C#中调用C++代码

C# 中调用C++代码

int 类型

[DllImport(“MyDLL.dll")]

//返回个int 类型

public static extern int mySum(int a1,int b1);

//DLL中申明

extern “C”__declspec(dllexport) int WINAPI mySum(int a2,int b2)

{

//a2 b2不能改变a1 b1

//a2=..

//b2=...

return a+b;

}

//参数传递int 类型

public static extern int mySum(ref int a1,ref int b1);

//DLL中申明

extern “C”__declspec(dllexport) int WINAPI mySum(int *a2,int*b2)

{

//可以改变 a1, b1

*a2=...

*b2=...

return a+b;

}

DLL 需传入char *类型

[DllImport(“MyDLL.dll")]

//传入值

public static extern int mySum(string astr1,string bstr1);

//DLL中申明

extern “C”__declspec(dllexport) int WINAPI mySum(char * astr2,char *bstr2)

{

//改变astr2 bstr 2 ，astr1bstr1不会被改变

return a+b;

}

DLL 需传出char *类型

[DllImport(“MyDLL.dll")]

// 传出值

public static extern int mySum(StringBuilder abuf, StringBuilder bbuf );

//DLL中申明

extern “C”__declspec(dllexport) int WINAPI mySum(char * astr,char *bstr)

{

//传出char *　改变astr　bstr-->abuf, bbuf可以被改变

return a+b;

}

DLL 回调函数

BOOL EnumWindows(WNDENUMPROClpEnumFunc, LPARAM lParam)

using System;

usingSystem.Runtime.InteropServices;

public delegate boolCallBack(int hwnd, int lParam); //定义委托函数类型

public classEnumReportApp

{

[DllImport("user32")]

public static extern intEnumWindows(CallBack x, int y);

public static void Main(){

CallBack myCallBack = newCallBack(EnumReportApp.Report); EnumWindows(myCallBack,0);

}

public static bool Report(inthwnd, int lParam)

{

Console.Write("Window handle is");

Console.WriteLine(hwnd); returntrue;

}

}

DLL 传递结构

BOOL PtInRect(const RECT *lprc,POINT pt);

usingSystem.Runtime.InteropServices;

[StructLayout(LayoutKind.Sequential)]

public struct Point{

public int x;

public int y;

}

[StructLayout(LayoutKind.Explicit)]

public struct Rect

{

[FieldOffset(0)] public intleft;

[FieldOffset(4)] public inttop;

[FieldOffset(8)] public intright;

[FieldOffset(12)] public intbottom;

}

Class XXXX {

[DllImport("User32.dll")]

public static extern boolPtInRect(ref Rect r, Point p);

}