ChildProcApp.cpp

#include "pch.h"
#include "framework.h"
#include "ChildProc.h"
#include "ChildProcDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

BEGIN_MESSAGE_MAP(CChildProcApp, CWinApp)
	ON_COMMAND(ID_HELP, &CWinApp::OnHelp)
END_MESSAGE_MAP()

CChildProcApp::CChildProcApp()
{
}

CChildProcApp theApp;

BOOL CChildProcApp::InitInstance()
{
	CWinApp::InitInstance();
	SetRegistryKey(L"ChildProc");
	CChildProcDlg * dlg = new CChildProcDlg();
	m_pMainWnd = dlg;
	dlg->Create(IDD_CHILDPROC_DIALOG);
	dlg->ShowWindow(SW_SHOW);
	MSG msg;
	BOOL ret;
	while ((ret = GetMessage(&msg, nullptr, 0, 0)) != 0) {
		if (ret == -1)
			continue;
		TranslateMessage(&msg);
		DispatchMessage(&msg);
		if (msg.message == WM_APP + 1) {
			AfxMessageBox(L"Gatcha!");
			dlg->DestroyWindow();
			return FALSE;
		}
	}
	return (BOOL)msg.wParam;
}

PostThreadMessageDemo.cpp

#include "pch.h"
#include "framework.h"
#include "WndMsgComm.h"
#include "WndMsgCommDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

BEGIN_MESSAGE_MAP(CPostThreadMessageDemo, CWinApp)
	ON_COMMAND(ID_HELP, &CWinApp::OnHelp)
END_MESSAGE_MAP()

CPostThreadMessageDemo::CPostThreadMessageDemo()
{
}

CPostThreadMessageDemo theApp;

BOOL CPostThreadMessageDemo::InitInstance()
{
	CWinApp::InitInstance();
	SetRegistryKey(L"WndMsgComm");
	wchar_t path[] = L"C:\\Users\\b05l5008\\source\\repos\\WndMsgComm\\x64\\Debug\\ChildProc.exe";
	STARTUPINFO si;
	::GetStartupInfo(&si);
	if (!::CreateProcess(NULL, path, NULL, NULL, FALSE, NULL, NULL, NULL, &si, &m_pi)) {
		AfxMessageBox(L"CreateProcess failed");
		return FALSE;
	}
	CWndMsgCommDlg dlg;
	m_pMainWnd = &dlg;
	INT_PTR nResponse = dlg.DoModal();
	if (nResponse == IDOK) {
		BOOL ret = ::PostThreadMessage(m_pi.dwThreadId, WM_APP + 1, 0, 0);
		if (!ret) {
			AfxMessageBox(L"PostThreadMessage failed");
		}
	}
	else if (nResponse == IDCANCEL) {
	}
	else if (nResponse == -1) {
	}
	return FALSE;
}

BOOL CPostThreadMessageDemo::ExitInstance()
{
	CloseHandle(m_pi.hThread);
	CloseHandle(m_pi.hProcess);
	return TRUE;
}