我正在做一个简单的文本编辑器win32应用程序，很有趣。我的程序有一个特殊的问题。看来我的程序退出时没有返回零。相反，它返回1385929。当我的主GUI窗口被破坏时，我使用PostQuitMessage( 0 )，但似乎不是在主函数的中返回的东西message.wParam。到目前为止，这是我的代码，
#define WIDTH 500
#define HEIGHT 400
#define EDIT_ID 10
LRESULT CALLBACK windowProc( HWND window, UINT message, WPARAM wParam, LPARAM lParam )
{
static HDC deviceContext = INVALID_HANDLE_VALUE;
static HWND editControl = INVALID_HANDLE_VALUE;
switch ( message )
{
case WM_CREATE :
deviceContext = GetDC( window );
if ( !deviceContext )
{
showWindowsError( "Creating Device Context", FALSE );
DestroyWindow( window );
}
editControl = CreateWindow(
"EDIT",
NULL,
WS_CHILD | WS_VISIBLE | WS_VSCROLL | ES_LEFT |
ES_MULTILINE | ES_AUTOVSCROLL | ES_NOHIDESEL,
0,
0,
0,
0,
window,
( HMENU )EDIT_ID,
( HINSTANCE )GetWindowLong( window, GWL_HINSTANCE ),
NULL
);
if ( !editControl )
{
showWindowsError( "Creating Edit Control", TRUE );
DestroyWindow( window );
}
return 0;
break;
case WM_COMMAND :
switch ( wParam )
{
case WM_UNDO :
SendMessage( editControl, WM_UNDO, 0, 0 );
break;
case WM_CUT :
SendMessage( editControl, WM_CUT, 0, 0 );
break;
case WM_COPY :
SendMessage( editControl, WM_COPY, 0, 0 );
break;
case WM_PASTE :
SendMessage( editControl, WM_PASTE, 0, 0 );
break;
case WM_CLEAR :
SendMessage( editControl, WM_CLEAR, 0, 0 );
break;
default:
return DefWindowProc( window, message, wParam, lParam );
}
case WM_SIZE :
MoveWindow( editControl, 0, 0, LOWORD( lParam ), HIWORD( lParam ), TRUE );
return 0;
break;
case WM_DESTROY :
ReleaseDC( window, deviceContext );
DestroyWindow( editControl );
PostQuitMessage( 0 );
return 0;
break;
}
return DefWindowProc( window, message, wParam, lParam );
}
int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR CmdArgs, int nCmdShow )
{
WNDCLASSEX windowClass = { 0 };
HWND window = INVALID_HANDLE_VALUE;
MSG message = { 0 };
HBRUSH windowColor = CreateSolidBrush( GetSysColor( COLOR_WINDOW ) );
windowClass.cbSize = sizeof( windowClass );
windowClass.style = CS_HREDRAW | CS_VREDRAW;
windowClass.lpfnWndProc = windowProc;
windowClass.hInstance = hInstance;
windowClass.hCursor = LoadCursor( NULL, IDC_ARROW );
windowClass.hIcon = LoadIcon( NULL, IDI_APPLICATION );
windowClass.hbrBackground = windowColor;
windowClass.lpszClassName = "TextEditorWindow";
if ( !RegisterClassEx( &windowClass ) )
{
DeleteObject( windowColor );
showWindowsError( "Registering Windows Class", TRUE );
}
window = CreateWindow(
"TextEditorWindow",
"Text Editor",
WS_OVERLAPPED | WS_SYSMENU | WS_CAPTION | WS_THICKFRAME | WS_MINIMIZEBOX | WS_MAXIMIZEBOX,
CW_USEDEFAULT,
CW_USEDEFAULT,
WIDTH,
HEIGHT,
NULL,
NULL,
hInstance,
NULL
);
if ( !window )
{
DeleteObject( windowColor );
showWindowsError( "Creating GUI", TRUE );
}
ShowWindow( window, SW_SHOW );
UpdateWindow( window );
do
{
TranslateMessage( &message );
DispatchMessage( &message );
} while ( GetMessage( &message, window, 0, 0 ) > 0 );
DeleteObject( windowColor );
return message.wParam;
}
您的调用GetMessage()将第二个参数设置为窗口的HWND，这将接收到的消息仅限制为发送到该窗口的消息-请参阅API函数的文档。
WM_QUIT另一方面，消息是发送到运行消息泵的线程的消息，没有任何特定的窗口。由于存在该过滤器，因此您不会收到它，message.wParam也永远不会将其设置为0。
但是，为什么循环结束并且程序仍然关闭？由于HWNDinwindow在窗口关闭后变为in无效，因此GetMessage()以错误结束并返回-1。
此外，您当前正在调用TranslateMessage()，DispatchMessage()并且message在第一次迭代之前用正确的数据填充之前。循环应该是这样的：
while ( GetMessage( &message, NULL, 0, 0 ) > 0 )
{
TranslateMessage( &message );
DispatchMessage( &message );
}
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