'OPENFILENAME': undeclared identifier - c++

Question

I'm learning Windows programming (API). When I want to create Open File dialog, first I create structure declaration:
OPENFILENAME ofn;
But I get error:
error C2065: 'OPENFILENAME': undeclared identifier
Full code:
#include "stdafx.h" // <---- included windows.h
#include "Win32_Iczelion_ofn.h"
#define MAX_LOADSTRING 100
// Global Variables:
HINSTANCE hInst; // current instance
TCHAR szTitle[MAX_LOADSTRING]; // The title bar text
TCHAR szWindowClass[MAX_LOADSTRING]; // the main window class name
// Forward declarations of functions included in this code module:
ATOM MyRegisterClass(HINSTANCE hInstance);
BOOL InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK About(HWND, UINT, WPARAM, LPARAM);
int APIENTRY _tWinMain(_In_ HINSTANCE hInstance,
_In_opt_ HINSTANCE hPrevInstance,
_In_ LPTSTR lpCmdLine,
_In_ int nCmdShow)
{
UNREFERENCED_PARAMETER(hPrevInstance);
UNREFERENCED_PARAMETER(lpCmdLine);
// TODO: Place code here.
MSG msg;
HACCEL hAccelTable;
// Initialize global strings
LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
LoadString(hInstance, IDC_WIN32_ICZELION_OFN, szWindowClass, MAX_LOADSTRING);
MyRegisterClass(hInstance);
// Perform application initialization:
if (!InitInstance (hInstance, nCmdShow))
{
return FALSE;
}
hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_WIN32_ICZELION_OFN));
// Main message loop:
while (GetMessage(&msg, NULL, 0, 0))
{
if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
return (int) msg.wParam;
}
ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEX wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_WIN32_ICZELION_OFN));
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = MAKEINTRESOURCE(IDC_WIN32_ICZELION_OFN);
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
return RegisterClassEx(&wcex);
}
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
HWND hWnd;
OPENFILENAME ofn; // <---------- ERROR HERE ----------
hInst = hInstance; // Store instance handle in our global variable
hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
ofn.lStructSize = sizeof (ofn);
ofn.hwndOwner = g_hWindow;
ofn.hInstance = GetModuleHandle(NULL);
ofn.lpstrFile = szFile;
ofn.nFilterIndex = 0;
ofn.nMaxFile = 256;
ofn.lpstrInitialDir = NULL;
ofn.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;
GetOpenFileName(&ofn);
if (!hWnd)
{
return FALSE;
}
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
return TRUE;
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
int wmId, wmEvent;
PAINTSTRUCT ps;
HDC hdc;
switch (message)
{
case WM_COMMAND:
wmId = LOWORD(wParam);
wmEvent = HIWORD(wParam);
// Parse the menu selections:
switch (wmId)
{
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
I search on google but still not fully resolved.
Anyone please help me explain that errors , and figure out step by step to create the Open File dialog, (example for me).
I'm newbie so plz help me my stupid question !!!

Answer 1

Did you add
#include <Commdlg.h>
Error: undeclared identifier may because you don't include needed header file.

Answer 2

In Visual Studio 2017,I had meet the same problem.
If you have a header file named "stdafx.h" ,please cut #include <Commdlg.h> into "stdafx.h"