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Visual Basic Subclassing Routines Shell_NotifyIcon: Respond to Systray Icon/Menu Interaction in a MDI App |
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Posted: | Saturday July 31, 1999 | |
Updated: | Monday December 26, 2011 | |
Applies to: | VB5, VB6 | |
Developed with: | VB6, Windows NT4 | |
OS restrictions: | None | |
Author: | VBnet - Randy Birch | |
Related: |
Shell_NotifyIcon: Windows Systray NOTIFYICONDATA Overview
Shell_NotifyIcon: Add Icon to Windows System Tray
Shell_NotifyIcon: Display Systray Balloon Tips |
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Prerequisites |
VB5 or VB6. All code will be created from this page.
Note: You will need to be running Windows95 OSR2, Windows98, WinNT4 or Win2000 in order to use the GetDiskFreeSpaceEx API below (see the comments section at the end of the page for more info). This demo contains new code added January 2003 to properly determine the Shell32.dll version and use the appropriately-sized NOTIFYICONDATA structure. Although this will handle the display of the systray icon across Windows versions, application designers targeting Windows 2000 and XP should nonetheless take appropriate steps to ensure their app degrades gracefully to utilize only the functionality provided in earlier system's shell versions. For information concerning using the systray across all Windows versions it is strongly recommended you refer to Shell_NotifyIcon: Windows Systray NOTIFYICONDATA Overview. |
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The
procedure to create and manipulate a shell systray icon from a MDI parent form is very similar to the method used in a SDI application.
Detailed explanations of the Shell_NotifyIcon methods have been provided in the proceeding two pages (above), so this demo will only provide
the comments where there code differs from that mentioned before.
This demo shows how to create the advanced Systray Popup demo using a MDI parent (frmMDIMain - to house the drive menu) and with two MDI child windows (frmChild, displaying a label and with a single menu item, and frmChildDrvInfo, displaying the actual drive statistics). Since the MDI parent in this example houses the popup menu that serves as both a systray popup menu as well as a visible &File menu, it receives the actual subclassing. In this demo, frmChild also receives a menu, to point out an interesting phenomenon that occurs when either or both of the Child forms do have menus. As per MDI mandate, the child menu will replace the menu bar on the MDI parent. But the popup is still accessible via subclassing, meaning that your application can subclass the MDI parent and still show and react to normal child menus without losing any of the parent's systray popup functionality. This project requires three forms:To a new MDI form (frmMDIMain), add a parent menu bar item named 'zmnuDemo', and under it a single menu array element (mnuDriveDetails(0)). Assure that it is an menu array element, and ignore the caption - this will be dynamically created based on the drives installed at program execution. For demo purposes I left the menu visible on the form above, but it can be invisible. Set the project start-up form to frmMDIMain. To a second form (frmChild), set its MDIChild property True, and add any menu element. Inside the menu event, add a simple msgbox call - i.e. "MsgBox "Called from Child form" For the third form (frmChildDrvInfo), you may wnat to copy the DrvInfo form created in the SDI Advanced demo, to save recreating. If you're starting from scratch, on frmChildDrvInfo add three labels for the statistic descriptions, and a second array of three labels (lbInfo(0) - lbInfo(2)) to receive the actual stats. Add the Microsoft Chart Control to the project via the Components menu, and add a chart (MSChart1) to the form. Set the chart type to 14 - Pie. Optionally set the colours as desired. Set the charts ColumnCount to 2, and RowCount to 1. Add two picture boxes (Picture1/Picture2), and set their BackColor to represent the chart legend. Finally, add a command button (cmdOK). |
