C#调用C++方法,C#使用c++方法返回类或结构体。
1. 在c++中定义结构体,类,处理方法;要给c#调用的方法要加extern “C” __declspec(dllexport) 修饰
#include "stdafx.h"
#define EXPORT_DLL extern "C" __declspec(dllexport)
EXPORT_DLL
int
Add(``int
a,``int
b)
{
return
a + b;
}
struct
Bar
{
public
:
int
id;
char``* name;
};
EXPORT_DLL
void
GetBar(Bar& bar)
{
bar.id = 10;
bar.name =
"hi bar 中文了"``;
}
class
Foo
{
public
:
int
id;
char``* name;
};
EXPORT_DLL
void
GetFoo(Foo& foo)
{
foo.id = 100;
foo.name =
"I'm 傻瓜"``;
}
2. 在C#中使用C++方法,首先需要定义C++中的Foo(在c++中定义为类class),Bar(在C++中定义为struct)对应的数据结构struct;然后定义extern的方法,如下代码所示:
using
System;
using
System.Collections.Generic;
using
System.Text;
using
System.Runtime.InteropServices;
namespace
UseCppDll
{
[System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
public
struct
Bar
{
/// int
public
int
id;
/// char*
[System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)]
public
string
name;
}
[System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
public
struct
Foo
{
/// int
public
int
id;
/// char*
[System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)]
public
string
name;
}
class
Program
{
[DllImport(``"CppDll.dll"``,EntryPoint=``"Add"``)]
extern
static
int
Add(``int
a,
int
b);
[DllImport(``"CppDll.dll"``, EntryPoint =
"GetBar"``,CharSet=CharSet.Ansi)]
extern
static
void
GetBar(``ref
Bar bar);
[DllImport(``"CppDll.dll"``, EntryPoint =
"GetFoo"``, CharSet = CharSet.Ansi)]
extern
static
void
GetFoo(``ref
Foo foo);
static
void
Main(``string``[] args)
{
Console.WriteLine(Add(5,4));
Bar b =
new
Bar();
GetBar(``ref
b);
Console.WriteLine(``"b's id is "
+ b.id);
Console.WriteLine(``"b's name is "
+ b.name);
Foo f =
new
Foo();
GetFoo(``ref
f);
Console.WriteLine(``"f's id is "
+ f.id);
Console.WriteLine(``"f's name is "
+ f.name);
Console.Read();
}
}
}
C++中的类或者结构在C#中的定义代码可以使用微软提供的工具(P/Invoke Interop Assistant)生成。
在运行C#程序前要把C++dll复制到C#程序运行目录下。