很多朋友都见到过能在托盘图标上出现气球提示的软件，不说软件，就是在“磁盘空间不足”时Windows给出的提示就属于气球提示，那么怎样在自己的程序中添加这样的气球提示呢？

其实并不难，关键就在添加托盘图标时所使用的NOTIFYICONDATA结构，源代码如下：

窗体模块：

Option Explicit

Private Declare Function Shell_NotifyIcon Lib "shell32.dll" Alias "Shell_NotifyIconA" (ByVal dwMessage As Long, lpData As NOTIFYICONDATA) As Long

Private Type NOTIFYICONDATA
cbSize As Long ' 结构大小(字节)
hwnd As Long ' 处理消息的窗口的句柄
uId As Long ' 唯一的标识符
uFlags As Long ' Flags
uCallBackMessage As Long ' 处理消息的窗口接收的消息
hIcon As Long ' 托盘图标句柄
szTip As String * 128 ' Tooltip 提示文本
dwState As Long ' 托盘图标状态
dwStateMask As Long ' 状态掩码
szInfo As String * 256 ' 气球提示文本
uTimeoutOrVersion As Long ' 气球提示消失时间或版本
' uTimeout - 气球提示消失时间(单位:ms, 10000 -- 30000)
' uVersion - 版本(0 for V4, 3 for V5)
szInfoTitle As String * 64 ' 气球提示标题
dwInfoFlags As Long ' 气球提示图标
End Type

' dwState to NOTIFYICONDATA structure
Private Const NIS_HIDDEN = &H1 ' 隐藏图标
Private Const NIS_SHAREDICON = &H2 ' 共享图标

' dwInfoFlags to NOTIFIICONDATA structure
Private Const NIIF_NONE = &H0 ' 无图标
Private Const NIIF_INFO = &H1 ' "消息"图标
Private Const NIIF_WARNING = &H2 ' "警告"图标
Private Const NIIF_ERROR = &H3 ' "错误"图标

' uFlags to NOTIFYICONDATA structure
Private Const NIF_ICON As Long = &H2
Private Const NIF_INFO As Long = &H10
Private Const NIF_MESSAGE As Long = &H1
Private Const NIF_STATE As Long = &H8
Private Const NIF_TIP As Long = &H4

' dwMessage to Shell_NotifyIcon
Private Const NIM_ADD As Long = &H0
Private Const NIM_DELETE As Long = &H2
Private Const NIM_MODIFY As Long = &H1
Private Const NIM_SETFOCUS As Long = &H3
Private Const NIM_SETVERSION As Long = &H4

Private Sub Form_Load()
' 向托盘区添加图标
Dim IconData As NOTIFYICONDATA
Dim title As String
title = "托盘程序" & vbNullChar
With IconData
.cbSize = Len(IconData)
.hwnd = Me.hwnd
.uId = 0
.uFlags = NIF_TIP Or NIF_ICON Or NIF_MESSAGE Or NIF_INFO Or NIF_STATE
.uCallBackMessage = WM_NOTIFYICON
.szTip = title
.hIcon = Me.Icon.Handle
.dwState = 0
.dwStateMask = 0
.szInfo = "这是气球提示" & vbNullChar
.szInfoTitle = title
.dwInfoFlags = NIIF_INFO
.uTimeoutOrVersion = 10000
End With
Shell_NotifyIcon NIM_ADD, IconData
preWndProc = SetWindowLong(Me.hwnd, GWL_WNDPROC, AddressOf WindowProc)
End Sub

Private Sub Form_Unload(Cancel As Integer)
' 删除托盘区图标
Dim IconData As NOTIFYICONDATA
With IconData
.cbSize = Len(IconData)
.hwnd = Me.hwnd
.uId = 0
.uFlags = NIF_TIP Or NIF_ICON Or NIF_MESSAGE
.uCallBackMessage = WM_NOTIFYICON
.szTip = "托盘程序"
.hIcon = Me.Icon.Handle
End With
Shell_NotifyIcon NIM_DELETE, IconData
SetWindowLong Me.hwnd, GWL_WNDPROC, preWndProc

' 卸载所有窗体
Dim frm As Form
For Each frm In Forms
Unload frm
Next
End Sub


标准模块：

Option Explicit

Public Declare Func