C#调用非托管DLL参数传递备忘录

非托管参数为const MyStruct* myStructInstance和Mystruct* myStructInstance的时候,C#程序都可以通过ref MyStruct myStructInstance来传递参数

2,C++,C中的long都为4字节数,转到C#中都为int型

例如

C,C++中的定义

typedef struct HS_RECT

{

long left;

long top;

long right;

long bottom;

}HS_RECT;

放到C#中应为

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]

public struct HS_RECT

{

public int left;

public int top;

public int right;

public int bottom;

};

3,结构体转换为指针类型

//定义eyePoint为一个HS_EyePoint结构体

FeatureData.HS_EyePoint eyePoint;

//定义pEye 为一个指向HS_EyePoint的指针

IntPtr pEye = Marshal.AllocCoTaskMem(Marshal.SizeOf(typeof(FeatureData.HS_EyePoint)) );

//把eyePoint转换为pEye,即让pEye指向eyePoint的地址

Marshal.StructureToPtr(eyePoint, pEye, true);

//程序处理

nRetCode = HS_LocateEye(pbyGrayImage, nImageWidth[0], nImageHeight[0],

ref rcFace, ref eyePoint);

//处理完毕,把指针还原为结构体

eyePoint = (FeatureData.HS_EyePoint) Marshal.PtrToStructure(pEye, typeof(FeatureData.HS_EyePoint));

//释放指针指向的空间

Marshal.FreeCoTaskMem(pFace);

代码为:

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using System.Runtime.InteropServices;

namespace FeatureExtraction

{

public partial class Form1 : Form

{

//调用C DLL 中的函数

[DllImport("HISIGN_FaceID.dll", EntryPoint = "HS_InitFaceIDSDK", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]

public static extern int HS_InitFaceIDSDK(FeatureData.HS_FACEMODE enMode);

[DllImport("HISIGN_FaceID.dll", EntryPoint = "HS_GetFaceFeatureSize", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]

public static extern int HS_GetFaceFeatureSize();

[DllImport("HISIGN_FaceID.dll", EntryPoint = "HS_GetImageSize", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]

public static extern int HS_GetImageSize(string strImagePathName, int[] nImageWidth, int[] nImageHeight);

//int __stdcall HS_GetImageSize(const char *strImagePathName, int *nImageWidth, int *nImageHeight);

[DllImport("HISIGN_FaceID.dll", EntryPoint = "HS_GetGrayImageFromFile", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]

public static extern int HS_GetGrayImageFromFile(string strImagePathName, Byte[] pbyOutGrayImage);

//int __stdcall HS_GetGrayImageFromFile(const char *strImagePathName, Byte *pbyOutGrayImage);

[DllImport("HISIGN_FaceID.dll", EntryPoint = "HS_FaceDetection", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]

public static extern int HS_FaceDetection(Byte[] pbyGrayImage, int nImageWidth, int nImageHeight, int nMinFaceSize,

int nMaxFaceSize, ref FeatureData.HS_FaceCandidate pOutFaceCand, int[] nFaceNum);

//int __stdcall HS_FaceDetection(const Byte *pbyGrayImage, int nImageWidth, int nImageHeight, int nMinFaceSize,

// int nMaxFaceSize, HS_FaceCandidate *pOutFaceCand, int *nFaceNum);

[DllImport("HISIGN_FaceID.dll", EntryPoint = "HS_LocateEye", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]

public static extern int HS_LocateEye(Byte[] pbyGrayImage, int nImageWidth, int nImageHeight, ref FeatureData.HS_RECT pFaceRect, ref FeatureData.HS_EyePoint pEyePoint);

//int __stdcall HS_LocateEye(const Byte *pbyGrayImage, int nImageWidth, int nImageHeight,

// const HS_RECT *pFaceRect, HS_EyePoint *pEyePoint);

[DllImport("HISIGN_FaceID.dll", EntryPoint = "HS_FaceExtractionByEyepos", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]

public static extern int HS_FaceExtractionByEyepos(Byte[] pbyGrayImage, int nImageWidth, int nImageHeight, ref FeatureData.HS_EyePoint pEyePoint, Byte[] pbyFeature);

//int __stdcall HS_FaceExtractionByEyepos(const Byte *pbyGrayImage, int nImageWidth, int nImageHeight,

