C # calls the C + + struct Body example

C + + definition

typedef struct STU
{
Public
int age;
Char name[20];
};

typedef struct NUM
{
int N1;
int N2;
};

extern "C" __declspec (dllexport) void Findinfo (stu& Stu)
{
Stu. Age = 10;
strcpy_s (Stu. Name, "Xu Xian");
}

extern "C" __declspec (dllexport) int Add (int a,int b)
{
return a + B;
}

extern "C" __declspec (dllexport) int getnumsum (num* Num)
{
return num->n1 + num->n2;
}

Need to redefine structure in C #

[System.Runtime.InteropServices.StructLayout (LayoutKind.Sequential)]
public struct STU
{
public int age;
[System.Runtime.InteropServices.MarshalAs (Unmanagedtype.byvaltstr,sizeconst =20)]
public string Name;
}

Note the correspondence of the data types in C # and C + +.

public struct Num
{
public int N1;
public int N2;
}

Declaring the calling function

[DllImport ("MyFuncDll.dll", EntryPoint = "Findinfo", CallingConvention = Callingconvention.cdecl,
CharSet = CharSet.Unicode)]
extern static void Findinfo (ref Stu STU);
[DllImport ("MyFuncDll.dll", EntryPoint = "Add", CallingConvention = callingconvention.cdecl)]
public extern static int Add (int a, int b);

[DllImport ("MyFuncDll.dll", EntryPoint = "Getnumsum", CallingConvention = callingconvention.cdecl)]
public extern static int getnumsum (ref num num);

Call Test

int re = ADD (1, 3);
num n = new num () {N1 = 1, N2 = 2};
int r = Getnumsum (ref n);
Stu Stu = new Usecppdll.stu ();
Findinfo (ref Stu);
MessageBox.Show (Stu. Name);

C # calls the C + + struct Body example