I just want to click the button and change the text of the button, however, I would get the WM_CLOSE message, it confused me.
const wchar_t *g_szClassName = L"myWindowClass";
HWND hwnd;
HWND hButtonLine;
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_CREATE:
{
hButtonLine = CreateWindowW(L"BUTTON", L"change title", WS_VISIBLE | WS_CHILD, 20, 50, 150, 25, hwnd, (HMENU)ID_CHANGE_TITLE, NULL, NULL);
break;
}
case WM_COMMAND:
switch (HIWORD(wParam)) {
case BN_CLICKED:
SetWindowText(hButtonLine, L"You clicked the button");
break;
default:
break;
}
case WM_CLOSE:
if (MessageBox(hwnd, L"Really quit?", L"My application", MB_OKCANCEL) == IDOK)
{
DestroyWindow(hwnd);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
MSG Msg;
//Step 1: Registering the Window Class
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&wc))
{
MessageBox(NULL, L"Window Registration Failed!", L"Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE,
g_szClassName,
L"Happy Today",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 450, 250,
NULL, NULL, hInstance, NULL);
if(hwnd == NULL)
{
MessageBox(NULL, L"Window Creation Failed!", L"Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
oh, thks #RaymondChen, I missed the break here.
Related
I’m new to WinAPI development.
The main window contains three Edit controls.When clicking with the left mouse button on Edit1, the message "Edit1 choosed" is to be displayed. When you click on Edit2, it is supposed to display the message "Edit2 choosed". Similarly, when you click on Edit3, the message "Edit3 choosed" should be displayed. I tried using various combinations of WM_LBUTTONDOWN and WM_SETFOCUS, unfortunately the program does not work. Could someone please help me?
#include <windows.h>
#define Edit1 501
#define Edit2 502
#define Edit3 503
HWND TextBox1, TextBox2, TextBox3;
HFONT HF = CreateFont (30, 0, 00, 00, FW_DONTCARE, FALSE, FALSE, FALSE, ANSI_CHARSET,
OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS, DEFAULT_QUALITY, DEFAULT_PITCH | FF_SWISS, "Arial");
LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam) {
switch(Message)
{
case WM_SETFOCUS:
if(wParam == Edit1)
{
MessageBox(NULL, "Edit1 choosed","Edit1",MB_ICONEXCLAMATION|MB_OK);
}
break;
if(wParam == Edit2)
{
MessageBox(NULL, "Edit2 choosed","Edit2",MB_ICONEXCLAMATION|MB_OK);
}
break;
if(wParam == Edit3)
{
MessageBox(NULL, "Edit3 choosed","Edit3",MB_ICONEXCLAMATION|MB_OK);
}
break;
case WM_CREATE:
{
TextBox1 = CreateWindowEx( WS_EX_CLIENTEDGE, "EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER | ES_RIGHT,
30, 70, 190, 40, hwnd, (HMENU)Edit1, GetModuleHandle(NULL), NULL);
SendMessage(TextBox1, WM_SETFONT,( WPARAM ) HF, 0 );
TextBox2 = CreateWindowEx( WS_EX_CLIENTEDGE, "EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER | ES_RIGHT,
30, 130, 190, 40, hwnd, (HMENU)Edit2, GetModuleHandle(NULL), NULL);
SendMessage(TextBox2, WM_SETFONT,( WPARAM ) HF, 0 );
TextBox3 = CreateWindowEx( WS_EX_CLIENTEDGE, "EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER | ES_RIGHT,
30, 190, 190, 40, hwnd, (HMENU)Edit3, GetModuleHandle(NULL), NULL);
SendMessage(TextBox3, WM_SETFONT,( WPARAM ) HF, 0 );
break;
}
case WM_DESTROY:
{
PostQuitMessage(0);
break;
}
default:
return DefWindowProc(hwnd, Message, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
MSG msg;
memset(&wc,0,sizeof(wc));
wc.cbSize = sizeof(WNDCLASSEX);
wc.lpfnWndProc = WndProc;
wc.hInstance = hInstance;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszClassName = "WindowClass";
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&wc)) {
MessageBox(NULL, "Window Registration Failed!","Error!",MB_ICONEXCLAMATION|MB_OK);
return 0;
}
hwnd = CreateWindowEx(WS_EX_CLIENTEDGE,"WindowClass","Caption",WS_VISIBLE|WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 640, 480, NULL,NULL,hInstance,NULL);
if(hwnd == NULL) {
MessageBox(NULL, "Window Creation Failed!","Error!",MB_ICONEXCLAMATION|MB_OK);
return 0;
}
while(GetMessage(&msg, NULL, 0, 0) > 0)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
the "break" in the message loop under WM_SETFOCUS is always executed. So the program never reaches the point of the second edit control. Move the break to before the closing "}" and retry.
