Page 42 - DCAP408_WEB_PROGRAMMING
P. 42
Windows Programming
Notes while (GetMessage(&msg, NULL, 0, 0) > 0)
{
Functions are requisite to send the message onto the WndProc function.
First we make use of the TranslateMessage function. The translate message function translates
virtual-key messages into character messages which is required. This function takes one
parameter, being the MSG variable containing the message obtained.
TranslateMessage(&msg);
The next function we are required to use is the DispatchMessage function. This sends the message
via the window procedure (WndProc). It also takes one MSGparameter.
DispatchMessage(&msg);
}
Thus we used the PostQuitMessage function and passed the value of 0. This could have been a
dissimilar value we had passed so we cannot just return 0 as normal. We return the msg.wParam
value which is the return code passed onto the PostQuitMessage function.
return (int)msg.wParam;
You should now be able to develop simple windows messages. If you execute the program, you
will observe that the window will stay on the screen until you close the window. This will
demolish the window and shut the program competently.
Task Make distinction between LPMSG lpMsg and HWND hwnd.
Self Assessment
Fill in the blanks:
7. Message loop is utilized to catch messages and pass them onto our ......................... function.
8. ......................... is used to state what window the message must be recovered for.
9. When the ......................... function is called, the function halts until a message is obtained.
3.5 Creating a New Window Class
The WNDLCLASS and the WNDCLASSEX classes are utilized to initialize the application
window class. To exhibit a window, that is, to provide the user an object to work with, you must
generate a window object. This window is the object the user utilizes to interrelate with the
computer.
To create a window, you can call either the CreateWindow() or the CreateWindowEx()function.
You can just call this function and state its arguments after you have registered the window class.
Example: Here is an example:
INT WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
36 LOVELY PROFESSIONAL UNIVERSITY