BAS Module 1 Code - ShellNotifyMDI.bas |
Place the following code into the general declarations area of a bas module: |
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Option Explicit '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Copyright ©1996-2011 VBnet/Randy Birch, All Rights Reserved. ' Some pages may also contain other copyrights by the author. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Distribution: You can freely use this code in your own ' applications, but you may not reproduce ' or publish this code on any web site, ' online service, or distribute as source ' on any media without express permission. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 'Required Public constants, types & declares 'for the Shell_NotifyIcon methods Public Const NIM_ADD As Long = &H0 Public Const NIM_MODIFY As Long = &H1 Public Const NIM_DELETE As Long = &H2 Public Const NIF_ICON As Long = &H2 'adding an ICON Public Const NIF_TIP As Long = &H4 'adding a TIP Public Const NIF_MESSAGE As Long = &H1 'want return messages 'rodent constant we'll need for the callback Public Const WM_LBUTTONDOWN As Long = &H201 Public Const WM_LBUTTONUP As Long = &H202 Public Const WM_LBUTTONDBLCLK As Long = &H203 Public Const WM_MBUTTONDOWN As Long = &H207 Public Const WM_MBUTTONUP As Long = &H208 Public Const WM_MBUTTONDBLCLK As Long = &H209 Public Const WM_RBUTTONDOWN As Long = &H204 Public Const WM_RBUTTONUP As Long = &H205 Public Const WM_RBUTTONDBLCLK As Long = &H206 'shell version / NOTIFYICONDATA struct size constants Public Const NOTIFYICONDATA_V1_SIZE As Long = 88 'pre-5.0 structure size Public Const NOTIFYICONDATA_V2_SIZE As Long = 488 'pre-6.0 structure size Public Const NOTIFYICONDATA_V3_SIZE As Long = 504 '6.0+ structure size Public NOTIFYICONDATA_SIZE As Long Public Type GUID Data1 As Long Data2 As Integer Data3 As Integer Data4(7) As Byte End Type Public Type NOTIFYICONDATA cbSize As Long hWnd As Long uID As Long uFlags As Long uCallbackMessage As Long hIcon As Long szTip As String * 128 dwState As Long dwStateMask As Long szInfo As String * 256 uTimeoutAndVersion As Long szInfoTitle As String * 64 dwInfoFlags As Long guidItem As GUID End Type Public NID As NOTIFYICONDATA Public Declare Function Shell_NotifyIcon Lib "shell32" _ Alias "Shell_NotifyIconA" _ (ByVal dwMessage As Long, _ lpData As NOTIFYICONDATA) As Long Private Declare Function GetFileVersionInfoSize Lib "version.dll" _ Alias "GetFileVersionInfoSizeA" _ (ByVal lptstrFilename As String, _ lpdwHandle As Long) As Long Private Declare Function GetFileVersionInfo Lib "version.dll" _ Alias "GetFileVersionInfoA" _ (ByVal lptstrFilename As String, _ ByVal dwHandle As Long, _ ByVal dwLen As Long, _ lpData As Any) As Long Private Declare Function VerQueryValue Lib "version.dll" _ Alias "VerQueryValueA" _ (pBlock As Any, _ ByVal lpSubBlock As String, _ lpBuffer As Any, _ nVerSize As Long) As Long Private Declare Sub CopyMemory Lib "kernel32" _ Alias "RtlMoveMemory" _ (Destination As Any, _ Source As Any, _ ByVal Length As Long) Public Function IsShellVersion(ByVal version As Long) As Boolean 'returns True if the Shell version '(shell32.dll) is equal or later than 'the value passed as 'version' Dim nBufferSize As Long Dim nUnused As Long Dim lpBuffer As Long Dim nVerMajor As Integer Dim bBuffer() As Byte Const sDLLFile As String = "shell32.dll" nBufferSize = GetFileVersionInfoSize(sDLLFile, nUnused) If nBufferSize > 0 Then ReDim bBuffer(nBufferSize - 1) As Byte Call GetFileVersionInfo(sDLLFile, 0&, nBufferSize, bBuffer(0)) If VerQueryValue(bBuffer(0), "\", lpBuffer, nUnused) = 1 Then CopyMemory nVerMajor, ByVal lpBuffer + 10, 2 IsShellVersion = nVerMajor >= version End If 'VerQueryValue End If 'nBufferSize End Function Public Sub SetShellVersion() Select Case True Case IsShellVersion(6) NOTIFYICONDATA_SIZE = NOTIFYICONDATA_V3_SIZE '6.0+ structure size Case IsShellVersion(5) NOTIFYICONDATA_SIZE = NOTIFYICONDATA_V2_SIZE 