How do I create two different comboboxes with different strings of items? - c++

Question

I have created a combo box having a list of items. How do I create another one with different strings of items? Can I in anyway change the hWnd because it seems the first already has the hWndCombobxes. Thus, when I apply it to the second, I get an error message, indicating that there is a duplicate value.
Below is the code I have. What function should I call else?
case WM_CREATE: {
HWND hWndComboBox = CreateWindow (TEXT("COMBOBOX"), TEXT (""),
CBS_DROPDOWN| CBS_HASSTRINGS | WS_VSCROLL| WS_VISIBLE | WS_CHILD ,
100, 150, 200, 150,
hwnd ,(HMENU) ID_COMBOBOX 1, NULL, NULL);
// ADD 2 ITEMS
SendMessage (
hWndComboBox,
(UINT) CB_ADDSTRING,
(WPARAM) 0, (LPARAM) TEXT ("Item 1"));
SendMessage (
hWndComboBox ,
(UINT) CB_ADDSTRING,
(WPARAM) 0, (LPARAM) TEXT ("Item 2"));
// SEND THE CB_SETCURSEL MESSAGE TO DISPLAY AN INITIAL ITEM IN SELECTION FIELD
SendMessage (hWndComboBox , LB_SETCURSEL , (WPARAM) 0, (LPARAM) 1);

Answer 1

// put this declaration somewhere up (or better move it to an include file)
#define ID_COMBOBOX_1 1001
#define ID_COMBOBOX_2 1002
// end defines
case WM_CREATE: {
// it is preferably to use SendDlgItemMessage instead of SendMessage
// this make things easier
// you will not need combobox's HWND, just ComboBox ID
TCHAR *Combo_1_Data[]={
TEXT("Item 1"),
TEXT("Item 2")
};
TCHAR *Combo_2_Data[]={
TEXT("Element 1"),
TEXT("Element 2")
};
int i;
// create two different ComboBoxs
CreateWindow (TEXT("COMBOBOX"), TEXT (""),
CBS_DROPDOWN| CBS_HASSTRINGS | WS_VSCROLL| WS_VISIBLE | WS_CHILD ,
100, 150, 200, 150,
hwnd ,(HMENU) ID_COMBOBOX_1, NULL, NULL);
CreateWindow (TEXT("COMBOBOX"), TEXT (""),
CBS_DROPDOWN| CBS_HASSTRINGS | WS_VSCROLL| WS_VISIBLE | WS_CHILD ,
208, 150, 200, 150,
hwnd ,(HMENU) ID_COMBOBOX_2, NULL, NULL);
// Fill first Combo with its Data
for( i = 0 ; i < (sizeof(Combo_1_Data) / sizeof(Combo_1_Data[0]) ) ; i++ ){
SendDlgItemMessage (hwnd,ID_COMBOBOX_1 ,CB_ADDSTRING, 0, (LPARAM) Combo_1_Data[i]);
}
SendDlgItemMessage (hwnd, ID_COMBOBOX_1 , LB_SETCURSEL , (WPARAM) 0, (LPARAM) 1);
// Fill second Combo with its Data
for( i = 0 ; i < (sizeof(Combo_2_Data) / sizeof(Combo_2_Data[0] )) ; i++ ){
SendDlgItemMessage (hwnd,ID_COMBOBOX_2 ,CB_ADDSTRING, 0, (LPARAM) Combo_2_Data[i]);
}
SendDlgItemMessage (hwnd, ID_COMBOBOX_2 , LB_SETCURSEL , (WPARAM) 0, (LPARAM) 1);

Answer 2

Copy and paste the other combobox. Do the same for the 'Send message' function. Then change the hWnd of the second Combobox to hWndListBox. Do the same to 'Send message'.
HWND hWndListBox = CreateWindow (TEXT("COMBOBOX"), TEXT (""),
CBS_DROPDOWN| CBS_HASSTRINGS | WS_VSCROLL| WS_VISIBLE | WS_CHILD ,
100, 70, 200, 90,
hwnd ,(HMENU) NULL, NULL, NULL);
HWND hWndComboBox = CreateWindow (TEXT("COMBOBOX"), TEXT (""),
CBS_DROPDOWN| CBS_HASSTRINGS | WS_VSCROLL| WS_VISIBLE | WS_CHILD ,
100, 150, 200, 100,
hwnd ,(HMENU) NULL, NULL, NULL);
SendMessage (
hWndComboBox ,
(UINT) CB_ADDSTRING,
(WPARAM) 0, (LPARAM) TEXT ("Item 2"));
SendMessage (
hWndListBox ,
(UINT) CB_ADDSTRING,
(WPARAM) 0, (LPARAM) TEXT ("Item 1"));
// SEND THE CB_SETCURSEL MESSAGE TO DISPLAY AN INITIAL ITEM IN SELECTION FIELD
SendMessage (hWndComboBox , CB_SETCURSEL , (WPARAM) 0, (LPARAM) 0);
SendMessage (hWndListBox , CB_SETCURSEL , (WPARAM) 0, (LPARAM) 0);