How to make a simple Win32 program
Posted: Mon Nov 07, 2011 7:58 pm
After i started programming in unmanaged C++ i have realized how incredibly much the .NET framework has done to make programming simple. Im now going to show you how to make a window in a Win32 program.
This tutorial assumes that you have a basic knowledge of C++.
Lets start with the headers. You need to include <Windows.h> for the window functions, and thats about it. Then, you need your windows main function and your window procedure. I will take you step by step through them.
Next comes the code that sets the info about our window. It sets information such as background color, the window procedure, the icon, the cursor, a menu, and most important; the class name.
There is another way of coding the message loop too, that method waits until it gets a message to process, so your application is never idle (as far as i know). Feel free to use the one you like.
uMsg is the message id/type.
wParam and lParam is additional information for a message.
We have a switch statement to use the right code on the right message. In this tutorial we will handle WM_CREATE (creation) and WM_CLOSE (closing). We will leave the rest to DefWindowProc.
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This tutorial assumes that you have a basic knowledge of C++.
Lets start with the headers. You need to include <Windows.h> for the window functions, and thats about it. Then, you need your windows main function and your window procedure. I will take you step by step through them.
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Okay thats the easy part. Now for the hard part.
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int iCmdShow);
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
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We will need these two variables to store our window class, for retrieving messages and to decide when to quit.int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int iCmdShow) {
WNDCLASS wc;
MSG msg;
BOOL Quit = false;
HWND hWnd = NULL;
Next comes the code that sets the info about our window. It sets information such as background color, the window procedure, the icon, the cursor, a menu, and most important; the class name.
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Then we have to register the class
wc.style = CS_OWNDC;
wc.lpfnWndProc = WndProc; //Window procedure
wc.cbClsExtra = 0; //Extra space (in bytes) for the application
wc.cbWndExtra = 0; //Extra space (in bytes) for each window
wc.hInstance = hInstance; //Instance
wc.hIcon = LoadIcon (NULL, IDI_APPLICATION); //Icon
wc.hCursor = LoadCursor (NULL, IDC_ARROW); //Cursor
wc.hbrBackground = CreateSolidBrush(RGB(123, 123, 123)); //Background
wc.lpszMenuName = NULL; //No menu
wc.lpszClassName = "MyWindow"; //Class nameCode: Select all
Now we have come far enough to create our window, it has been much more work than Dim form = New Form1 hasn't it?
RegisterClass (&wc);Code: Select all
So we have to show our window:
hWnd = CreateWindow (
"MyWindow", "Awesome Window Title", //MyWindow MUST be the same as the lpszClassName ^^
WS_OVERLAPPEDWINDOW, //Window style
0, 0, 600, 300, //x, y, width, height
NULL, NULL, hInstance, NULL); //parent, menu, app instance, ?? lpvoid ??Code: Select all
Now comes our message loop, this catches care of all incoming messages and processes them.
ShowWindow(hWnd, 5);
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When your application is idle, it means that it has no messages to process, so it is free to do any task. while (!Quit)
{
if (PeekMessage (&msg, NULL, 0, 0, PM_REMOVE))
{
if (msg.message == WM_QUIT)
{
Quit = TRUE;
}
else
{
TranslateMessage (&msg);
DispatchMessage (&msg); //An indirect call to the WndProc you defined in wc.lpfnWndProc
}
}
else
{
//Application idle
}
}
There is another way of coding the message loop too, that method waits until it gets a message to process, so your application is never idle (as far as i know). Feel free to use the one you like.
Code: Select all
Finally, we return the result returned from WndProc (wc.lpfnWndProc). 0 for success, and nonzero for fail.
while(!Quit) {
while(GetMessage(&msg, NULL, 0, 0) > 0)
{
if (msg.message == WM_QUIT) { Quit = TRUE; }
TranslateMessage(&msg);
DispatchMessage(&msg); //Indirect call to wc.lpfnWndProc
}
}
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Finally finished you might think, but no. This was just our main window function. Now we need to create our WndProc function. This handles messages for us. return msg.wParam;
}
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hWnd is the window handle. LRESULT CALLBACK WndProc (HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
uMsg is the message id/type.
wParam and lParam is additional information for a message.
We have a switch statement to use the right code on the right message. In this tutorial we will handle WM_CREATE (creation) and WM_CLOSE (closing). We will leave the rest to DefWindowProc.
Code: Select all
Now, finally we come to an end. If you managed to understand all this, I'm impressed. If everything was copy/paste, try again :P case WM_CREATE:
MessageBox(hWnd, "An awesome messagebox", "Title", MB_OK);
return 0;
case WM_CLOSE:
MessageBox(hWnd, "Closing :(", ":'(", MB_OK);
PostQuitMessage(0);
return 0;
default:
return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
}
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