重点为：向系统注册“TaskbarCreated”消息

Public Function Wndproc(ByVal hwnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
If Msg = lngMsgBarRester Then '重建托盘图标
FrmMain.cTray.InTray = False
FrmMain.cTray.InTray = True
End If
'交还控制权给系统继续监测热键
Wndproc = CallWindowProc(preWinProc, hwnd, Msg, wParam, lParam)
End Function

Sub Main()
lngMsgBarRester = RegisterWindowMessage("TaskBarCreated") '注册任务栏创建的消息
End Sub

例子1：
Dim aa(10) As String
Dim bb
Dim i As Integer
For i = 0 To 9
aa(i) = "aa" + Str(i)
Next
bb = Filter(aa, "aa")
Label1.Caption = bb(0)
Label2.Caption = bb(1)
Label3.Caption = bb(2)
'这时Label1显示aa 0,Label2显示aa 1,Label3显示aa 2。bb我也不知设为什么类型，所以就没设定。

例子2：
Dim b() As String
Dim a(10) As String
Dim i As Integer
For i = 0 To 10
a(i) = Trim(Str(i))
Next i
a(1) = "5"
b = Filter(a, "5")
MsgBox UBound(b, 1)
b = Filter(a, "5") '就是将A数组中所有="5"的项附给B数组

例子3：
'用Filter函数取出有可能与所选项重复的值
'NewArray和MatchArray都是数组，一般用在数组的筛选上！
MatchArray = Filter(NewArray, orgArray(i), True, vbTextCompare)

'任务栏高度[此部分相关代码转载自 枕善居]
Private Declare Function SystemParametersInfo Lib "user32" Alias "SystemParametersInfoA" (ByVal uAction As Long, ByVal uParam As Long, ByRef lpvParam As Any, ByVal fuWinIni As Long) As Long
Private Const SPI_GETWORKAREA = 48

Private Type RECT
Left As Long
Top As Long
Right As Long
Bottom As Long
End Type

'透明
Private Declare Function SetLayeredWindowAttributes Lib "user32" (ByVal hWnd As Long, ByVal crKey As Long, ByVal bAlpha As Byte, ByVal dwFlags As Long) As Long
Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long) As Long
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Const WS_EX_LAYERED = &H80000
Const GWL_EXSTYLE = (-20)
Const LWA_ALPHA = &H2
Const LWA_COLORKEY = &H1

'延迟
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)

'最前
Private Declare Function SetWindowPos Lib "user32" (ByVal hWnd As Long, ByVal hWndInsertAfter As Long, ByVal x As Long, ByVal y As Long, ByVal cx As Long, ByVal cy As Long, ByVal wFlags As Long) As Long
Private Const HWND_BOTTOM = 1
Private Const HWND_BROADCAST = &HFFFF&
Private Const HWND_DESKTOP = 0
Private Const HWND_NOTOPMOST = -2
Private Const HWND_TOP = 0
Private Const HWND_TOPMOST = -1

'可见区域
Private Declare Function CreateRectRgn Lib "gdi32" (ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Private Declare Function SetWindowRgn Lib "user32" (ByVal hWnd As Long, ByVal hRgn As Long, ByVal bRedraw As Boolean) As Long
Private Declare Function DeleteObject Lib "gdi32" (ByVal hObject As Long<
/font>) As Long

Dim MyRect As Long
Dim MyRgn As Long

Dim X1 As Integer, Y1 As Integer
Dim X2 As Integer, Y2 As Integer
Dim OpenSpeed As Integer
Dim CloseSpeed As Integer

Dim WiteLong As Integer


Private Sub Form_Load()
'------------------------------------------------------------------
OpenSpeed = 10 '出现时速度
CloseSpeed = 10 '关闭时淡出的速度
Timer1.Interval = 10 '出现时显示平滑度
WiteLong = 30 '关闭前等待时间(秒),为0则不会自动关闭
'------------------------------------------------------------------

'计算任务栏高
Dim lRes As Long
Dim rectVal As RECT
Dim TaskbarHeight As Integer

lRes = SystemParametersInfo(SPI_GETWORKAREA, 0, rectVal, 0)
TaskbarHeight = Screen.Height - rectVal.Bottom * Screen.TwipsPerPixelY

'确定位置
Me.Move Screen.Width * 0.75, Screen.Height * 0.75 - TaskbarHeight, _
Screen.Width \ 4, Screen.Height \ 4

'永在最前
SetWindowPos Me.hWnd, HWND_TOPMOST, Me.Left \ Screen.TwipsPerPixelX, Me.Top \ Screen.TwipsPerPixelY, Me.Width, Me.Height, 1

'为遮蔽窗体计算坐标
X1 = 0
Y1 = Me.Width \ Screen.TwipsPerPixelX

X2 = Me.Width \ Screen.TwipsPerPixelX
Y2 = Me.Height \ Screen.TwipsPerPixelY - 1

'遮蔽部分窗体为不可见
MyRect = CreateRectRgn(X1, Y1, X2, Y2)
MyRgn = SetWindowRgn(Me.hWnd, MyRect, True)
End Sub