// const HS_EyePoint *pEyePoint, Byte *pbyFeature);

[DllImport("HISIGN_FaceID.dll", EntryPoint = "HS_UninitFaceIDSDK", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]

public static extern int HS_UninitFaceIDSDK();

//int __stdcall HS_UninitFaceIDSDK();

public Form1()

{

InitializeComponent();

}

private void button2_Click(object sender, EventArgs e)

{

int retCODE = GetDone();

}

private int GetDone()

{

FeatureData.HS_FACEMODE enMode; // 人脸识别工作模式

int nRetCode; // 返回值代码

FeatureData.HS_FaceCandidate[] pFaceCand; // 人脸检测候选

int[] nFaceNum = new int[1]; // 检测到的人脸数目

string strImagePath = @"C:\Documents and Settings\kingking\My Documents\My Pictures\me\344.jpg"; // 人脸图像名

int[] nImageWidth = new int[1]; // 图像宽度、高度

int[] nImageHeight = new int[1];

Byte[] pbyGrayImage = null; // 灰度图像缓冲区

FeatureData.HS_EyePoint eyePoint=new FeatureData.HS_EyePoint(); // 眼睛位置

int nFeatSize; // 得到本版本SDK的人脸特征的字节数

Byte[] pbyFeatures = null; // 特征缓冲区

// 初始化SDK

enMode = FeatureData.HS_FACEMODE.HS_Verify;

nRetCode = HS_InitFaceIDSDK(enMode);

if (nRetCode != FeatureData.HISIGN_ERR_NONE)

{

return nRetCode;

}

// 得到人脸特征的字节大小

nFeatSize = HS_GetFaceFeatureSize();

// 从文件中读取人脸图像，将人脸图像转化成灰度图像

nRetCode = HS_GetImageSize(strImagePath, nImageWidth, nImageHeight);

pbyGrayImage = new Byte[nImageWidth[0] * nImageHeight[0]];

nRetCode = HS_GetGrayImageFromFile(strImagePath, pbyGrayImage);

pFaceCand = new FeatureData.HS_FaceCandidate[100]; // 分配人脸检测结果的内存

// 进行人脸检测

nRetCode = HS_FaceDetection(pbyGrayImage, nImageWidth[0], nImageHeight[0], 20,

(nImageWidth[0] >= nImageHeight[0] ? nImageHeight[0] : nImageWidth[0]), ref pFaceCand[0], nFaceNum);

// 对每个检测到的人脸进行眼睛定位

for (int i = 0; i < nFaceNum[0]; ++i)

{

FeatureData.HS_RECT rcFace;

rcFace.left = pFaceCand[i].trueleft;

rcFace.top = pFaceCand[i].truetop;

rcFace.right = pFaceCand[i].trueright;

rcFace.bottom = pFaceCand[i].truebottom;

//IntPtr prcFace = Marshal.AllocCoTaskMem(Marshal.SizeOf(rcFace));

//Marshal.StructureToPtr(rcFace, prcFace, false);

IntPtr pFace = Marshal.AllocCoTaskMem(Marshal.SizeOf(typeof(FeatureData.HS_RECT)) );

Marshal.StructureToPtr(rcFace, pFace, true);

IntPtr pEye = Marshal.AllocCoTaskMem(Marshal.SizeOf(typeof(FeatureData.HS_EyePoint)) );

nRetCode = HS_LocateEye(pbyGrayImage, nImageWidth[0], nImageHeight[0],

ref rcFace, ref eyePoint);

//eyePoint = (FeatureData.HS_EyePoint) Marshal.PtrToStructure(pEye, typeof(FeatureData.HS_EyePoint));

Marshal.FreeCoTaskMem(pFace);

Marshal.FreeCoTaskMem(pEye);

// 进行特征提取

pbyFeatures = new Byte[nFeatSize];

nRetCode = HS_FaceExtractionByEyepos(pbyGrayImage, nImageWidth[0],

nImageHeight[0], ref eyePoint, pbyFeatures);

pbyFeatures = null;

//Marshal.FreeHGlobal(prcFace);

}

pbyGrayImage = null;

pFaceCand = null;

// 释放SDK资源

nRetCode = HS_UninitFaceIDSDK();

return nRetCode;

}

}