How to add a thread in MFC

In this paper, we introduce a new method in MFC An operation often encountered in programming ： How to add a thread ？ I don't say much nonsense , Go straight to step .

First, create a new one thread_op.h and thread_op.c file .

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 //  This macro is critical 

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;


 /*  Pass the result to the main thread  */
 pStruct->pDlg->SendMessage(WM_CONF_IMGPROC, 0, (long)* testResult);
}

next , Add an object to the class in the dialog header file .

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

Establish the connection with the main dialog box in the initialization interface of the dialog box main program ：

ImgThreadPra.pDlg = this;

After that, some operations that you want to perform after clicking the button are left to other threads to operate , such as ：

void CguiDlg::OnBnClickedOk()
{
 // TODO:  Add control notification handler code here 
 CDialogEx::OnOK();
 
 pTestThread = AfxBeginThread(imgProcThread, &imgTestThreadPra);
}

Last in windowProc Medium switch Add case Processing can be ：

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);
}