{
MessageBox(NULL, "Edit1 choosed","Edit1",MB_ICONEXCLAMATION|MB_OK);
break;
}
Furthermore, consider using 'else if'.
A GUI app I'm writing does send a keydown event to another window, a cmd.exe.
PostMessage(hwnd, WM_KEYDOWN, VK_RETURN, 0);
The event is sent just fine when it's done on events like WM_CREATE, WM_KEYUP, etc (a new line appears in cmd.exe).
Then I setup a global hotkey with RegisterHotKey. In a WM_HOTKEY handler I successfully receive key presses but PostMessage has no effect anymore.
How to fix that?
Full example, minified as possible:
#include <iostream>
#include <Windows.h>
using namespace std;
const char g_szClassName[] = "myWindowClass";
BOOL CALLBACK enumWindows(HWND hwnd, LPARAM lParam) {
char winTitle[1024*10];
GetWindowText(hwnd, winTitle, sizeof(winTitle));
if (strstr(winTitle, "cmd.exe") != NULL) {
cout << "Sending a message to window " << hwnd << ": " << winTitle << endl;
PostMessage(hwnd, WM_KEYDOWN, VK_RETURN, 0);
}
return TRUE;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
switch(msg) {
case WM_CREATE:
// register hotkey ctrl+alt+s
RegisterHotKey(hwnd, 100, MOD_ALT | MOD_CONTROL, 'S');
break;
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
EnumWindows(enumWindows, 0);
PostQuitMessage(0);
break;
case WM_HOTKEY:
// hotkey ctrl+alt+s fired
EnumWindows(enumWindows, 0);
break;
case WM_KEYUP:
EnumWindows(enumWindows, 0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
// just init stuff, do not waste your time
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
RegisterClassEx(&wc);
hwnd = CreateWindowEx(WS_EX_CLIENTEDGE, g_szClassName, "Test", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 240, 120, NULL, NULL, hInstance, NULL);
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
while(GetMessage(&Msg, NULL, 0, 0) > 0) {
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
Windows 7 64-bit
Raymond Chen has documented why this doesn't work the way you expect (PostMessage IS working just fine, but the response of the other window depends on actual keyboard state, just as I surmised in my comment). See his blog post:
You can't simulate keyboard input with PostMessage
The following program works on Windows 7 but not on Windows 7 Embedded Standard Service Pack 1. It does not prevent the shutdown (e.g. shutdown /r /t 0) from happening.
This is a similar question as the one which is linked as duplicate. But that question has the accepted answer of "it does not work". I also provide sourcecode to a working solution in Windows 7 which just needs some adjustment for Windows Embedded.
Any ides how to get it working on Embedded? Or at least a hint where the Windows Docu points that difference out?
#include <windows.h>
#include <stdio.h>
const char g_szClassName[] = "myWindowClass";
// Step 6: the Window Procedure
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_QUERYENDSESSION:
OutputDebugStr("Got WM_QUERYENDSESSION message\n");
char buf[1024];
sprintf(buf, "Callback %d %d\n", wParam, lParam);
OutputDebugStr(buf);
return FALSE; // FALSE should prevent reboot
break;
case WM_ENDSESSION:
OutputDebugStr("Got WM_ENDSESSION message\n");
Sleep(5000); // Should never get here!
break;
case WM_CLOSE:
OutputDebugStr("Got WM_CLOSE message\n");
DestroyWindow(hwnd);
break;
case WM_DESTROY:
OutputDebugStr("Got WM_DESTROY message\n");
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;
//Step 1: Registering the Window Class
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&wc))
{
MessageBox(NULL, "Window Registration Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
// Step 2: Creating the Window
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE,
g_szClassName,
"The title of my window",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 240, 120,
NULL, NULL, hInstance, NULL);
if(hwnd == NULL)
{
MessageBox(NULL, "Window Creation Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
// Step 3: We provide a reason for the shutdown prevention
BOOL ret = ShutdownBlockReasonCreate(hwnd, L"PreventShutdown running which prevents shutdown");
if(ret == FALSE)
{
MessageBox(NULL, "ShutdownBlockReasonCreate Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
// Step 4: We elevate the program to be asked as soon as possible to inhibit shutdown
ret = SetProcessShutdownParameters(0x4FF, SHUTDOWN_NORETRY)
if(ret == FALSE)
{
MessageBox(NULL, "ShutdownBlockReasonCreate Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
OutputDebugStr("Now starting message loop\n");
// Step 5: The Message Loop
while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
We already have a canonical answer for this question, you'll find it here. Seven hundred views and half a year of researching this make this the best known answer, it can't be done.
