Silverlight5通过P/Invoke调用自定义C/C++ DLL(Lua)
上一篇《Silverlight5通过P/Invoke调用系统win32的三个示例》展示了silverlight5通过P/Invoke调用系统win32的三个示例，本篇给出自定义win32 dll及其在Silverlight5中调用的代码。
注1：为了确保silverilght5在浏览器或桌面上成功调用win32 DLL，必须在项目属性中勾选相应的权限：
勾选Enable running application out of the browser及其Require elevated trust when running in-browser
勾选Require elevated trust when running in-browser
注2：win32 dll文件编译后放在\windows\system32或\windows\system目录下，win7 x64的系统放在后者。
注3：winform/wpf中调用类似
.h
// The following ifdef block is the standard way of creating macros which make exporting // from a DLL simpler. All files within this DLL are compiled with the MYDLL_EXPORTS // symbol defined on the command line. This symbol should not be defined on any project // that uses this DLL. This way any other project whose source files include this file see // MYDLL_API functions as being imported from a DLL, whereas this DLL sees symbols // defined with this macro as being exported. #ifdef MYDLL_EXPORTS #define MYDLL_API __declspec(dllexport) #else #define MYDLL_API __declspec(dllimport) #endif
struct HHFC_SET
{
;char* UID;
int code;
};
// This class is exported from the MyDLL.dll
class MYDLL_API CMyDLL {
public:
CMyDLL(void);
// TODO: add your methods here.
};
//extern MYDLL_API int nMyDLL;
extern "C" MYDLL_API int nMyDLL;
extern "C" MYDLL_API float fnMyDLL(float x ,float y);// 注意得加上extern "C"，否则无法P/Invoke
.cpp
#include "stdafx.h" #include "MyDLL.h"
#include <iostream>
#include "LuaPlus.h"
#include "LuaPlusHelper.h"
#pragma comment(lib,"LuaPlusLib.lib")
using namespace LuaPlus;
using namespace std;
// This is an example of an exported variable
MYDLL_API int nMyDLL=0;
// This is an example of an exported function.
MYDLL_API float fnMyDLL(float x ,float y)
{
//调用Lua脚本并计算
string str;
str.append("function Add(x, y)\n");
str.append(" return x*y;\n");
str.append("end\n");
int iret = state->DoString(str.c_str());// state->DoFile("a.lua");
LuaFunction Add = state->GetGlobal("Add");
float myret = Add(x,y);
return myret;
}
extern "C" __declspec(dllexport) int WINAPI add()
{
return 101;
}
extern "C" __declspec(dllexport) int WINAPI add2(HHFC_SET* stru )
{
stru->UID="this is a win32 test about struct";
stru->code=3;
return 1;
}
extern "C" __declspec(dllexport) float* WINAPI add3()
{
float* num=(float*)malloc(4);
num[0]=11.2f;
num[1]=21.3f;
num[2]=33.5f;
num[3]=46.2f;
return num;
}
// This is the constructor of a class that has been exported.
