Menus

Menus

Menus also can be specified in resource files. Like dialogs, menus in programs are identified by their names (strings). Menus can be specified both in normal windows and in dialogs. For a normal window, when registering a class, it is sufficient to replace the following string:

 MOV DWORD PTR [WC.CLMENNAME], 0 

Replace this string with the following:

 MOV DWORD PTR [WC.CLMENNAME], OFFSET MENS 

Here, MENS is the name assigned to the menu in the resource file.

For dialogs, menus are set using another method, which, naturally, is also suitable for a normal window. First, the menu is loaded using the LoadMenu function; then, it is set using the setMenu function.

Now, consider this in more detail. Consider the structure of the resource file containing a menu definition. Here is the text of the file containing a menu definition:

 MENUP MENU     {     POPUP "&First item"     {       MENUITEM "&First", 1       MENUITEM "S&econd", 2       POPUP "Subme&nu"       {         MENUITEM "Tent&h item", 6       }     }     POPUP "&Second item"       {       MENUITEM "Th&ird", 3       MENUITEM "F&ourth", 4       }     MENUITEM "E&xit", 5     } 

Carefully look at the menu text. As you can see, menu items have identifiers that the program can use to determine which menu item was chosen . Also note that a drop-down menu can contain a submenu.

Listing 9.3 provides an example of a program that demonstrates the use of a menu with a dialog box.

Listing 9.3: A program with a menu

 // The MENU.RC file // Definitions of constants #define WS_SYSMENU     0x00080000L #define WS_MINIMIZEBOX 0x00020000L #define WS_MAXIMIZEBOX 0x000l0000L #define WS_POPUP       0x80000000L #define WS_CAPTION     0x00C00000L MENUP MENU { POPUP "&First item" {   MENUITEM "&", 1   MENUITEM "&Second", 2 } POPUP "&Second item" {   MENUITEM "& Third", 3   MENUITEM "F&ourth", 4   POPUP "Another sub&menu"   {     MENUITEM "Te&nth subitem", 6   } } MENUITEM "E&xit", 5 } // Identifiers #define IDI_ICON1 100 // Defining the icon IDI_ICON1 ICON "ico1.ico" // Defining the dialog box DIAL1 DIALOG 0, 0, 240, 120 STYLE WS_POPUP  WS_CAPTION  WS_SYSMENU  WS_MINIMIZEBOX                              WS_MAXIMIZEBOX CAPTION "An example dialog box" FONT 8, "Arial" { } ; The MENU.INC file ; Constants ; The message arrives when the window is closed WM_CLOSE      equ 10h WM_INITDIALOG equ 110h WM_SETICON    equ 80h WM_COMMAND    equ 111h ; Prototypes of external procedures EXTERN      MessageBoxA@16:NEAR EXTERN      ExitProcess@4:NEAR EXTERN      GetModuleHandleA@4:NEAR EXTERN      DialogBoxParamA@20:NEAR EXTERN      EndDialog@8:NEAR EXTERN      LoadStringA@16:NEAR EXTERN      LoadIconA@8:NEAR EXTERN      LoadMenuA@8:NEAR EXTERN      SendMessageA@16:NEAR EXTERN      SetMenu@8:NEAR ; Structures ; Message structure MSGSTRUCT STRUC         MSHWND      DD ?         MSMESSAGE   DD ?         MSWPARAM    DD ?         MSLPARAM    DD ?         MSTIME      DD ?         MSPT        DD ? MSGSTRUCT ENDS ; The MENU.ASM file .586P ; Flat memory model .MODEL FLAT, stdcall include menu.inc ; INCLUDELIB directives for the linker includelib c:\masm32\lib\user32.lib includelib c:\masm32\lib\kernel32.lib ;------------------------------------------- ; Data segment _DATA SEGMENT         MSG    MSGSTRUCT <?>         HINST  DD 0 ; Application descriptor         PA     DB "DIAL1", 0         PMENU  DB "MENUP", 0         STR1   DB "Exit the program", 0         STR2   DB "Message", 0 _DATA ENDS ; Code segment _TEXT SEGMENT START: ; Get the application descriptor     PUSH  0     CALL  GetModuleHandleA@4     MOV   [HINST],' EAX ;-----------------------------     PUSH  0     PUSH  OFFSET WNDPROC     PUSH  0     PUSH  OFFSET PA     PUSH  [HINST]     CALL  DialogBoxParamA@20     CMP   EAX, -1     JNE   KOL KOL:     PUSH  0     CALL  ExitProcess@4 ; Window procedure ; Parameter positions in the stack ; [EBP+014H]  LPARAM ; [EBP+10H]  WAPARAM ; [EBP+0CH]  MES ; [EBP+8]    HWND WNDPROC PROC     PUSH  EBP     MOV   EBP, ESP     PUSH  EBX     PUSH  ESI     PUSH  EDI ;-------------------------     CMP   DWORD PTR [EBP+0CH], WM_CLOSE     JNE   L1 ; Close the dialog     PUSH  0     PUSH  DWORD PTR [EBP+08H]     CALL  EndDialog@8     JMP   FINISH L1:     CMP   DWORD PTR [EBP+0CH], WM_INITDIALOG     JNE   L2 ; Load the icon     PUSH  100  ; Icon identifier     PUSH  [HINST]; Process identifier     CALL  LoadIconA@8 ; Set the icon     PUSH  EAX     PUSH  0 ; Icon type (small)     PUSH  WM_SETICON     PUSH  DWORD PTR [EBP+08H]     CALL  SendMessageA@16 ; Load the menu     PUSH  OFFSET PMENU     PUSH  [HINST]     CALL  LoadMenuA@8 ; Set the menu     PUSH  EAX     PUSH  DWORD PTR [EBP+08H]     CALL  SetMenu@8     JMP   FINISH L2: ; Checking whether something has happened to the ; controls in the dialog ; In this case, there is only one ; control --- the menu     CMP   DWORD PTR [EBP+0CH], WM_COMMAND     JNE   FINISH ; Determining the identifier ; In this case, this is the menu item identifier     CMP   WORD PTR [EBP+10H], 5     JNE   FINISH ; Message     PUSH  0 ; MB_OK     PUSH  OFFSET STR2     PUSH  OFFSET STR1     PUSH  0     CALL  MessageBoxA@16 ; Close the dialog     PUSH  0     PUSH  DWORD PTR [EBP+08H]     CALL  EndDialog@8 FINISH:     MOV   EAX, 0     POP   EDI     POP   ESI     POP   EBX     POP   EBP     RET   16 WNDPROC ENDP _TEXT ENDS END START 