'pre-6.0 structure size Case Else NOTIFYICONDATA_SIZE = NOTIFYICONDATA_V1_SIZE 'pre-5.0 structure size End Select End Sub Public Function ShellTrayAdd(frm As Form) As Long 'prepare the NOTIFYICONDATA type with the 'required parameters: 'for information on the data structure members, 'please see the other Advanced topic at the top 'of the page. If NOTIFYICONDATA_SIZE = 0 Then SetShellVersion With NID .cbSize = NOTIFYICONDATA_SIZE .hwnd = frm.hwnd .uID = 125& .uFlags = NIF_ICON Or NIF_TIP Or NIF_MESSAGE .uCallbackMessage = WM_MYHOOK .hIcon = frm.Icon .szTip = "VBnet MDI System Tray Callback Demo" & Chr$(0) End With Call Shell_NotifyIcon(NIM_ADD, NID) End Function Public Sub ShellTrayRemove() 'Remove the icon from the taskbar Call Shell_NotifyIcon(NIM_DELETE, NID) End Sub Public Sub SubClass(hwnd As Long) 'assign our own window message 'procedure (WindowProc) On Error Resume Next defWindowProc = SetWindowLong(hwnd, GWL_WNDPROC, AddressOf WindowProc) End Sub Public Sub UnSubClass() 'restore the default message handling 'before exiting If defWindowProc Then SetWindowLong frmMDIMain.hwnd, GWL_WNDPROC, defWindowProc defWindowProc = 0 End If End Sub |
BAS Module 2 Code - WindowProcMDI.bas |
Place the following code into the general declarations area of a second bas module: |
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Option Explicit '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Copyright ©1996-2011 VBnet/Randy Birch, All Rights Reserved. ' Some pages may also contain other copyrights by the author. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Distribution: You can freely use this code in your own ' applications, but you may not reproduce ' or publish this code on any web site, ' online service, or distribute as source ' on any media without express permission. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 'defWindowProc: Variable to hold the ID of the ' default window message processing ' procedure. Returned by SetWindowLong. Public defWindowProc As Long 'Get/SetWindowLong messages Public Const GWL_WNDPROC As Long = (-4) Public Const GWL_HWNDPARENT As Long = (-8) Public Const GWL_ID As Long = (-12) Public Const GWL_STYLE As Long = (-16) Public Const GWL_EXSTYLE As Long = (-20) Public Const GWL_USERDATA As Long = (-21) 'general windows messages Public Const WM_USER As Long = &H400 Public Const WM_NOTIFY As Long = &H4E Public Const WM_COMMAND As Long = &H111 'we need to define a message that we will 'respond to when sent from the systray icon, 'so create one using WM_APP Private Const WM_APP As Long = &H8000& Public Const WM_MYHOOK As Long = WM_APP + &H15 Public Declare Function SetForegroundWindow Lib "user32" _ (ByVal hwnd As Long) As Long Public Declare Function PostMessage Lib "user32" _ Alias "PostMessageA" _ (ByVal hwnd As Long, _ ByVal wMsg As Long, _ ByVal wParam As Long, _ lParam As Any) As Long Public Declare Function GetWindowLong Lib "user32" _ Alias "GetWindowLongA" _ (ByVal hwnd As Long, _ ByVal nIndex As Long) As Long Public Declare Function SetWindowLong Lib "user32" _ Alias "SetWindowLongA" _ (ByVal hwnd As Long, _ ByVal nIndex As Long, _ ByVal dwNewLong As Any) As Long Public Declare Function CallWindowProc Lib "user32" _ Alias "CallWindowProcA" _ (ByVal lpPrevWndFunc As Long, _ ByVal hwnd As Long, _ ByVal uMsg As Long, _ ByVal wParam As Long, _ ByVal lParam As Long) As Long Public Function WindowProc(ByVal hwnd As Long, _ ByVal uMsg As Long, _ ByVal wParam As Long, _ ByVal lParam As Long) As Long 'window message procedure ' 'If the handle returned is to our form, 'call a form-specific message handler to 'deal with the tray notifications. If it 'is a general system message, pass it on to 'the default window procedure. ' 'If it's ours, we look at lParam for the 'message generated, and react appropriately. On Error Resume Next Select Case hwnd 'form-specific handler Case frmMDIMain.hwnd Select Case uMsg 'check uMsg for the application-defined 'identifier (NID.uID) assigned to the 'systray icon in NOTIFYICONDATA (NID). 