的问题或核心错误：

我的C ++ / CLI类库被C＃调用只有一个方法：

ThreadsCppWrapper.h

 命名空间命名空间ThreadsCppWrapper {
 
 public ref class ThreadsCppWrapperClass 
 {
 public：
 ThreadsCppWrapperClass（）; // Constructor 
 
 System :: String ^ mytrainOp（System :: MulticastDelegate ^ callbackfunction）; 
 private：
 MyThreadsCpp :: MyThreadsCppClass * ptr; 
}; 
} 
  

ThreadsCppWrapper.cpp

  System :: String ^ ThreadsCppWrapper :: ThreadsCppWrapperClass :: mytrainOp（System :: MulticastDelegate ^ callbackfunction）{
 
 System :: String ^ toReturn = gcnew System： ：串（）; 
 
 msclr :: interop :: marshal_context context; 
 System :: IntPtr intPtr = System :: Runtime :: InteropServices :: Marshal :: GetFunctionPointerForDelegate（callbackfunction）; 
 if（intPtr！= System :: IntPtr :: Zero）
 {
 myUpdateProgress functPtr = static_cast< myUpdateProgress>（intPtr.ToPointer（））; 
 string stdstringResult = ptr-> train（functPtr）; // Error Here // ERRORLINE 
 
 // toReturn = context.marshal_as< System :: String ^>（stdstringResult）; 
} 
 else 
 {
 System :: Console :: WriteLine（Error：Could not cast delegate !!）; 
} 
 return toReturn; 
} 
  

从c ++ / cli类调用的C ++类是：

MyThreadsCpp.h

 命名空间MyThreadsCpp {
 
 class MyThreadsCppClass 
 {
 public：
 MyThreadsCppClass（）; 
 string train（void（CALLBACK * myUpdateProgress）（int i，string str））; 
}; 
 
} 
  

MyThreadsCpp.cpp

  string MyThreadsCpp :: MyThreadsCppClass :: train（void（CALLBACK * myUpdateProgress）（int i，string str））{
 
 double sum = 0.0; 
 long max = 100 * 1000; 
 int perc = 0 ;; 
 string trainstat =训练状态：开始训练...; 
 ostringstream oss; 
 
 myUpdateProgress（perc，trainstat）; 
 for（long n = 0; n  sum + = 4.0 * pow（-1.0，n）/（2 * n + 1.0） 
 int rem = n％（max / 10）; 
 if（rem == 0）{
 perc = 100 * n / max; 
 cout<< perc<< ％< endl; 
 / *报告完成状态* / 
 oss< 训练状态：< ; 
 myUpdateProgress（perc，oss.str（））; 
} 
} 
 cout<< 100％<< endl; 
 ostringstream oss; 
 oss<< Result =<<和; 
 return oss.str（）; 
} 
  

它编译得很好。

Intellisense包装类中的错误ERRORLINE：
1myUpdateProgress类型的参数与ThreadsCppWrapper.cpp中的类型为void（__stdcall *）（int i，std :: string str）的参数不兼容

专家，请帮助。

解决方案

c> std :: string 和 System :: String ^ 。您必须将它们转换为一种类型。强制转换类型或函数指针/回调将不会工作 - 如果不是编译时，它将在运行时断开。

I am new to C++/cli so please excuse me for silly questions or core mistakes:

My C++/CLI class Library that is called by C# has only one method:

ThreadsCppWrapper.h

namespace namespace ThreadsCppWrapper {

public ref class ThreadsCppWrapperClass
    {
        public:
        ThreadsCppWrapperClass(); // Constructor

        System::String^ mytrainOp(System::MulticastDelegate^ callbackfunction);
    private:
        MyThreadsCpp::MyThreadsCppClass* ptr;
    };
}

ThreadsCppWrapper.cpp

System::String^ ThreadsCppWrapper::ThreadsCppWrapperClass::mytrainOp(System::MulticastDelegate^ callbackfunction){

System::String^ toReturn = gcnew System::String("");

msclr::interop::marshal_context context;
System::IntPtr intPtr = System::Runtime::InteropServices::Marshal::GetFunctionPointerForDelegate(callbackfunction);
if (intPtr != System::IntPtr::Zero)
{
    myUpdateProgress functPtr = static_cast<myUpdateProgress>(intPtr.ToPointer());
    string stdstringResult = ptr->train(functPtr); // Error Here   // ERRORLINE

    //toReturn = context.marshal_as<System::String^>(stdstringResult);
}
else
{
    System::Console::WriteLine("Error: Could not cast delegate!!");
}
return toReturn;
}

The C++ class that is called from c++/cli class is:

MyThreadsCpp.h

namespace MyThreadsCpp{

class MyThreadsCppClass
{
public:
    MyThreadsCppClass();
    string train(void(CALLBACK *myUpdateProgress)(int i, string str));
};

}

MyThreadsCpp.cpp

string MyThreadsCpp::MyThreadsCppClass::train(void(CALLBACK *myUpdateProgress)(int i, string str)){

double sum = 0.0;
long max = 100 * 1000;
int perc = 0;;
string trainstat = "Training Status: Starting Training...";
ostringstream oss;

    myUpdateProgress(perc, trainstat);
for (long n = 0; n < max; n++){
    sum += 4.0*pow(-1.0, n) / (2 * n + 1.0);
    int rem = n % (max/10);
    if (rem == 0){
        perc = 100 * n / max;
        cout << perc << "%" << endl;
        /* report completion status */
        oss << "Training Status: " << perc;
        myUpdateProgress(perc, oss.str());
    }
}
cout << "100%" << endl;
ostringstream oss;
oss << "Result = " << sum;
return oss.str();
}

It compiles fine.

Intellisense Error in wrapper class ERRORLINE: 1 argument of type "myUpdateProgress" is incompatible with parameter of type "void (__stdcall *)(int i, std::string str)" in ThreadsCppWrapper.cpp

Experts, Please help.

解决方案

You cannot use std::string and System::String^ interchangeably. You must convert them to one type. Forceful conversion of type or the function-pointer/callback won't work - it will break at runtime, if not compile time.

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