// see MyDLL.h for the class definition
CMyDLL::CMyDLL()
{
return;
}
.xaml
<Grid x:Name="LayoutRoot" Background="White">
<StackPanel Orientation="Horizontal" VerticalAlignment="Top" Margin="24,24,0,0">
<TextBlock Name="textBlock1" Text="add 函数结果:" Height="23" />
<TextBox Name="textBox1" Width="120" Height="23" />
</StackPanel>
<StackPanel Orientation="Horizontal" VerticalAlignment="Top" Margin="24,64,0,0">
<TextBlock Name="textBlock2" Text="fnMyDLL函数结果:" Height="23"/>
<TextBox Name="textBox2" VerticalAlignment="Top" Width="120" Height="23"/>
</StackPanel>
<Button Content="Button" Height="32" Margin="120,101,202,0" Name="button1" VerticalAlignment="Top" Width="78" Click="button1_Click" />
</Grid>
.cs
public partial class MainPage : UserControl
{
[DllImportAttribute("user32.dll", EntryPoint = "MessageBoxW")]
public static extern int MessageBoxW(int hWnd, [In][MarshalAs(UnmanagedType.LPWStr)] string lpText, [In][MarshalAs(UnmanagedType.LPWStr)] string lpCaption, int uType);
[DllImport("MyDll.dll", EntryPoint = "add", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall, SetLastError = false)]
public static extern int add();
[DllImport("MyDll.dll", EntryPoint = "fnMyDLL", CharSet = CharSet.Auto, CallingConvention = CallingConvention.Winapi, SetLastError = false)]
public static extern float fnMyDLL(float x,float y);
[DllImport("MyDLL.dll", EntryPoint = "add2", CharSet = CharSet.Auto, CallingConvention = CallingConvention.Winapi, SetLastError = false)]
public static extern int add2(ref HHFC_SET stru);
[DllImport("MYDLL.dll", EntryPoint = "add3", CharSet = CharSet.Auto, CallingConvention = CallingConvention.Winapi, SetLastError = false)]
public static extern IntPtr add3();
//EntryPoint: 指定要调用的 DLL 入口点。默认入口点名称是托管方法的名称 。
//CharSet: 控制名称重整和封送 String 参数的方式 (默认是UNICODE)
//CallingConvention指示入口点的函数调用约定(默认WINAPI)
//SetLastError 指示被调用方在从属性化方法返回之前是否调用 SetLastError Win32 API 函数 (C#中默认false )
public MainPage()
{
InitializeComponent();
}
private void button1_Click(object sender, RoutedEventArgs e)
{
this.textBox1.Text = add().ToString();
this.textBox2.Text = fnMyDLL(12,2).ToString();
MessageBoxW(0, "提交成功", "温馨提示", 0);
HHFC_SET stru = new HHFC_SET();
stru.Uid = "";
Console.WriteLine(stru.Uid);
int a = add2(ref stru);
Console.WriteLine(stru.Uid);
IntPtr d = add3();
float[] bytes2 = new float[Marshal.SizeOf(d)];
Marshal.Copy(d, bytes2, 0, 4);
}
}
[StructLayout(LayoutKind.Sequential)]
public struct HHFC_SET
{
[MarshalAs(UnmanagedType.LPStr)]
public String Uid;
[MarshalAs(UnmanagedType.I4)]
public int code;
}
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.net调用C DLL
编写C程序如下：
#include "stdio.h"
__declspec(dllexport) void MyFun() { printf("this is a dll\n"); }
保存，取名为My.C
运行 VS 命令提示，Cl /c 路径/My.c
运行以后会生成 My.Obj，默认在vs安装文件夹的VC目录下
再运行 link/dll 路径/My.obj
在同一个目录会生成My.dll
在C#中调用：
将dll复制到bin目录，编写如下C#代码：
static void Main(string[] args)
{
MyFun();
}
[DllImport("My.dll")]
public extern static void MyFun();
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C#传委托给C的函数指针调用问题
C代码如下：
#include "stdio.h"
__declspec(dllexport) int Call(int (*qq)(int num),char * str)
{
printf(str);
return qq(123);
}
多次验证发现在C#中传委托给C中的函数指针，如果委托不带参数则都能成功运行，但是委托一带参数不管是int参数还是string参数或者其他参数，都会报“ 尝试读取或写入受保护的内存。这通常指示其他内存已损坏”的错误，找了一天才找到解决方法，既在C#的委托声明上加[UnmanagedFunctionPointer(CallingConvention.Cdecl)]，正确调用如下：
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
public delegate int MyDeg(int num);
class Program
{
static void Main(string[] args)
{
try
{
MyDeg myd = new MyDeg(FF);
Console.WriteLine(Call(myd, "helloworld"));
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
static int FF(int num)
{
Console.WriteLine(num);
return num + 1;
}
[DllImport("my.dll", EntryPoint = "Call")]
public extern static int Call(MyDeg mm ,string str);
}
