WIN32 对话框抛出异常 [英] WIN32 Dialogue Box Throws exception
问题描述
我正在尝试使用 Microsoft 文档学习 win32 api.我已经到了第 4 章，我似乎遇到了一个我正在努力调试的问题.about按钮触发的对话框抛出异常:
I am trying to learn the win32 api using the Microsoft documentation. I have gotten to chapter 4, and I seem to have run into an issue that I am struggling to debug. The dialogue box triggered by the about button throws an exception:
在practice.exe 0x773BDCFF (ntdll.dll) 处抛出异常.exe: 0xC0000005: 访问冲突读取位置0x00905A4C.
Exception thrown at 0x773BDCFF (ntdll.dll) in practice.exe: 0xC0000005: Access violation reading location 0x00905A4C.
以下是 WndProc 和 About 回调的声明:
Here is the declaration of the WndProc and About callbacks:
static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
static INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam);
以下是实现 WndProc 和 About 回调的代码:
Here is the code for the implementation of the WndProc and About callbacks:
LRESULT CALLBACK App::WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
App* pApp;
if (message == WM_CREATE)
{
LPCREATESTRUCT pcs = (LPCREATESTRUCT)lParam;
pApp = (App*)pcs->lpCreateParams;
::SetWindowLongPtrW(hWnd, GWLP_USERDATA, PtrToUlong(pApp));
return TRUE;
}
else
{
pApp = reinterpret_cast<App*>(static_cast<LONG_PTR>(::GetWindowLongPtrW(hWnd, GWLP_USERDATA)));
if (!pApp)
return DefWindowProc(hWnd, message, wParam, lParam);
}
int wmld, wmEvent;
PAINTSTRUCT ps;
HDC hdc;
switch (message)
{
case WM_COMMAND:
{
int wmId = LOWORD(wParam);
// Parse the menu selections:
switch (wmId)
{
case IDM_ABOUT:
DialogBox(pApp->getInstance(), MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, pApp->About);
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
// TODO: Add any drawing code that uses hdc here...
EndPaint(hWnd, &ps);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
// Message handler for about box.
INT_PTR CALLBACK App::About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
UNREFERENCED_PARAMETER(lParam);
switch (message)
{
case WM_INITDIALOG:
return (INT_PTR)TRUE;
case WM_COMMAND:
if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
{
EndDialog(hDlg, LOWORD(wParam));
return (INT_PTR)TRUE;
}
break;
}
return (INT_PTR)FALSE;
我希望错误在这些片段中.如果没有，我很乐意提供更多代码.我做了研究，我真的不知道问题是什么.我知道 about 函数的回调必须是静态的，我相信它是.除此之外，我不知道什么会导致它抛出异常.感谢您为我提供的任何帮助.
I hope the error is within these snippets. If not, I would be happy to provide more code. I have done research, and I truly have very little idea what the problem is. I know that the callback for the about function must be static, which I believe it is. Apart from that, I don't know what would cause it to throw an exception. Thank you for any help you can give me.
推荐答案
无法使用您提供的代码重现此问题.以下是基于您的代码片段的示例，它对我有用.可以参考.
Fail to reproduce this issue using your presented code. The following is an example based on your code piece and it works for me. You can refer to.
App.h
class App
{
public:
App(HINSTANCE hInstance, CONST WCHAR* clsName);
private:
static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
static INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam);
ATOM MyRegisterClass(HINSTANCE hInstance, CONST WCHAR* clsName);
};
应用程序.cpp
#include "App.h"
App::App(HINSTANCE hInstance, CONST WCHAR* clsName)
{
App::MyRegisterClass(hInstance, clsName);
}
ATOM App::MyRegisterClass(HINSTANCE hInstance, CONST WCHAR* clsName)
{
WNDCLASSEXW wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = App::WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_DIALOGBOXEXCEPTION));
wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wcex.lpszMenuName = MAKEINTRESOURCEW(IDC_DIALOGBOXEXCEPTION);
wcex.lpszClassName = clsName;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
return RegisterClassExW(&wcex);
}
LRESULT CALLBACK App::WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
App* pApp;
if (message == WM_CREATE)
{
LPCREATESTRUCT pcs = (LPCREATESTRUCT)lParam;
pApp = (App*)pcs->lpCreateParams;
::SetWindowLongPtrW(hWnd, GWLP_USERDATA, (LONG_PTR)pApp);
return TRUE;
}
else
{
pApp = reinterpret_cast<App*>(static_cast<LONG_PTR>(::GetWindowLongPtrW(hWnd, GWLP_USERDATA)));
if (!pApp)
return DefWindowProc(hWnd, message, wParam, lParam);
}
switch (message)
{
case WM_COMMAND:
{
int wmId = LOWORD(wParam);
// Parse the menu selections:
switch (wmId)
{
case IDM_ABOUT:
DialogBox(NULL, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, pApp->About);
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
// TODO: Add any drawing code that uses hdc here...
EndPaint(hWnd, &ps);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
// Message handler for about box.
INT_PTR CALLBACK App::About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
UNREFERENCED_PARAMETER(lParam);
switch (message)
{
case WM_INITDIALOG:
return (INT_PTR)TRUE;
case WM_COMMAND:
if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
{
EndDialog(hDlg, LOWORD(wParam));
return (INT_PTR)TRUE;
}
break;
}
return (INT_PTR)FALSE;
}
创建主窗口:
App pApp = App(hInst, szWindowClass);
HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, &pApp);
if (!hWnd)
{
return FALSE;
}
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
这篇关于WIN32 对话框抛出异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
