The usual, whats wrong here?

Sup friends,

MessageBox(NULL, "X = " + xPos + "\nY = " + yPos, "Mouse's Area", MB_OK);}
}


Code tags would be nice.

You can't just throw string literals and ints and plus signs together like that in C++.

Thanks for your post but I've never seen code like that before so as you can see I don't understand it, I will make an effort to understand your code but could you please tell me what this line does exactly -

int xPos = HIWORD(lParam);
int yPos = LOWORD(lParam);

Along with that I have an issue with the following code -

#include <windows.h>

using namespace std;

const char *ClsName = "BasicApp";
const char *WndName = "A Simple Window";

LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg,
WPARAM wParam, LPARAM lParam);

INT WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
MSG Msg;
HWND hWnd;
WNDCLASSEX WndClsEx;

// Create the application window
WndClsEx.cbSize = sizeof(WNDCLASSEX);
WndClsEx.style = CS_HREDRAW | CS_VREDRAW;
WndClsEx.lpfnWndProc = WndProc;
WndClsEx.cbClsExtra = 0;
WndClsEx.cbWndExtra = 0;
WndClsEx.hIcon = LoadIcon(NULL, IDI_APPLICATION);
WndClsEx.hCursor = LoadCursor(NULL, IDC_ARROW);
WndClsEx.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
WndClsEx.lpszMenuName = NULL;
WndClsEx.lpszClassName = ClsName;
WndClsEx.hInstance = hInstance;
WndClsEx.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

// Register the application
RegisterClassEx(&WndClsEx);

// Create the window object
hWnd = CreateWindow(ClsName,
WndName,
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL);

// Find out if the window was created
if( !hWnd ) // If the window was not created,
return 0; // stop the application

// Display the window to the user
ShowWindow(hWnd, SW_SHOWNORMAL);
UpdateWindow(hWnd);

// Decode and treat the messages
// as long as the application is running
while( GetMessage(&Msg, NULL, 0, 0) )
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}

return Msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{

if (Msg==WM_LBUTTONDOWN) LoadCursorFromFile("test.cur");
else if (Msg==WM_DESTROY) PostQuitMessage(WM_QUIT);
else return DefWindowProc(hWnd, Msg, wParam, lParam);
return 0;
}

All it does is start the program up and when I left click nothing happens(and yeah I did make sure the file was in the same folder and I also made sure it had a .cur extension).

Thanks.

Actually use ostringstream so:

std::ostringstream oss;
oss << "X = " << xPos << "\r\nY = " << yPos;
MessageBox( NULL, oss.str().c_str(), "Mouse's Area", MB_OK );

If you are using CString anyway in your project then you can alternatively do

CString msg;
msg.Format( "X = %d\r\nY=%d", xPos, yPos );
MessageBox( NULL, msg, "Mouse's Area", MB_OK ); // or msg.GetString()

As you wish...

lParam is a 32-bit value(under a Win32 environment). In your context it is simply two 16-bit values sandwiched together. In the low-word(LOWORD) it is the x-coordinate relative to the upper-left corner of the client area(your window). In the high-word(HIWORD) it is the y-coordinate.

You use the LOWORD and HIWORD macros to parse those values out of the lParam.

So, if you clicked right in the perfect center of your window, which is, say, 800x600, the lParam would be '400300', logically speaking.

LOWORD will yank out 400 and HIWORD, 300.

Having said that, you should move that code into your WM_LBUTTONDOWN(or whichever button you're using). It doesn't have to be there, but it's good form. The lParam(and wParam) will be different and do different things for each kind of message, so having that code right at the beginning of your WndProc isn't telling you much. It will still work, but there is no context.

1) hInstance is a handle itself, only it's a handle to the program as opposed to something like hWnd, which is a handle to a window of a program.

2) Too vague. There are a bajillion ways to click a 'button' and display a message box. The fact that you're clicking a 'button' is irrelevant(as far as the code is concerned); it's just another message.

I can't think of a simpler or more appropriate way than to call MessageBox(...) from your mouse-button-down events. Don't reinvent the wheel, pally.

3) GetWindowText(...)

1) A handle is just a 32-bit(usually) number that refers to an object. The actual number is of no importance to you. It allows you access to the object's members and suchlike.

2) When you say 'button' are you referring to a push/command button or a mouse button?

3) Nope. I can't write(well, compile) Windows code on this computer. All linux, I'm afraid. There's not all that much going on with GetWindowText(...). Tinker with it. I bet you can find other examples outside of msdn for using it.

