I can't init that combo box!

[Gravedigga]

Hi and thanks for reading this.

I want to initialize a combo box.When I create the dialog, in which the box will be, I send CB_ADDSTRING to the box, but it doesn't works

Here is the code:

theWnd=CreateDialog(hInst,MAKEINTRESOURCE(IDD_PROB
A),NULL,DlgProc);
i=GetLastError();
SendDlgItemMessage(theWnd,IDC_COMBO1,CB_ADDSTRING,
0,(LPARAM) "some text");
ShowWindow(theWnd, SW_SHOW);

I have tried to put the code in the WM_INITDIALOG or WM_CREATE message-handlers of the windows procedure:

BOOL CALLBACK DlgProc(HWND hwndDlg,UINT uMsg,WPARAM wParam,LPARAM lParam)
{
switch(uMsg)	{
case WM_CREATE:
SendDlgItemMessage(hwndDlg,IDC_COMBO1,CB_ADDSTRING,0,(LPARAM) "some text");
break;
case WM_INITDIALOG:
SendDlgItemMessage(hwndDlg,IDC_COMBO1,CB_ADDSTRING,0,(LPARAM) "some text");

....................

If somebody can tell me where the problem is, please tell me!

[Dante Shamest]

Your code seems fine to me (I think). Did you return TRUE when handling WM_INITDIALOG?

[lobo]

Try checking out return value... what styles do you specify for that combobox?

[Gravedigga]

I've created the combo box with a resource editor and the styles that I've specified are: Visible,Tabstop, Type:dropdown, Owner draw: no, sort and Vertical scroll.

[lobo]

Well, this piece of code along with bare bone winmain & procedure works fine for me:

static HWND cb;
..
case WM_CREATE:
cb = CreateWindow("COMBOBOX", "", WS_VISIBLE | WS_CHILD | WS_TABSTOP | CBS_DROPDOWN | CBS_SORT | WS_VSCROLL, 0, 0, 200, 200, hwnd, 0, (HINSTANCE) GetWindowLong(hwnd, GWL_HINSTANCE), NULL);

SendMessage(cb, CB_ADDSTRING, 0, (LPARAM) "1. lobo");
SendMessage(cb, CB_ADDSTRING, 0, (LPARAM) "2. is");
SendMessage(cb, CB_ADDSTRING, 0, (LPARAM) "3. testing");
SendMessage(cb, CB_ADDSTRING, 0, (LPARAM) "4. cbox");
break;

I'm not qiute sure about need of that WS_VSCROLL, but it works even with it. So i can only recommend you to check carefully all return values and validity of objects you've created.

[Ken Fitlike]

Originally posted by Gravedigga
Owner draw

Which means you have to draw the contents yourself by handling the control parent's WM_DRAWITEM message. If you don't need to do this then remove the owner draw style and it will work as expected.

[lobo]

2Ken

originally posted by Gravedigga
Owner draw: no

If i get this right, this should mean Gravedigga does not use ownerdraw style

[novacain]

I am assuming the combo creates and displays.

Can you click on it and catch a message to it?


lobo

You have set the combo to a child but not given it a resource ID number.

cb = CreateWindow("COMBOBOX", "", WS_VISIBLE | WS_CHILD | WS_TABSTOP | CBS_DROPDOWN | CBS_SORT | WS_VSCROLL, 0, 0, 200, 200, hwnd, 0 , (HINSTANCE) GetWindowLong(hwnd, GWL_HINSTANCE), NULL);

All child windows have to have an individual int ID number. Cast the HMENU param)
ie
,(HMENU)ID_CHILD_CTRL,

[lobo]

novacain:

All child windows have to have an individual int ID number. Cast the HMENU param)

..if you want to be able to retrieve their handles using GetDlgItem() and so. Or you can use static handle to window like i did in my example (which was nothing more then demonstration of functionality, anyway)

[novacain]

"The application determines the child-window identifier; it must be unique for all child windows with the same parent window. " MSDN

That is all controls which are created with the same hwnd MUST have different resource ID values. Not if you feel like it.


>>Or you can use static handle to window like i did in my example

At no point do you explain that you are using a static hwnd.

And Gravedigga DOES use a function that requires the resource ID.

[lobo]

novacain:

0 is unique

My example above does contain declaration of static variable cb, if you look there.

And, at no point i wrote my example is code Gravedigga should use .

I agree, using non-unique ID's is dirty. However, according to my little test and experience, system itself does not seem to have any problems with that. Only problem i'd see would be handling of messages like WM_COMMAND. But in cases you are not using items that are of interest? Like certain statics? Laziness is terrible disease , i know...