Windows API Guide: SHITEMID Structure

Declare Function TrackPopupMenu Lib "user32.dll" (ByVal hMenu As Long, ByVal uFlags As Long, ByVal x As Long, ByVal y As Long, ByVal nReserved As Long, ByVal hWnd As Long, ByVal prcRect As Long) As Long

Platforms

Windows 95: Supported.
Windows 98: Supported.
Windows NT: Requires Windows NT 3.1 or later.
Windows 2000: Supported.
Windows CE: Requires Windows CE 1.0 or later.

Description & Usage

TrackPopupMenu displays a popup menu at a specified point. The function also tracks the menu, updating the selection highlight until the user either selects an item or otherwise closes the menu. By default, the function sends a WM_COMMAND message to the parent window, notifying it of the selection. However, flags specified in the uFlags parameter can change this behavior.

Return Value

If uFlags contains the TPM_RETURNCMD flag, the function returns the identifier of the menu item that the user selected. If an error occurs or the user does not select an item, the function instead returns 0.

If uFlags does not contain the TPM_RETURNCMD flag, the function returns a nonzero value if the function is successful. If an error occured, the function returns 0. Regardless of uFlags, use the GetLastError to get the error code.

Visual Basic-Specific Issues

None.

Parameters

hMenu

A handle to the popup menu to display and track.

uFlags

A combination of the following flags specifying the positioning of the popup menu and other behavior of the function:

TPM_CENTERALIGN: Position the popup menu so that its horizontal center occurs at the coordinate specified by x.
TPM_LEFTALIGN: Position the popup menu so that its left edge occurs at the coordinate specified by x.
TPM_RIGHTALIGN: Position the popup menu so that its right edge occurs at the coordinate specified by x.
TPM_BOTTOMALIGN: Position the popup menu so that its bottom edge occurs at the coordinate specified by y.
TPM_TOPALIGN: Position the popup menu so that its top edge occurs at the coordinate specified by y.
TPM_VCENTERALIGN: Position the popup menu so that its vertical center occurs at the coordinate specified by y.
TPM_NONOTIFY: Do not send a WM_COMMAND message to the popup menu's parent window to notify it of the user's selection.
TPM_RETURNCMD: Have TrackPopupMenuEx return the identifier of the menu item that the user selected.
TPM_LEFTBUTTON: Only allow the user to select a menu item using the left mouse button (or the keyboard).
TPM_RIGHTBUTTON: Allow the user to select a menu item using either mouse button (or the keyboard).

x

The x-coordinate of the point where the popup menu is to be displayed, relative to the screen.

y

The y-coordinate of the point where the popup menu is to be displayed, relative to the screen.

hWnd

A handle to the window that owns the popup menu. This window will receive the WM_COMMAND message. The window must be specified even if fuFlags contains the TPM_NONOTIFY flag.

prcRect

Ignored -- set to 0.

Constant Definitions

Const TPM_CENTERALIGN = &H4 Const TPM_LEFTALIGN = &H0 Const TPM_RIGHTALIGN = &H8 Const TPM_BOTTOMALIGN = &H20 Const TPM_TOPALIGN = &H0 Const TPM_VCENTERALIGN = &H10 Const TPM_NONOTIFY = &H80 Const TPM_RETURNCMD = &H100 Const TPM_LEFTBUTTON = &H0 Const TPM_RIGHTBUTTON = &H2