1) Nothing, other than one is a handle to the program itself and the other is a handle to a window.

I'm not sure what you're confused about. Umm, if your program has one window and one window only it may seem reasonable to think that the handle to the program and the handle to the program's main window are the same thing, but they are not.

2) What sort of 'action' are you wanting to pop up the messagebox? You can write a program that simply displays a message box without all of the code you have above; it just won't have much functionality.

3) Now we're cookin' with fire. In your CrateWindow(...) calll to create the control you need to change that first 'NULL' to 'hWnd'. That CreateWindow(...) call is creating a child window, whose parent is 'hWnd'. That CreateWindow(...) call needs to know who is going to own this window you're trying to draw. You're using NULL, which, as you've experienced, is probably doing nothing in the case of you're edit control.

When, in WinMain, you use 'NULL' in the call to CreateWindow(...) it's just fine as that implies a 'top-level' or 'main' window; you needn't know the handle to the desktop, which is where the 'main' or 'top-level' window would be drawn...

In that same call you need to modify your 'hInstance.' There are a few ways to do this. I think the simplest would be:

(HINSTANCE)GetWindowLong(hWnd, GWL_HINSTANCE)

GetWindowLong(...) just retrieves info about a particular window, hWnd in this case.

Just cut-n-paste the above where you have 'hInstance' in your CreateWindow(...) call where you're trying to create the edit control.

Note: I'm drawing from memory and have no way to test my 'suggestions', so bear with me. This is all coming out stream-of-consciousness. The API has a few more tricks up its sleeve. If it doesn't work, we'll go elsewhere. We can even 'backdoor' through the lParam, but we'll cross that bridge only if necessary.

Hmm, try adding this:

| WS_VISIBLE

to the right of where it says 'WS_CHILD' in your CreateWindow(...) where you're creating the control. Don't forget those pipes( | ).

Edit: Take that BS_PUSHBUTTON out. I got confused with another post. All apologies...

Take that 'BS_PUSHBUTTON' out. See above edited post.

I'm so stupid. There is no way to process messages in your code, a foundation of the API. How did I not see that!?!

Paste this:

LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_CREATE :
HWND EC = CreateWindow("EDIT",
"Write Stuff Here",
WS_CHILD | WS_VISIBLE,
0,
0,
300,
300,
hWnd,
NULL,
(HINSTANCE)GetWindowLong(hWnd, GWL_HINSTANCE),
NULL);

return 0;

case WM_DESTROY :
PostQuitMessage(0);
return 0;
}

return DefWindowProc(hWnd, Msg, wParam, lParam);
}//This is the end of the program...

I got rid of that 'if' block; worry about that later. We need the window to be drawn before anything else.

I can't believe I forget the message switch. I'm embarrased...

Lol your code confused me so I just did something else and it worked(apparently I forgot about WM_CREATE) -

#include <windows.h>

const char *ClsName = "BasicApp";
const char *WndName = "A Simple Window";

LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg,
WPARAM wParam, LPARAM lParam);

INT WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
MSG Msg;
HWND hWnd;
WNDCLASSEX WndClsEx;

// Create the application window
WndClsEx.cbSize = sizeof(WNDCLASSEX);
WndClsEx.style = CS_HREDRAW | CS_VREDRAW;
WndClsEx.lpfnWndProc = WndProc;
WndClsEx.cbClsExtra = 0;
WndClsEx.cbWndExtra = 0;
WndClsEx.hIcon = LoadIcon(NULL, IDI_APPLICATION);
WndClsEx.hCursor = LoadCursor(NULL, IDC_ARROW);
WndClsEx.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
WndClsEx.lpszMenuName = NULL;
WndClsEx.lpszClassName = ClsName;
WndClsEx.hInstance = hInstance;
WndClsEx.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

// Register the application
RegisterClassEx(&WndClsEx);

// Create the window object
hWnd = CreateWindow(ClsName,
WndName,
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL);

// Find out if the window was created
if( !hWnd ) // If the window was not created,
return 0; // stop the application

// Display the window to the user
ShowWindow(hWnd, SW_SHOWNORMAL);
UpdateWindow(hWnd);

// Decode and treat the messages
// as long as the application is running
while( GetMessage(&Msg, NULL, 0, 0) )
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}

return Msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
HWND EC;

if (Msg==WM_CREATE) {
EC = CreateWindow("EDIT",
"Write stuff here",
WS_CHILD | WS_VISIBLE | ES_MULTILINE,
0,
0,
300,
300,
hWnd,
NULL,
(HINSTANCE)GetWindowLong(hWnd, GWL_HINSTANCE),
NULL);}
else if(Msg==WM_LBUTTONDOWN) {
TCHAR szBuf[80];
GetWindowText(EC, szBuf, 80);
MessageBox(hWnd, szBuf, "You typed -", MB_OK);}
else if (Msg==WM_DESTROY) PostQuitMessage(WM_QUIT);
else return DefWindowProc(hWnd, Msg, wParam, lParam);
return 0;
}

Though I still don't know how to work with buttons. :(

Thanks.