'WM_MYHOOK was defined as the message sent 'as the .uCallbackMessage member of 'NOTIFYICONDATA the systray icon Case WM_MYHOOK 'lParam is the value of the message 'that generated the tray notification. Select Case lParam Case WM_RBUTTONUP: 'assure that when the popup menu closes 'focus returns to our app Call SetForegroundWindow(frmMDIMain.hwnd) 'show the popup from the MDI parent frmMDIMain.PopupMenu frmMDIMain.zmnuDemo End Select 'handle any other form messages by 'passing to the default message proc Case Else WindowProc = CallWindowProc(defWindowProc, _ hwnd, _ uMsg, _ wParam, _ lParam) Exit Function End Select 'this takes care of messages when the 'handle specified is not that of the form Case Else WindowProc = CallWindowProc(defWindowProc, _ hwnd, _ uMsg, _ wParam, _ lParam) End Select End Function Public Function FARPROC(ByVal pfn As Long) As Long 'A dummy procedure that receives and returns 'the value of the AddressOf operator. 'Obtain and set the address of the callback 'This workaround is needed as you can't assign 'AddressOf directly to a member of a user- 'defined type, but you can assign it to another 'long and use that (as returned here) FARPROC = pfn End Function |
Form 1 Code - frmMDIMain.frm |
To the main MDI form - frmMDIMain - add the following code: |
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Option Explicit 'needed locally in this form Private Declare Function GetLogicalDriveStrings Lib "kernel32" _ Alias "GetLogicalDriveStringsA" _ (ByVal nBufferLength As Long, _ ByVal lpBuffer As String) As Long Private Declare Function GetDriveType Lib "kernel32" _ Alias "GetDriveTypeA" _ (ByVal nDrive As String) As Long Private Const DRIVE_UNKNOWN As Long = 0 Private Const DRIVE_NO_ROOT_DIR As Long = 1 Private Const DRIVE_REMOVABLE As Long = 2 Private Const DRIVE_FIXED As Long = 3 Private Const DRIVE_REMOTE As Long = 4 Private Const DRIVE_CDROM As Long = 5 Private Const DRIVE_RAMDISK As Long = 6 Private Sub MDIForm_Load() 'saves me searching the disk for the old drive icon, 'and because a child form's property is referenced, 'this loads the child! Me.Icon = frmChild.Icon 'add an icon to the system tray ShellTrayAdd Me CreateDriveMenu 'prepare to receive the systray events SubClass frmMDIMain.hwnd End Sub Private Sub CreateDriveMenu() Dim c As Long Dim drvType As String Dim drvName As String Dim allDrives As String 'get the list of all available drives allDrives = rgbGetLogicalDriveStrings() 'Separate the drive strings and add them 'to the menu. Do Until allDrives = Chr(0) 'strip off one drive item from allDrives drvName = StripNulls(allDrives) drvType = GetDriveString(drvName) 'add a new entry to the drive to the menu, 'skipping menu array item 0 If c > 0 Then Load mnuDriveDetails(c) mnuDriveDetails(c).Caption = drvName & " stats " & drvType mnuDriveDetails(c).Visible = True c = c + 1 Loop 'add a separator and the Close and Exit options Load mnuDriveDetails(c) mnuDriveDetails(c).Visible = True mnuDriveDetails(c).Caption = "-" c = c + 1 Load mnuDriveDetails(c) mnuDriveDetails(c).Visible = True mnuDriveDetails(c).Caption = "Close Tray icon" c = c + 1 Load mnuDriveDetails(c) mnuDriveDetails(c).Visible = True mnuDriveDetails(c).Caption = "Exit" End Sub Private Function rgbGetDriveType(thisDrv As String) As String 'returns string representing the type of drive. Select Case GetDriveType(thisDrv) Case DRIVE_UNKNOWN: rgbGetDriveType = "[unknown]" Case DRIVE_NO_ROOT_DIR: rgbGetDriveType = "[error: no root]" Case DRIVE_REMOVABLE: Select Case Left$(thisDrv, 1) Case "a", "b": rgbGetDriveType = "[floppy]" Case Else: rgbGetDriveType = "[removable]" End Select Case DRIVE_FIXED: rgbGetDriveType = "[hard drive]" Case DRIVE_REMOTE: rgbGetDriveType = "[network]" Case DRIVE_CDROM: rgbGetDriveType = "[CD-ROM]" Case DRIVE_RAMDISK: rgbGetDriveType = "[RAM disk]" End Select End Function Private Function GetDriveString() As String 'returns string of available 'drives each separated by a null Dim sBuffer As String 'possible 26 drives, three characters each, plus trailing