Example

' This code is licensed according to the terms and conditions listed here. ' Declarations and such needed for the example: ' (Copy them to the (declarations) section of a module.) Public Declare Function CreatePopupMenu Lib "user32.dll" () As Long Public Declare Function DestroyMenu Lib "user32.dll" (ByVal hMenu As Long) As Long Public Type MENUITEMINFO cbSize As Long fMask As Long fType As Long fState As Long wID As Long hSubMenu As Long hbmpChecked As Long hbmpUnchecked As Long dwItemData As Long dwTypeData As String cch As Long End Type Public Const MIIM_STATE = &H1 Public Const MIIM_ID = &H2 Public Const MIIM_TYPE = &H10 Public Const MFT_SEPARATOR = &H800 Public Const MFT_STRING = &H0 Public Const MFS_DEFAULT = &H1000 Public Const MFS_ENABLED = &H0 Public Declare Function InsertMenuItem Lib "user32.dll" Alias "InsertMenuItemA" (ByVal _ hMenu As Long, ByVal uItem As Long, ByVal fByPosition As Long, lpmii As _ MENUITEMINFO) As Long Public Declare Function TrackPopupMenu Lib "user32.dll" (ByVal hMenu As Long, ByVal _ uFlags As Long, ByVal x As Long, ByVal y As Long, ByVal nReserved As Long, ByVal _ hWnd As Long, ByVal prcRect As Long) As Long Public Const TPM_LEFTALIGN = &H0 Public Const TPM_TOPALIGN = &H0 Public Const TPM_NONOTIFY = &H80 Public Const TPM_RETURNCMD = &H100 Public Const TPM_LEFTBUTTON = &H0 Public Type POINT_TYPE x As Long y As Long End Type Public Declare Function GetCursorPos Lib "user32.dll" (lpPoint As POINT_TYPE) As Long ' When the user clicks button Command1, have a very simple popup menu appear.  The ' menu only has two options, divided by a separator bar.  The menu is created when ' needed and is destroyed after its use. ' The following application-defined constants are used to name the menu item ' identifiers used by this example.  They are not actually part of the API; instead, they are ' used just to eliminate "magic numbers." Private Const ID_ABOUT = 101 Private Const ID_SEPARATOR = 102 Private Const ID_EXIT = 103 Private Sub Command1_Click() Dim hPopupMenu As Long    ' handle to the popup menu to display Dim mii As  MENUITEMINFO  ' describes menu items to add Dim curpos As POINT_TYPE  ' holds the current mouse coordinates Dim menusel As Long       ' ID of what the user selected in the popup menu Dim retval As Long        ' generic return value ' Create the popup menu that will be displayed. hPopupMenu = CreatePopupMenu() ' Add the menu's first item: "About This Problem..." With mii ' The size of this structure. .cbSize = Len(mii) ' Which elements of the structure to use. .fMask = MIIM_STATE Or MIIM_ID Or MIIM_TYPE ' The type of item: a string. .fType = MFT_STRING ' This item is currently enabled and is the default item. .fState = MFS_ENABLED Or MFS_DEFAULT ' Assign this item an item identifier. .wID = ID_ABOUT ' Display the following text for the item. .dwTypeData = "&About This Example..." .cch = Len(.dwTypeData) End With retval = InsertMenuItem(hPopupMenu, 0, 1, mii) ' Add the second item: a separator bar. With mii .fType = MFT_SEPARATOR .fState = MFS_ENABLED .wID = ID_SEPARATOR End With retval = InsertMenuItem(hPopupMenu, 1, 1, mii) ' Add the final item: "Exit". With mii .fType= MFT_STRING .wID = ID_EXIT .dwTypeData = "E&xit" .cch = Len(.dwTypeData) End With retval = InsertMenuItem(hPopupMenu, 2, 1, mii) ' Determine where the mouse cursor currently is, in order to have ' the popup menu appear at that point. retval = GetCursorPos(curpos) ' Display the popup menu at the mouse cursor.  Instead of sending messages ' to window Form1, have the function merely return the ID of the user's selection. menusel = TrackPopupMenu(hPopupMenu, TPM_TOPALIGN Or TPM_LEFTALIGN Or TPM_NONOTIFY _ Or TPM_RETURNCMD Or TPM_LEFTBUTTON, curpos.x, curpos.y, 0, Form1.hWnd, 0) ' Before acting upon the user's selection, destroy the popup menu now. retval = DestroyMenu(hPopupMenu) Select Case menusel Case ID_ABOUT ' Use the Visual Basic MsgBox function to display a short message in a dialog ' box.  Using the MessageBox API function isn't necessary. retval = MsgBox("This example demonstrates how to use the API to display " & _  "a pop-up menu.", vbOkOnly Or vbInformation, "Windows API Guide") Case ID_EXIT ' End this program by closing and unloading Form1. Unload Form1 End Select End Sub