To start with I thank you for your support!

And really, all apologies for not being able to get you working code the first time.
Its alright, it might not seem like it but you taught me a lot and from that I got the code to work :)

The switch-case from previously may not have worked because I used 'message' as the variable to test instead of 'Msg'. Surely your compiler barfed up an 'undeclared identifier' or something similar.
Reply With Quote
Lol, I am not the type who simply copies then pastes, I simply copied the part that seemed relevant :)

Questions -
1) I have some experience with the WM_PAINT message but why do I need to use it right now? What does that code do?
2) Although I have experience I think I should still go over it, so is it OK with you if I ask you to teach me all the basics for painting?

Thanks.

What the heck is wrong with me! -

#include <windows.h>

const char *ClsName = "BasicApp";
const char *WndName = "A Simple Window";

LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg,
WPARAM wParam, LPARAM lParam);

INT WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
MSG Msg;
HWND hWnd;
WNDCLASSEX WndClsEx;

// Create the application window
WndClsEx.cbSize = sizeof(WNDCLASSEX);
WndClsEx.style = CS_HREDRAW | CS_VREDRAW;
WndClsEx.lpfnWndProc = WndProc;
WndClsEx.cbClsExtra = 0;
WndClsEx.cbWndExtra = 0;
WndClsEx.hIcon = LoadIcon(NULL, IDI_APPLICATION);
WndClsEx.hCursor = LoadCursor(NULL, IDC_ARROW);
WndClsEx.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
WndClsEx.lpszMenuName = NULL;
WndClsEx.lpszClassName = ClsName;
WndClsEx.hInstance = hInstance;
WndClsEx.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

// Register the application
RegisterClassEx(&WndClsEx);

// Create the window object
hWnd = CreateWindow(ClsName,
WndName,
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL);

// Find out if the window was created
if( !hWnd ) // If the window was not created,
return 0; // stop the application

// Display the window to the user
ShowWindow(hWnd, SW_SHOWNORMAL);
UpdateWindow(hWnd);

// Decode and treat the messages
// as long as the application is running
while( GetMessage(&Msg, NULL, 0, 0) )
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}

return Msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
HWND EC;

switch (Msg) {

case WM_CREATE :
EC = CreateWindow("EDIT",
"Write stuff here",
WS_CHILD | WS_VISIBLE | ES_MULTILINE | ES_CENTER,
0,
0,
300,
300,
hWnd,
NULL,
(HINSTANCE)GetWindowLong(hWnd, GWL_HINSTANCE),
NULL);
break;

case WM_LBUTTONDOWN :
TCHAR szBuf[80];
GetWindowText(EC, szBuf, 80);
MessageBox(hWnd, szBuf, "You typed -", MB_OK);
break;

case WM_DESTROY :
PostQuitMessage(WM_QUIT);
break;

}

return DefWindowProc(hWnd, Msg, wParam, lParam);
}
For some reason I forgot that the main idea doesn't work; when I do left click on the window the messagebox comes up but has nothing written in it, what's wrong?

Bam. That's an entire program.
I guess that there is still an mis-understanding, I just want to know how to detect when a user clicks a button, I don't really care about the message-box itself but like I said I just want to know how to tell if the user clicks a button and thats it(by the way you just used a Linux MessageBox :)).

You can certainly ask me questions, but it would take a prohibitive amount of time to go over every last detail of drawing and painting. And it's not like I've 'mastered' Win32 API programming anyway.
Can you really blame me for thinking you're very good(complement :))? By the way I said the basics is what I want/need to learn.

questions -
1) Apart from the ones I've already asked, how do you work with sound? May I have an example in which a simple file called file.(extension) is played from the program's main directory?

Thanks (I really appreciate it)!

