Tip 75: Invoking Menu Items in Other Applications with SendMessage

* VB-CODE (1)

Abstract
Within a Visual Basic® application, you can execute a menu item in
another Windows®-based program. This article explains how to use
several Windows application programming interface (API) functions to
execute menu commands.

Executing Menu Commands
In some situations, you may need to actuate an application, such as
Notepad, and execute one or more of that application's menu commands.
The Windows® application programming interface (API) provides several
functions that enable you to perform this type of operation in Visual
Basic®.

- The Windows API FindWindow function can be used to determine the
handle of the application that contains the menu item you want to
execute. FindWindow returns an integer value containing the
application's handle.
- You also need to retrieve the handle associated with the target
window's menu. The GetMenu function will return the handle as an
integer value.
- Once you have the target window's menu handle, you need to determine
the entry's position in the menu and retrieve the handle of the
pop-up menu. In the example program below, we want to retrieve the
handle of the File menu selection. Therefore, we would call the
GetSubMenu function with zero as the entry's position. The first
entry in every pop-up menu always begins with entry number zero.
- Next, we want to retrieve the ID number of the specific menu entry
we want to execute. We retrieve this ID number by calling the
GetMenuItemID function with the entry's position specified as one
(the position of the Open menu selection in the pop-up menu).
- The final step is to make the target application the active
application and to issue the SendMessage function, which in turn
sends a WM_COMMAND message to the target window. The WM_COMMAND
message is set to the target application's window to execute the
File/Open command.

Example Program
The following example program executes another application's menu
commands. This program assumes that the Windows Notepad application
program is already running in memory. This program uses SendMessage to
execute the File/Open menu selection in Notepad.
When you execute the program, click the Command Button. After a second
or two, you will see that Notepad has been activated and that its Open
File dialog box is displayed on the screen.

1. Create a new project in Visual Basic. Form1 is created by default.
2. Add the following Constant and Declare statements to the General
  Declarations section of Form1 (note that each Declare statement
 should be typed as a single line of code):

Private Declare Function FindWindow Lib "User" (ByVal lpClassName
 As Any, ByVal lpWindowName As Any) As Integer
Private Declare Function GetMenu Lib "User" (ByVal hWnd
As Integer) As Integer
Private Declare Function GetMenuItemID Lib "User" (ByVal hMenu
As Integer, ByVal nPos As Integer) As Integer
Private Declare Function GetSubMenu Lib "User" (ByVal hMenu
 As Integer, ByVal nPos As Integer) As Integer
Private Declare Function SendMessage Lib "User" (ByVal hWnd
 As Integer, ByVal wMsg As Integer, ByVal wParam
 As Integer, lParam As Any) As Long
Const WM_COMMAND = &H111

3. Add a Command Button control to Form1. Command1 is created by
  default.
4. Add the following code to the Click event for Command1:

Private Sub Command1_Click()
  Dim hWnd As Integer
  Dim hMainMenu As Integer
  Dim hMenu As Integer
  Dim MenuID As Integer

  hWnd = FindWindow("NotePad", "Untitled - NotePad")
  If hWnd = 0 Then Exit Sub

  hMainMenu = GetMenu(hWnd)
  hMenu = GetSubMenu(hMainMenu, 0)
  MenuID = GetMenuItemID(hMenu, 1)
  AppActivate "Untitled - NotePad"
  X& = SendMessage(hWnd, WM_COMMAND, MenuID, 0&)
End Sub

Additional References
Knowledge Base Q71281. "How to Implement a Bitmap Within a Visual
 Basic Menu." (Development Library, Knowledge Base and Bug Lists)
Knowledge Base Q113475. "How to Get a Window Handle Without Specifying
 an Exact Title." (Development Library, Knowledge Base and Bug Lists)
Windows Help Authoring Guide for Word for Windows 2.0. "Choosing Help
 with the Keyboard." (Development Library, Unsupported Tools and
 Utilities)
"Adding Pop-Up Menus to Your Programs." (Development Library, Books
 and Periodicals, Inside Visual Basic Articles [Cobb])