null sBuffer = Space$(26 * 4) If GetLogicalDriveStrings(Len(sBuffer), sBuffer) Then 'do not trim off trailing null! GetDriveString = Trim$(sBuffer) End If End Function Private Function StripNulls(startstr As String) As String 'Take a string separated by Chr$(0) 'and split off 1 item, shortening the 'string so next item is ready for removal. Dim pos As Long pos = InStr(startstr$, Chr$(0)) If pos Then StripNulls = Mid$(startstr, 1, pos - 1) startstr = Mid$(startstr, pos + 1, Len(startstr)) End If End Function Private Sub MDIForm_Unload(Cancel As Integer) 'Remove the icon added to the taskbar ShellTrayRemove 'remove subclassing UnSubClass 'assure unloading proceeds Cancel = False End Sub Private Sub mnuDriveDetails_Click(Index As Integer) Const WM_CLOSE = &H10 Select Case Index 'the last menu item - exit Case mnuDriveDetails.Count - 1 'Executing 'Unload Me' from within a 'menu event invoked from a systray icon 'will cause a GPF. The proper way to 'terminate under these circumstances 'is to send a WM_CLOSE message to the 'form. The form will process the 'message as though the user had selected 'Close from the sysmenu, invoking the 'normal chain of shutdown events, removing 'the tray icon, terminating the subclassing 'cleanly and ultimately preventing the GPF. ' 'This code can also be called directly from 'the form's menu as well, so no special coding 'is required to differentiate between an end 'command from a popup systray menu, or from 'a normal form menu. ' 'The UnloadMode of QueryUnload/UnloadMode 'will equal vbFormControlMenu when this 'close method is used. Call PostMessage(frmMDIMain.hwnd, WM_CLOSE, 0&, ByVal 0&) 'the second-last menu item - close icon Case mnuDriveDetails.Count - 2 'nuke the systray item ShellTrayRemove 'a drive stats item Case Else 'pretty straight forward. ' 'get the drive from the caption (i.e. c:\) 'pass to the frmChildDrvInfo form and show. Dim currDrive As String currDrive = Left$(mnuDriveDetails(Index).Caption, 3) 'Once form 'frmChildDrvInfo' gets the letter 'and GetDriveStats is called, the form 'retrieves the drive stats and creates 'the stat details before displaying. With frmChildDrvInfo .DriveToGet currDrive .GetDriveStats .Show End With End Select End Sub |
Form 2 Code - frmMDIChild.frm |
To the MDI child form - frmChild - add the following code: |
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Option Explicit Private Sub Form_Load() Dim msg As String msg = "Systray Tooltip && Popup Menu Demo for MDI Windows." & vbCrLf & vbCrLf msg = msg & "Move the mouse over the systray 'drive'" msg = msg & " icon. The tooltip will appear." & vbCrLf & vbCrLf msg = msg & "Right-clicking displays the popup menu. " msg = msg & "Choose an option." 'assign and size the label Label1.Move (Me.Width - Label2.Width) \ 2, (Me.Height - Label2.Height) \ 2 Label1.Caption = msg End Sub |
Form 3 Code - frmChildDrvInfo.frm |
If you are recreating the drvInfo form from scratch, add the following code to frmChildDrvInfo: |
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Option Explicit 'this handles both partitions < 2 > gig Private Declare Function GetDiskFreeSpaceEx Lib "kernel32" _ Alias "GetDiskFreeSpaceExA" _ (ByVal lpcurrDrive As String, _ lpFreeBytesAvailableToCaller As Currency, _ lpTotalNumberOfBytes As Currency, _ lpTotalNumberOfFreeBytes As Currency) As Long 'passed as a parameter from the main form 'menu click (to the sub 'DriveToGet') Private workDrv As String Private Sub Form_Load() 'Even though this is a child form, we can 'centre this form in the MDI parent Me.Move (frmMDIMain.Width - Me.Width) \ 2, (frmMDIMain.Height - Me.Height) \ 2 'still saves me searching all 'over the place for the icon! Me.Icon = frmMDIMain.Icon End Sub Private Sub cmdOK_Click() Unload Me End Sub Public Sub DriveToGet(selectedDrive As String) workDrv = selectedDrive End Sub Public Sub GetDriveStats() Dim TotalBytes As Currency Dim TotalFree As Currency Dim FreeToCaller As Currency 'some temp vars for calculations Dim tmp As Currency Dim tmpTotal As Currency Dim