The following code doesn't play sound(defined under the WM_RBUTTONDOWN message) and doesn't display the text in the message box eighter(WM_LBUTTONDOWN) -

#include <windows>

const char *ClsName = "BasicApp";
const char *WndName = "A Simple Window";

LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg,
WPARAM wParam, LPARAM lParam);

INT WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
MSG Msg;
HWND hWnd;
WNDCLASSEX WndClsEx;

// Create the application window
WndClsEx.cbSize = sizeof(WNDCLASSEX);
WndClsEx.style = CS_HREDRAW | CS_VREDRAW;
WndClsEx.lpfnWndProc = WndProc;
WndClsEx.cbClsExtra = 0;
WndClsEx.cbWndExtra = 0;
WndClsEx.hIcon = LoadIcon(NULL, IDI_APPLICATION);
WndClsEx.hCursor = LoadCursor(NULL, IDC_ARROW);
WndClsEx.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
WndClsEx.lpszMenuName = NULL;
WndClsEx.lpszClassName = ClsName;
WndClsEx.hInstance = hInstance;
WndClsEx.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

// Register the application
RegisterClassEx(&WndClsEx);

// Create the window object
hWnd = CreateWindow(ClsName,
WndName,
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL);

// Find out if the window was created
if( !hWnd ) // If the window was not created,
return 0; // stop the application

// Display the window to the user
ShowWindow(hWnd, SW_SHOWNORMAL);
UpdateWindow(hWnd);

// Decode and treat the messages
// as long as the application is running
while( GetMessage(&Msg, NULL, 0, 0) )
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}

return Msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
HWND EC;

switch (Msg) {

case WM_CREATE :
EC = CreateWindow("EDIT",
"Write stuff here",
WS_CHILD | WS_VISIBLE | ES_MULTILINE | ES_CENTER,
0,
0,
300,
300,
hWnd,
NULL,
(HINSTANCE)GetWindowLong(hWnd, GWL_HINSTANCE),
NULL);
break;

case WM_LBUTTONDOWN :
char szBuf[80];
GetWindowText(EC, szBuf, 80);
MessageBox(hWnd, szBuf, "You typed -", MB_OK);
break;

case WM_RBUTTONDOWN :
PlaySound("file.wma", NULL, SND_FILENAME);
break;

case WM_DESTROY :
PostQuitMessage(WM_QUIT);
break;

}

return DefWindowProc(hWnd, Msg, wParam, lParam);
}
When I right click on my program it just makes a beep and that's it. And I'm sure I have given szBuf a value; that's what GetWindowText is doing right?

1) Nothing but the title(its a constant).
2) Doing what?
3) I tried it but it didn't work :(

Thanks.

1) I don't know what to tell you. The GetWindowText function's default behavior is to retrieve the caption from a window unless it's a control, which, in this case, it is. But it's obviously retrieving the caption from your main window.

2) I've only gotten PlaySound(...) in Windows IDEs. 'Got me there, too.

I mean I don't know how to help you with the PlaySound. I've used it only once.

'Don't know about context menus or getting a program into the tray either.

And I'm not entirely sure what you mean in your last question.

Oh, I'm sure there's some way to, but I can't see why you would want to.

Also, try posting in the Win32 API forum. That's what we're talking about, afterall.

Alright, try GetDlgItemText(...) in your WM_LBUTTONDOWN. Supply the handle to the parent window.

You'll also have to define an ID for the control. Somewhere at the top of your code(I usually do this right after my 'includes') put in something like:

#define ID_EDIT 1

You can choose the name and number arbitrarily. The important thing is that they are unique. All caps and underscores are convention, but not enforced.

In your CreateWindow(...) function for the edit control, the ninth(the 'menu' one) parameter needs to read:

(HMENU)ID_EDIT

Of course, if you choose a different name you'll need to reflect that in the CreateWindow(...) call for your edit control.

Doesn't matter.

No way, pally. You are your own best teacher.

I've already told you what to do and where to put it. I haven't told you how to implement the GetDlgItemText(...) because you can find its signature online pretty easily. It's a simple function, like MessageBox(...)

Also, I see no calls to CreateWindowEx(...). If that were the case there's, like, one extra parameter.

Anyway, look up the signature to CreateWindow(...) and look for the parameter that says something to the effect of hMenu. That is where you will put what I listed previously in your call to CreateWindow(...) for the edit control.

You haven't supplied an hWnd parameter. Check GetDlgItemText's signature on MSDN again.

Also, use the name of the named constant and not the value. Either will work, but it's good practice to use the name as it is more meaningful than '113'.