Private Sub Form_Unload(Cancel As Integer)
Call CloseMe(1) '以什么样的方式关闭自己，有 1-淡出 和 2-收缩 可选
Call DeleteObject(MyRect)
End Sub


Private Sub Timer1_Timer()
Y2 = Y2 - OpenSpeed

If Y2 <= 0 Then
MyRect = CreateRectRgn(0, 0, Me.Width \ Screen.TwipsPerPixelX, Y2)
MyRgn = SetWindowRgn(Me.hWnd, MyRect, True)

Timer1.Enabled = False

'----------------------
If WiteLong <> 0 Then
Timer2.Interval = 1000
Timer2.Enabled = True
End If
End If

MyRect = CreateRectRgn(X1, Y1, X2, Y2)
MyRgn = SetWindowRgn(Me.hWnd, MyRect, True)
End Sub

Private Sub Timer2_Timer()
Static NL As Integer
NL = NL + 1

If NL >= WiteLong Then Unload Me

End Sub


'==============================================
'0 - 不使用卸载效果
'1 - 使用透明淡出效果
'2 - 使用收缩效果
'==============================================
Private Sub CloseMe(Optional N As Integer = 1)
Select Case N
Case 0
Exit Sub
Case 1
Dim rtn As Long

rtn = GetWindowLong(Me.hWnd, GWL_EXSTYLE)
rtn = rtn Or WS_EX_LAYERED
SetWindowLong Me.hWnd, GWL_EXSTYLE, rtn

For I = 255 To 10 Step -10
SetLayeredWindowAttributes Me.hWnd, 0, I, LWA_ALPHA
DoEvents
Sleep CloseSpeed
Next I
Case 2
While Y2 < (Me.Height / Screen.TwipsPerPixelY)
Y2 = Y2 + OpenSpeed
MyRect = CreateRectRgn(X1, Y1, X2, Y2)
MyRgn = SetWindowRgn(Me.hWnd, MyRect, True)
Sleep OpenSpeed
Wend
Case Else

End Select
End Sub

'#############################
'**
'** 文件 frmDownLoad.frm 的内容
'**
'#############################
VERSION 5.00
Begin VB.Form frmDownLoad
BorderStyle = 1 'Fixed Single
Caption = "Form1"
ClientHeight = 2880
ClientLeft = 45
ClientTop = 330
ClientWidth = 6375
BeginProperty Font
Name = "宋体"
Size = 9
Charset = 0
Weight = 400
Underline = 0 'False
Italic = 0 'False
Strikethrough = 0 'False
EndProperty
LinkTopic = "文件下载"
MaxButton = 0 'False
ScaleHeight = 2880
ScaleWidth = 6375
StartUpPosition = 2 'CenterScreen
Begin VB.CommandButton cmdStop
Caption = "停止"
Enabled = 0 'False
Height = 480
Left = 1860
TabIndex = 6
Top = 2160
Width = 1365
End
Begin VB.CommandButton cmdStart
Caption = "开始"
Height = 480
Left = 165
TabIndex = 5
Top = 2160
Width = 1365
End
Begin VB.TextBox txtFile
Height = 330
Left = 750
TabIndex = 3
Top = 705
Width = 5445
End
Begin VB.TextBox txtURL
Height = 330
Left = 750
TabIndex = 1
Top = 285
Width = 5445
End
Begin VB.Label lblCount
BackStyle = 0 'Transparent
Caption = "下载"
Height = 180
Left = 180
TabIndex = 4
Top = 1245
Width = 5130
End
Begin VB.Label Label1
AutoSize = -1 'True
Caption = "文件:"
Height = 180
Left = 195
TabIndex = 2
Top = 780
Width = 450
End
Begin VB.Label lblURL
AutoSize = -1 'True
Caption = "URL:"
Height = 180
Left = 195
TabIndex = 0
Top = 360
Width = 360
End
End
Attribute VB_Name = "frmDownLoad"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Option Explicit

Private Declare Function StrFormatByteSize Lib "shlwapi" Alias _
"StrFormatByteSizeA" (ByVal dw As Long, ByVal pszBuf As String, ByRef _
cchBuf As Long nt color="#000000">) As String

Private Declare Function InternetOpen Lib "wininet.dll" _
Alias "InternetOpenA" (ByVal sAgent As String, _
ByVal lAccessType As Long, ByVal sProxyName As String, _
ByVal sProxyBypass As String, ByVal lFlags As Long) As Long
Private Declare Function InternetOpenUrl Lib "wininet.dll" _
Alias "InternetOpenUrlA" (ByVal hOpen As Long, _
ByVal surl As String, ByVal sHeaders As String, _
ByVal lLength As Long, ByVal lFlags As Long, _
ByVal lContext As Long) As Long