tmpFree As Currency 'passed empty and filled in the 'CreateChartStats sub Dim pcUsed As Single Dim pcFree As Single 'get the drive space info Call GetDiskFreeSpaceEx(workDrv, FreeToCaller, TotalBytes, TotalFree) 'since we're using a chart, the values 'need to be turned into percentages (tmp) 'and the chart filled 'If values were returned (disk present), 'calc the percentage free multiplying 'the returned values of TotalBytes and 'TotalFree by 10000 to adjust for the '4 decimal places that the currency 'data type returns. tmpTotal = (TotalBytes * 10000) tmpFree = (TotalFree * 10000) If TotalBytes > 0 Then tmp = (tmpFree / tmpTotal) 'now pass the drive and tmp (even if 0) 'to the chart routine. The sub returns 'pcUsed and pcFree for use below. CreateChartStats workDrv, tmp, pcUsed, pcFree 'show the results lbInfo(0).Caption = Format$(tmpFree, "###,###,###,##0") & " bytes " & pcFree & "%" lbInfo(1).Caption = Format$(tmpTotal - tmpFree, "###,###,###,##0") & " bytes " & pcUsed & "%" lbInfo(2).Caption = Format$(tmpTotal, "###,###,###,##0") & " bytes" End Sub Private Sub CreateChartStats(workDrv As String, tmp, pcUsed, pcFree) 'reduce the values to percent pcFree = Int(tmp * 100) pcUsed = Int(100 - pcFree) 'and fill in a chart With MSChart1 .chartType = 14 .ShowLegend = False .ColumnCount = 2 .RowCount = 1 .RowLabel = "Drive " & UCase$(Left$(workDrv, 1)) .Column = 1 .Row = 1 .Data = pcUsed .Column = 2 .Row = 1 .Data = pcFree End With End Sub |
Comments |
Again. double check all your code, in particular the form,
menu and control names. Save the project, then run using the Start With
Full Compile option to catch any errors before they hit during
subclassing. Because a reference was made to the MDI Child form's icon property, frmChild will
appear in the MDI window, and its menu will have replaced the drive info menu created on the MDI parent. Once started the MID Parent form's
icon will appear in the taskbar. By leaving the mouse over the icon, the icon's ToolTip will appear. Right-clicking over the icon will
display the popup menu listing the drives and drive types available on the system, even though the menu has actually been replaced by the
frmChild menu. Making a selection will invoke frmChildDrvInfo displaying the drive's statistics. Selecting Close Tray Icon will remove
the icon from the tray.
If you were to issue an Unload frmMDIMain command via the sys tray popup menu, while subclassing was still activated, you will generate a GPF. Therefore the code shown here uses another technique to allow application termination - it posts to itself a WM_CLOSE message. This is processed after the menu event has completed, and results in a UnloadMode message similar to pressing the X button or selecting the system menu's Close option. The Unload event fires, and subclassing is safely terminated. Beginning with the introduction of Windows95 OEM Service Pack 2 and its Fat32 disk system, and continuing through the Fat32-able Windows 98, the correct API to call for systems with drive partitions greater then 2 gigabytes is GetDiskFreeSpaceEx. NT4 also supports GetDiskFreeSpaceEx. The OEM Service Pack 2 version of Windows95, and Windows 98, provides among other enhancements, optional support for FAT32 partitions, allowing a single partition of up to 5 gigabytes with a cluster size of only 4k. The original release version of Windows95 supports only partitions or drives up to 2 gigabytes in size. Using the GetDiskFreeSpaceEx code above on older original Win95 systems will return an 'error 453 - Entry point not found for GetDiskFreeSpaceEx'. On these older systems, the correct API to use is GetDiskFreeSpace. For code that will use either of the two APIs based on their presence in kernel32, see the method employed in GetDiskFreeSpaceEx: Detailed Drive Info Microsoft recommends obtaining the user's version of Windows using GetVersionEx prior to calling the free space APIs. |
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Copyright ©1996-2011 VBnet and Randy Birch. All Rights Reserved. |