c++ - 如何确定用户单击 "Cancel"时 FindText 对话框已关闭

Question

此代码生成简单的 FindText 对话窗口，当用户单击右上角的 X 窗口关闭按钮时，WM_CLOSE 消息将发送到 Hook 程序，但当单击“取消”按钮时，不会生成任何消息来指示该窗口不再存在。

#include <windows.h>
#include <iostream>
#include <iomanip>

UINT_PTR CALLBACK FRHookProc(HWND hdlg, UINT uiMsg, WPARAM /*wParam*/, LPARAM /*lParam*/) {
  switch (uiMsg) {
    case WM_INITDIALOG: {
      ShowWindow(hdlg, SW_SHOW);
      break;
    }
  }
  using namespace std;
  if (uiMsg == WM_CLOSE) cout << "FindTextW window has been closed";
  return 0;
}

LRESULT CALLBACK MyWndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
  return DefWindowProcW(hWnd, Msg, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, LPTSTR, int /* nCmdShow*/) {
  using namespace std;

  WNDCLASSEXW wc;
  wc.cbSize = sizeof(WNDCLASSEXW);
  wc.style = CS_HREDRAW | CS_VREDRAW;
  wc.lpfnWndProc = &MyWndProc;
  wc.cbClsExtra = 0;
  wc.cbWndExtra = sizeof(PVOID);
  wc.hInstance = hInstance;
  wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
  wc.hIconSm = NULL;
  wc.hCursor = LoadCursor(NULL, IDC_ARROW);
  wc.hbrBackground = reinterpret_cast<HBRUSH>(COLOR_BACKGROUND);
  wc.lpszMenuName = L"MainMenu";
  wc.lpszClassName = L"window";
  ATOM class_atom = RegisterClassExW(&wc);

  HWND hWnd = CreateWindowExW(
    0,
    reinterpret_cast<LPCWSTR>(class_atom),
    L"window title",
    WS_OVERLAPPEDWINDOW | WS_VISIBLE | WS_CLIPCHILDREN | WS_CLIPCHILDREN | WS_THICKFRAME,
    CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
    NULL,
    NULL,
    hInstance,
    NULL
  );

  WCHAR szFindWhat[MAX_PATH] = {0};

  FINDREPLACEW fr;
  ZeroMemory(&fr, sizeof(fr));
  fr.lStructSize = sizeof(fr);
  fr.hwndOwner = hWnd;
  fr.lpstrFindWhat = szFindWhat;
  fr.lpfnHook = FRHookProc;
  fr.wFindWhatLen = MAX_PATH;
  fr.Flags = FR_ENABLEHOOK;
  /*HWND hdlg =*/ FindTextW(&fr);

  MSG msg;
  for (;;) {
    GetMessageW(&msg, 0, 0, 0);
    TranslateMessage(&msg);
    DispatchMessageW(&msg);
  }
  return 0;
}

Answer 1

Read the documentation更仔细。您采用了完全错误的方法来检测正在关闭的对话窗口。

FindText function :

Before calling FindText, you must call the RegisterWindowMessage function to get the identifier for the FINDMSGSTRING message. The dialog box procedure uses this identifier to send messages when the user clicks the Find Next button, or when the dialog box is closing.

FINDMSGSTRING message :

A Find or Replace dialog box sends the FINDMSGSTRING registered message to the window procedure of its owner window when the user clicks the Find Next, Replace, or Replace All button, or closes the dialog box.

...

You must specify the FINDMSGSTRING constant in a call to the RegisterWindowMessage function to get the identifier for the message sent by the dialog box.

When you create the dialog box, use the hwndOwner member of the FINDREPLACE structure to identify the window to receive FINDMSGSTRING messages.

...

The Flags member of the FINDREPLACE structure includes one of the following flags to indicate the event that caused the message.

FR_DIALOGTERM (0x00000040) The dialog box is closing. After the owner window processes this message, a handle to the dialog box is no longer valid.

所以，话虽如此，试试这个:

#include <windows.h>
#include <iostream>
#include <iomanip>

static const UINT uFindMsgString = RegisterWindowMessageW(L"commdlg_FindReplace");

LRESULT CALLBACK MyWndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
  if ((Msg == uFindMsgString) && (Msg != 0))
  {
    FINDREPLACE *fr = reinterpret_cast<FINDREPLACE*>(lParam);
    if (fr->flags & FR_DIALOGTERM)
    {
      std::cout << "FindTextW window has been closed";
      PostQuitMessage(0);
    }

    // process other dialog notifications as needed...

    return 0;
  }

  return DefWindowProcW(hWnd, Msg, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, LPTSTR, int /* nCmdShow*/)
{
  WNDCLASSEXW wc = {0};
  wc.cbSize = sizeof(WNDCLASSEXW);
  wc.style = CS_HREDRAW | CS_VREDRAW;
  wc.lpfnWndProc = &MyWndProc;
  wc.cbClsExtra = 0;
  wc.cbWndExtra = sizeof(PVOID);
  wc.hInstance = hInstance;
  wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
  wc.hIconSm = NULL;
  wc.hCursor = LoadCursor(NULL, IDC_ARROW);
  wc.hbrBackground = reinterpret_cast<HBRUSH>(COLOR_BACKGROUND);
  wc.lpszMenuName = L"MainMenu";
  wc.lpszClassName = L"window";

  ATOM class_atom = RegisterClassExW(&wc);

  HWND hWnd = CreateWindowExW(
    0,
    wc.lpszClassName,
    L"window title",
    WS_OVERLAPPEDWINDOW | WS_VISIBLE | WS_CLIPCHILDREN | WS_CLIPCHILDREN | WS_THICKFRAME,
    CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
    NULL,
    NULL,
    hInstance,
    NULL
  );

  WCHAR szFindWhat[MAX_PATH] = {0};

  FINDREPLACEW fr = {0};
  fr.lStructSize = sizeof(fr);
  fr.hwndOwner = hWnd;
  fr.lpstrFindWhat = szFindWhat;
  fr.wFindWhatLen = MAX_PATH;

  HWND hdlg = FindTextW(&fr);

  MSG msg;
  while (GetMessageW(&msg, 0, 0, 0) > 0)
  {
    if (!IsDialogMessage(hdlg, &msg))
    {
      TranslateMessage(&msg);
      DispatchMessageW(&msg);
    }
  }

  DestroyWindow(hWnd);
  UnregisterClass(wc.lpszClassName, hInstance);

  return 0;
}