 

It is necessary to provide a small comment about the program from Listing 9.3. First, pay attention to the transparent analogy between the dialog and the menu. In both cases, the resource is defined by its name instead of its identifier. Furthermore, both the dialog and the menu contain elements defined by identifiers, which have been specified in the resource file and placed into the least significant word of the WPARAM parameter.

In Listing 9.3, you load the menu programmatically. It is possible to use a different approach: Specify the menu in dialog options as follows :

 // Dialog definition     DIAL1 DIALOG 0, 0, 240, 120     STYLE WS_POPUP  WS_CAPTION  WS_SYSMENU  WS_MINIMIZEBOX                      WS_MAXIMIZEBOX     MENU MENUP     CAPTION "Dialog example"     FONT 8, "Arial"     {     } 

This is sufficient to automatically load and display the menu.

Recall that in Chapter 3 an example was provided, in which a button was created as a child window. The event related to clicking this button was identified by the content of the LPARAM of the button descriptor. As you can see, the element of the dialog can be identified both by the resource descriptor and by the resource identifier.

Now, return to the menu. Menu items can contain additional parameters that define additional properties of those items. The resource compiler recognizes the following properties:

• CHECKED The item is selected with a check mark.

• GRAYED The element is unavailable (and displayed in gray).

• HELP The element has an associated help string. Resource editors create an additional string resource. The string identifier matches that of the menu item.

• MENUBARBREAK For a horizontal menu item, this means that starting from it, all further horizontal menu items are located in a new line. For a vertical item, this means that all further items start from a new column. The items are separated by a line delimiter .

• MENUBREAK This is similar to the previous property, but no separating line is present.

• INACTIVE This menu item doesn't work.

• SEPARATOR This item creates a separator in the menu but doesn't provide an identifier.

To conclude the menu description, I'll note that Windows provides a range of functions that can be used to change menu properties (e.g., to add or remove items or to modify their properties). In the next chapter, I'll provide several examples of functions from this group .