How to add a thread in MFC

This article introduces an operation that is often encountered in MFC programming: how to add a thread? Without further ado, let's go directly to the steps.

First create a new thread_op.h and thread_op.c files.

I added an image processing thread here, the header file is as follows:

#pragma once
#include <stdlib.h>
#include "afxwin.h"
#define WM_CONF_IMGPROC WM_USER+101 // 该宏至关重要

enum TEST_RES_CODE {
    
    
	TR_FAIL,
	TR_SUCCESS,
	TR_EXCEPTION,
};

typedef struct TestResult {
    
    
	bool isbrpass;
	bool isdarkpass;
	long brnum;
}TestResult;

typedef struct ImgThreadPra {
    
    
	CWnd* pDlg;
	int size;
}ImgThreadPra;

UINT imgProcThread(LPVOID pParam);

The corresponding implementation files are as follows:

#include <stdlib.h>
#include "afxwin.h"
#include "thread_op.h"

UINT imgProcThread(LPVOID pParam)
{
    
    
	ImgThreadPra* pStruct = (ImgThreadPra*)pParam;
	if (pStruct == NULL || pStruct->pDlg == NULL)
		return -1;


	/* 将结果传递给主线程 */
	pStruct->pDlg->SendMessage(WM_CONF_IMGPROC, 0, (long)* testResult);
}

Next, add the object to the class in the dialog header file.

CWinThread *pTestThread;
TestThreadPra imgTestThreadPra;
LRESULT WindowProc(UINT message, WPARAM WParam， LPARAM lParam);

The connection with the main dialog box is established in the initialization interface of the main program of the dialog box:

ImgThreadPra.pDlg = this;

After that, some operations that you want to perform after clicking the button are thrown to other threads for operation , such as:

void CguiDlg::OnBnClickedOk()
{
    
    
	// TODO: 在此添加控件通知处理程序代码
	CDialogEx::OnOK();
	
	pTestThread = AfxBeginThread(imgProcThread, &imgTestThreadPra);
}

Finally, add case processing to the switch in windowProc :

LRESULT testTool::WindowProc(UINT message, WPARAM WParam， LPARAM lParam)
{
    
    
	TestResult *ret = NULL;
	switch WM_CONF_IMGPROC:
		testResult = (TestResult*)lParam;
		break;
		
	return CDialog::WindowProc(message, wParam, lParam);
}