How to use the System Tray directly from Visual Basic

Summary

This article demonstrates how to take full advantage of the Windows System Tray, or Taskbar Notification Area, using Visual Basic. It places an icon of your choice into the Taskbar Notification Area that will display a ToolTip of your choice when the mouse is rested over it, will restore the application when clicked, and will display a popup menu when right-clicked. This is all possible because of Visual Basic's ability to directly handle callbacks, therefore taking full advantage of the Shell_NotifyIcon function that is exported by Shell32.dll.

More Information

The following example can be added to any Visual Basic Project that has at least one form and a standard module.

Step-by-Step Example

  1. Add the following code to the declarations section of a standard module in your project:
          'user defined type required by Shell_NotifyIcon API call
    Public Type NOTIFYICONDATA
    cbSize As Long
    hwnd As Long
    uId As Long
    uFlags As Long
    uCallBackMessage As Long
    hIcon As Long
    szTip As String * 64
    End Type

    'constants required by Shell_NotifyIcon API call:
    Public Const NIM_ADD = &H0
    Public Const NIM_MODIFY = &H1
    Public Const NIM_DELETE = &H2
    Public Const NIF_MESSAGE = &H1
    Public Const NIF_ICON = &H2
    Public Const NIF_TIP = &H4
    Public Const WM_MOUSEMOVE = &H200
    Public Const WM_LBUTTONDOWN = &H201 'Button down
    Public Const WM_LBUTTONUP = &H202 'Button up
    Public Const WM_LBUTTONDBLCLK = &H203 'Double-click
    Public Const WM_RBUTTONDOWN = &H204 'Button down
    Public Const WM_RBUTTONUP = &H205 'Button up
    Public Const WM_RBUTTONDBLCLK = &H206 'Double-click

    Public Declare Function SetForegroundWindow Lib "user32" _
    (ByVal hwnd As Long) As Long
    Public Declare Function Shell_NotifyIcon Lib "shell32" _
    Alias "Shell_NotifyIconA" _
    (ByVal dwMessage As Long, pnid As NOTIFYICONDATA) As Boolean

    Public nid As NOTIFYICONDATA
  2. Add the following code to any form in your project that you want to respond to the System Tray Icon, or Notification Icon, for your application:
          Private Sub Form_Load()
    'the form must be fully visible before calling Shell_NotifyIcon
    Me.Show
    Me.Refresh
    With nid
    .cbSize = Len(nid)
    .hwnd = Me.hwnd
    .uId = vbNull
    .uFlags = NIF_ICON Or NIF_TIP Or NIF_MESSAGE
    .uCallBackMessage = WM_MOUSEMOVE
    .hIcon = Me.Icon
    .szTip = "Your ToolTip" & vbNullChar
    End With
    Shell_NotifyIcon NIM_ADD, nid
    End Sub

    Private Sub Form_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
    'this procedure receives the callbacks from the System Tray icon.
    Dim Result As Long
    Dim msg As Long
    'the value of X will vary depending upon the scalemode setting
    If Me.ScaleMode = vbPixels Then
    msg = X
    Else
    msg = X / Screen.TwipsPerPixelX
    End If
    Select Case msg
    Case WM_LBUTTONUP '514 restore form window
    Me.WindowState = vbNormal
    Result = SetForegroundWindow(Me.hwnd)
    Me.Show
    Case WM_LBUTTONDBLCLK '515 restore form window
    Me.WindowState = vbNormal
    Result = SetForegroundWindow(Me.hwnd)
    Me.Show
    Case WM_RBUTTONUP '517 display popup menu
    Result = SetForegroundWindow(Me.hwnd)
    Me.PopupMenu Me.mPopupSys
    End Select
    End Sub

    Private Sub Form_Resize()
    'this is necessary to assure that the minimized window is hidden
    If Me.WindowState = vbMinimized Then Me.Hide
    End Sub

    Private Sub Form_Unload(Cancel As Integer)
    'this removes the icon from the system tray
    Shell_NotifyIcon NIM_DELETE, nid
    End Sub

    Private Sub mPopExit_Click()
    'called when user clicks the popup menu Exit command
    Unload Me
    End Sub

    Private Sub mPopRestore_Click()
    'called when the user clicks the popup menu Restore command
    Dim Result As Long
    Me.WindowState = vbNormal
    Result = SetForegroundWindow(Me.hwnd)
    Me.Show
    End Sub
  3. Make the following Property Settings on the same form to which you added the above code:

    Property Required Setting for Taskbar Notification Area example
    -----------------------------------------------------------------------
    Icon = The icon you want to appear in the system tray.
    Minbutton = True
    ShownInTaskbar = False
  4. Add the following Menu items to the same form using the Menu Editor:

    Caption Name Enabled Visible Position
    ---------------------------------------------------------
    &SysTray mPopupSys True False Main Level
    &Restore mPopRestore True True Inset one
    &Exit mPopExit True True Inset one
You can add additional menu items as needed.

Taskbar Notification Area Flexibility

You can modify the ToolTip that appears over the Notification icon by changing the following line in the Form_Load procedure:
   .szTip = "Your ToolTip" & vbNullChar
Replace "Your ToolTip" with the text that you want to appear.

You can modify the Icon that appears in the Taskbar Notification Area by changing the following line in the Form_Load procedure:
   .hIcon = Me.Icon
Replace Me.Icon with any Icon in your project.

You can change any of the Taskbar Notification Area settings at any time after the use of the NIM_ADD constant by reassigning the values in the nid variable and then using the following variation of the Shell_NotifyIcon API call:
   Shell_NotifyIcon NIM_MODIFY, nid.
However, if you want a different form to receive the callback, then you will need to delete the current icon first using "Shell_NotifyIcon NIM_Delete, nid" as the NIM_Modify function will not accept a new Hwnd, or you will need to add another Icon to the systray for the new form using "Shell_NotifyIcon NIM_ADD, nid" after refilling the nid type with the new forms Hwnd. You can also declare separate copies of the nid type for each form that you want to display an icon for in the Windows System Tray and change them in each form's activate event using the NIM_DELETE and NIM_ADD sequence.

References

For more information regarding using the System Tray or using the Taskbar Notification Area from Visual Basic 4.0 or earlier, click the following article number to view the article in the Microsoft Knowledge Base:

149276 How to use icons with the Windows 95/98/Me Taskbar Notification Area

Vlastnosti

ID článku: 176085 - Poslední kontrola: 4. 8. 2008 - Revize: 1

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