Keep an eye on your existing question on the MSDN Forums.
I'll close with a few graphical explanations why this kind of feature is not implemented on an embedded operating system:
I am a newbie in win32 API and I'm trying to write an app that will calculate the md5sum of a file selected through the menu or dragged and dropped in the window. I want the window to have 3 columns so that it can display the filename, path and md5sum respectively. Can someone please give me a sample code as to how to make my window look like this?
Also can someone please add the code to create the window as listbox while the menu and drag-drop options are retained?
LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
OPENFILENAME ofn;
char szFileName[MAX_PATH] = "";
ZeroMemory(&ofn, sizeof(ofn));
ofn.lStructSize = sizeof(OPENFILENAME); // SEE NOTE BELOW
ofn.hwndOwner = hwnd;
ofn.lpstrFilter = L"Text Files (*.txt)\0*.txt\0All Files (*.*)\0*.*\0";
wchar_t dest[255];
mbstowcs(dest,szFileName,255);
ofn.lpstrFile = dest;
ofn.nMaxFile = MAX_PATH;
ofn.Flags = OFN_EXPLORER | OFN_FILEMUSTEXIST | OFN_HIDEREADONLY;
ofn.lpstrDefExt = L"txt";
SendDlgItemMessage(hwnd, IDC_LIST, LB_ADDSTRING, 0, (LPARAM)"Hi there!");
if(Message == WM_DROPFILES)
{
HDROP hDropInfo = (HDROP)wParam;
char sItem[MAX_PATH];
for(int i = 0; DragQueryFileA(hDropInfo, i, (LPSTR)sItem, sizeof(sItem)); i++)
{
if(GetFileAttributesA(sItem) &FILE_ATTRIBUTE_DIRECTORY)
{
MessageBox(hwnd, L"Attemt to calculate md5 of a directory!", L"Error",
MB_OK | MB_ICONINFORMATION);
}
else
{
mbstowcs(dest,sItem,260);
LoadFileToGetMD5(hwnd,dest);
}
}
}
switch(Message)
{
case WM_COMMAND:
switch(LOWORD(wParam))
{
case ID_FILE_OPEN:
{
if(GetOpenFileName(&ofn))
{
MessageBox(hwnd, dest, L"Notice",
MB_OK | MB_ICONINFORMATION);
LoadFileToGetMD5(hwnd,dest);
}
else
{
MessageBoxA(hwnd, "File Cannot be opened!", "Error",
MB_OK | MB_ICONINFORMATION);
}
}
break;
case ID_FILE_EXIT:
PostMessageA(hwnd, WM_CLOSE, 0, 0);
break;
case ID_STUFF_ABOUT:
{
DialogBox(GetModuleHandle(NULL),
MAKEINTRESOURCE(IDD_ABOUT), hwnd, AboutDlgProc);
}
break;
}
break;
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProcA(hwnd, Message, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = NULL;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = MAKEINTRESOURCE(ID_MENU);
wchar_t dest[25];
mbstowcs(dest,g_szClassName,25);
wc.lpszClassName = dest;
wc.hIconSm = NULL;
char name[10]="md5sum";
if(!RegisterClassEx(&wc))
{
MessageBoxA(NULL, "Window Registration Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
hwnd = CreateWindowExA(
WS_EX_ACCEPTFILES,
g_szClassName,
"md5sum",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 240, 120,
NULL, NULL ,hInstance, NULL);
if(hwnd == NULL)
{
MessageBoxA(NULL, "Window Creation Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
if(!IsDialogMessage(g_hToolbar, &Msg))
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
}
return Msg.wParam;
}
you should search google for "listview in winapi"
btw,here is a code http://www.win32apicode.com/listview.php
This program works well when the left mouse button is pressed in the window of application, but what i need is that the program also registers when the button is pressed out of the application. I am running under windows 7.
#include <windows.h>
const char g_szClassName[] = "myWindowClass";
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_LBUTTONDOWN:
{
char szFileName[MAX_PATH];
HINSTANCE hInstance = GetModuleHandle(NULL);
GetModuleFileName(hInstance, szFileName, MAX_PATH);
MessageBox(hwnd, szFileName, "This program is:",
MB_OK | MB_ICONINFORMATION);
}
break;
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&wc))
{
MessageBox(NULL, "Window Registration Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE,
g_szClassName,
"The title of my window",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 240, 120,
NULL, NULL, hInstance, NULL);
if(hwnd == NULL)
{
MessageBox(NULL, "Window Creation Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
You can try the Windows Raw Input API, which ignores focus.