CS 351 Systems Programming Menus, Dialogs, and Controls

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CS 351 Systems ProgrammingMenus, Dialogs, and
Controls

• Ondrej Hrebicek, Jesse Yurkovich
• October 23rd, 2002

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Introduction to Menus

• Easy to create using Visual Studios Resource
  Editor
• Each selectable menu item is identified by a
  unique ID
• Whenever a menu item is activated, a WM_COMMAND
  message is sent to the owner window together with
  the unique ID
• The main menu, also called the top level menu,
  is located immediately below the caption bar
• Submenus, or drop-down menus, are invoked by
  clicking on items in the main menu, or within the
  submenus themselves
• All menu items have a state they can be
  enabled, disabled, grayed out, checked, or
  unchecked

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Creating a Menu

• In Visual Studio, click on Insert and select
  Resource
• Pick Menu in the dialog box that appears

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Adding Items to a Menu

• In the Resource Editor, double click on an empty
  box
• When entering a caption, add an ampersand before
  the letter to be used as an accelerator it will
  become underlined
• Each leaf menu item also has an ID associated
  with it
• The ID you pick for your items will be sent to
  your applications window procedure along with
  the WM_COMMAND message

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Adding Items to a Menu (2)

• The following code needs to be added to your
  window procedure to capture clicks on the Open
  menu item

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Integrating Menus with your Application

• Possibility 1 - The menus name needs to be
  specified in your window class
• wndclass.lpszMenuName TEXT (MainMenu)
• Possibility 2 - Use LoadMenu () to obtain a
  handle to your menu
• hMenu LoadMenu (hInstance, TEXT (MainMenu))
• hMenu LoadMenu (hInstance, MAKEINTRESOURCE
  (ID_MENU))
• Which you then pass to CreateWindow () or
  SetMenu ()
• CreateWindow (, hMenu, )
• SetMenu (hWnd, hMenu)

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Menu Operations

• Obtaining a handle to a windows menu
• hMenu GetMenu (hWnd)
• Checking and unchecking a menu item
• CheckMenuItem (hMenu, iItemID, MF_CHECKED)
• CheckMenuItem (hMenu, iItemID, MF_UNCHECKED)
• Enabling, disabling, and graying out a menu item
• EnableMenuItem (hMenu, iItemID, MF_ENABLED)
• EnableMenuItem (hMenu, iItemID, MF_DISABLED)
• EnableMenuItem (hMenu, iItemID, MF_GRAYED)

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Floating PopUp Menus

• Can be separate from main menu, or main menus
  submenus
• In order to display a floating popup menu in
  your client area
• Capture the WM_RBUTTONUP message
• Get the x and y coordinates of the mouse clicks
  (stored in the low and high word of lParam,
  respectively)
• Call TrackPopupMenu (hPopupMenu, uFlags, x, y,
  nReserved, hWnd, prcRect)
• Zero or more uFlags specify function options
  (alignment, etc)
• nReserved must always be 0
• prcRect is ignored set to NULL

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Creating a Dialog

• Process is very similar to creating a menu
• Instead of choosing Menu, choose Dialog and
  select the IDD_FORMVIEW style
• Adding controls to the Dialog in the Resource
  Editor is a simple matter of dragging and
  dropping
• Double clicking on a control, as well as the
  dialog itself, will bring up its properties
• Some of these properties need to be modified so
  your program knows how the work with the dialogs
  and their controls
• The most important properties for controls will
  be their ID and their caption
• Dont be afraid to change other properties as
  well many are very effective and often necessary

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Integrating Dialogs with your Application

• The process will be much the same as menus with
  one added caveat
• You must think of Dialogs as a window in and of
  itself - this means all dialogs will get their
  own window procedure to handle their actions
• Use DialogBox () in order to create a dialog and
  display it
• DialogBox (hInst, (LPCTSTR) IDD_LISTVIEW, hWnd,
  (DLGPROC) WndProcListViewDlg)
• IDD_LISTVIEW is the ID you assigned to your
  dialog box in the Resource Editor
• WndProcListViewDlg is your dialogs window
  procedure
• Messages are sent to this procedure in the same
  way as to your main window procedure

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Integrating Dialogs with your Application

• Inside your dialogs window procedure, you will
  often need to handle WM_INITDIALOG and WM_COMMAND
  messages
• WM_COMMAND functions the same way it does for
  menus when controls are manipulated inside the
  dialog box, WM_COMMAND messages are sent to the
  window procedure
• The ID of the control which was manipulated is
  sent with the WM_COMMAND message in the LOWORD of
  lParam
• When the time comes to destroy the dialog box,
  call
• EndDialog (hWnd, LOWORD (wParam))

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More on Controls

• Examples of window controls
• Scrollable Listbox
• Drop down Combo box
• Progress bar
• Radio and check buttons
• All controls, whether they are within a dialog
  or on the main window itself all function the
  same - they all will send a WM_COMMAND message
  whenever theyre manipulated
• You communicate with a control by sending
  messages to it messages can change a controls
  appearance and return information about it

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Listbox Control

• Getting a handle to a Listbox inside a dialog
  where hWnd is the handle to the dialog box
• hListBox GetDlgItem (hWnd, IDC_LIST_LBOX)
• Adding an item to a Listbox
• SendMessage (hListBox, LB_ADDSTRING, 0, (LPARAM)
  string)
• Deleting an item from a Listbox
• SendMessage (hListBox, LB_DELETESTRING, 0, 0)
• Obtaining the position of the item currently
  selected
• int iSelPos SendMessage (hListBox,
  LB_GETCURSEL, 0, 0)