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MFC，C++，海康SDK，回调，轮询

news 2025/8/22 8:09:56

二次开发，但是找遍了所有的技术文档，都没有找到实现回调取图的完整流程的教程，文档。痛苦不堪，虽然轮询取图在技术文档中实现了，但是还是需要将其与其他很多功能分开。特此，本文将再次简单记录一下实现的过程。

1.一定要使用面向对象的方式。

创建一个相机类和一个主框架类，这里直接在其技术文件中可以找到复制粘贴即可。

然后现在讲述回调实现的源码。轮询技术文档提供，不赘述.

1. 修改对话框类头文件

首先在CImage_GrabDlg.h中添加必要的成员变量和函数声明：

// Image_GrabDlg.h
class CImage_GrabDlg : public CDialogEx
{// ... 其他已有代码protected:// 用于显示图像的静态控件句柄HWND m_hwndDisplay;// 图像数据相关unsigned char* m_pSaveImageBuf;unsigned int m_nSaveImageBufSize;CRITICAL_SECTION m_hSaveImageMux;MV_FRAME_OUT_INFO_EX m_stImageInfo;// 回调函数声明static void __stdcall ImageCallBackEx(unsigned char* pData, MV_FRAME_OUT_INFO_EX* pFrameInfo, void* pUser);void OnImageCallBack(unsigned char* pData, MV_FRAME_OUT_INFO_EX* pFrameInfo);// 初始化函数void DisplayWindowInitial();// ... 其他已有成员
};

2. 修改对话框类实现文件

2.1 初始化部分

// Image_GrabDlg.cpp
CImage_GrabDlg::CImage_GrabDlg(CWnd* pParent /*=NULL*/): CDialogEx(IDD_IMAGE_GRAB_DIALOG, pParent), m_pcMyCamera(NULL), m_nDeviceCombo(0), m_bOpenDevice(FALSE), m_bStartGrabbing(FALSE), m_hGrabThread(NULL), m_bThreadState(FALSE), m_nTriggerMode(MV_TRIGGER_MODE_OFF), m_pSaveImageBuf(NULL), m_nSaveImageBufSize(0)
{m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);memset(&m_stImageInfo, 0, sizeof(MV_FRAME_OUT_INFO_EX));InitializeCriticalSection(&m_hSaveImageMux);
}CImage_GrabDlg::~CImage_GrabDlg()
{DeleteCriticalSection(&m_hSaveImageMux);if (m_pSaveImageBuf){free(m_pSaveImageBuf);m_pSaveImageBuf = NULL;}
}

2.2 回调函数实现

// 静态回调函数
void __stdcall CImage_GrabDlg::ImageCallBackEx(unsigned char* pData, MV_FRAME_OUT_INFO_EX* pFrameInfo, void* pUser)
{if (!pData || !pFrameInfo || !pUser){return;}CImage_GrabDlg* pThis = (CImage_GrabDlg*)pUser;pThis->OnImageCallBack(pData, pFrameInfo);
}// 实际处理回调的成员函数
void CImage_GrabDlg::OnImageCallBack(unsigned char* pData, MV_FRAME_OUT_INFO_EX* pFrameInfo)
{// 保存图像数据EnterCriticalSection(&m_hSaveImageMux);if (NULL == m_pSaveImageBuf || pFrameInfo->nFrameLen > m_nSaveImageBufSize){if (m_pSaveImageBuf){free(m_pSaveImageBuf);m_pSaveImageBuf = NULL;}m_pSaveImageBuf = (unsigned char*)malloc(pFrameInfo->nFrameLen);if (m_pSaveImageBuf == NULL){LeaveCriticalSection(&m_hSaveImageMux);return;}m_nSaveImageBufSize = pFrameInfo->nFrameLen;}memcpy(m_pSaveImageBuf, pData, pFrameInfo->nFrameLen);memcpy(&m_stImageInfo, pFrameInfo, sizeof(MV_FRAME_OUT_INFO_EX));LeaveCriticalSection(&m_hSaveImageMux);// 在UI线程中更新显示if (m_hwndDisplay){MV_CC_IMAGE stImageData = {0};stImageData.nWidth = pFrameInfo->nWidth;stImageData.nHeight = pFrameInfo->nHeight;stImageData.enPixelType = pFrameInfo->enPixelType;stImageData.nImageLen = pFrameInfo->nFrameLen;stImageData.pImageBuf = pData;m_pcMyCamera->DisplayOneFrame(m_hwndDisplay, &stImageData);}
}

2.3 开始采集按钮实现

void CImage_GrabDlg::OnBnClickedButton4()
{if (FALSE == m_bOpenDevice || TRUE == m_bStartGrabbing || NULL == m_pcMyCamera){return;}// 注册回调函数int nRet = MV_CC_RegisterImageCallBackEx(m_pcMyCamera->outinterface(), CImage_GrabDlg::ImageCallBackEx, this);if (MV_OK != nRet){ShowErrorMsg(TEXT("Register image callback fail"), nRet);return;}// 设置采集模式为连续采集nRet = m_pcMyCamera->SetNetTransMode(MV_TRIGGER_MODE_OFF);if (MV_OK != nRet){ShowErrorMsg(TEXT("Set trigger mode fail"), nRet);return;}// 开始采集nRet = m_pcMyCamera->StartGrabbing();if (MV_OK != nRet){ShowErrorMsg(TEXT("Start grabbing fail"), nRet);return;}m_bStartGrabbing = TRUE;
}

2.4 停止采集按钮实现

void CImage_GrabDlg::OnBnClickedButton6()
{if (FALSE == m_bOpenDevice || FALSE == m_bStartGrabbing || NULL == m_pcMyCamera){return;}// 停止采集int nRet = m_pcMyCamera->StopGrabbing();if (MV_OK != nRet){ShowErrorMsg(TEXT("Stop grabbing fail"), nRet);return;}// 注销回调函数nRet = MV_CC_RegisterImageCallBackEx(m_pcMyCamera->outinterface(), NULL, NULL);if (MV_OK != nRet){ShowErrorMsg(TEXT("Unregister image callback fail"), nRet);}m_bStartGrabbing = FALSE;
}

3. 显示窗口初始化

void CImage_GrabDlg::DisplayWindowInitial()
{CWnd *pWnd = GetDlgItem(IDC_DISPLAY_STATIC);if (pWnd){m_hwndDisplay = pWnd->GetSafeHwnd();// 设置静态控件样式为SS_BITMAP，用于显示图像pWnd->ModifyStyle(0, SS_BITMAP);// 初始化显示黑色背景CRect rect;pWnd->GetClientRect(&rect);CDC *pDC = pWnd->GetDC();CBitmap bitmap;bitmap.CreateCompatibleBitmap(pDC, rect.Width(), rect.Height());pWnd->SetBitmap((HBITMAP)bitmap.Detach());pWnd->ReleaseDC(pDC);}
}