Private Declare Function HttpOpenRequest Lib "wininet.dll" _
Alias "HttpOpenRequestA" _
(ByVal hInternetSession As Long, _
ByVal lpszVerb As String, _
ByVal lpszObjectName As String, _
ByVal lpszVersion As String, _
ByVal lpszReferer As String, _
ByVal lpszAcceptTypes As Long, _
ByVal dwFlags As Long, _
ByVal dwContext As Long) As Long
Private Declare Function InternetConnect Lib "wininet.dll" _
Alias "InternetConnectA" _
(ByVal hInternetSession As Long, _
ByVal lpszServerName As String, _
ByVal nProxyPort As Integer, _
ByVal lpszUsername As String, _
ByVal lpszPassword As String, _
ByVal dwService As Long, _
ByVal dwFlags As Long, _
ByVal dwContext As Long) As Long
Private Declare Function HttpSendRequest Lib "wininet.dll" _
Alias "HttpSendRequestA" _
(ByVal hHttpRequest As Long, _
ByVal sHeaders As String, _
ByVal lHeadersLength As Long, _
ByVal sOptional As String, _
ByVal lOptionalLength As Long) As Boolean

Private Declare Function InternetReadFile Lib "wininet.dll" _
(ByVal hFile As Long, ByRef sBuffer As Byte, _
ByVal lNumBytesToRead As Long, lNumberOfBytesRead As Long) _
As Integer
Private Declare Function InternetCloseHandle Lib "wininet.dll" _
(ByVal hInet As Long) As Integer

Private Declare Function GetLastError Lib "kernel32" () As Long

' Adds one or more HTTP request headers to the HTTP request handle.
'Public Declare Function HttpAddRequestHeaders Lib "wininet.dll" Ali
as "HttpAddRequestHeadersA" _
'(ByVal hHttpRequest As Long, ByVal sHeaders As String, ByVal lHeadersLength As Long, _
'ByVal lModifiers As Long) As Integer
Private bolStop As Boolean
' 然后，我们可以得到包含了一份详细说明的URL文本文件，它显示在下面的函数中：
Public Function DownloadFile(ByVal surl As String, ByVal strFile As String) As Long
Dim s As String
Dim hOpen As Long
Dim hOpenUrl As Long
Dim bDoLoop As Boolean
Dim bRet As Boolean
Dim intFH As Integer

Dim sReadBuffer() As Byte
Dim lNumberOfBytesRead As Long
Dim lCount As Long
Dim myCount As New clsCount
Const INTERNET_OPEN_TYPE_PRECONFIG = 0
Const INTERNET_OPEN_TYPE_DIRECT = 1
Const INTERNET_OPEN_TYPE_PROXY = 3
Const scUserAgent = "VB OpenUrl"
Const INTERNET_FLAG_RELOAD = &H80000000

lblCount.Caption = "正在连接服务器..."
lblCount.Refresh
hOpen = InternetOpen(scUserAgent, INTERNET_OPEN_TYPE_PRECONFIG, vbNullString, vbNullString, 0)
hOpenUrl = InternetOpenUrl(hOpen, surl, vbNullString, 0, INTERNET_FLAG_RELOAD, 0)
lCount = 0

If hOpen <> 0 And hOpenUrl <> 0 Then
intFH = FreeFile
If Dir(strFile) <> "" Then
VBA.FileSystem.Kill strFile
End If
Open strFile For Binary As #intFH
myCount.Clear
Do While True
ReDim sReadBuffer(2048)
bRet = InternetReadFile(hOpenUrl, sReadBuffer(0), 2048, lNumberOfBytesRead)
If lNumberOfBytesRead > 0 And bRet = True Then
'if lnumberofbytesread<>2048 then
ReDim Preserve sReadBuffer(0 To lNumberOfBytesRead - 1)
Put #intFH, , sReadBuffer
'
' buf.AddRange sReadBuffer, 0, lNumberOfBytesRead - 1
lCount = lCount + lNumberOfBytesRead
myCount.Count lNumberOfBytesRead
lblCount.Caption = "已下载 " & VBStrFormatByteSize(lCount) & " [ " & VBStrFormatByteSize(myCount.Speed) & " /秒 ]"
lblCount.Refresh
Else
Exit Do
End If
bolStop = False
DoEvents
If bolStop = True Then
Exit Do
End If
Loop
Close #intFH
lblCount.Caption = "共下载 " & lCount & " 字节"
Else
lblCount.Caption = "打开URL错误"
End If

If hOpenUrl <> 0 Then InternetCloseHandle (hOpenUrl)
If hOpen <> 0 Then InternetCloseHandle (hOpen)
Set myCount = Nothing
DownloadFile = lCount
End Function
Private Sub cmdStart_Click()
txtURL.Enabled = False
txtFile.Enabled = False
cmdStart.Enabled = False
cmdStop.Enabled = True
DownloadFile txtURL.Text, txtFile.Text
cmdStop.Enabled = False
cmdStart.Enabled = True
txtFile.Enabled = True
txtURL.Enabled = True

End Sub
Private Sub cmdStop_Click()
bolStop = True
End Sub
Private Sub SetText(ByVal txt As TextBox)
txt.Text = GetSetting(App.Title, Me.Name,
txt.Name)
End Sub
Private Sub SaveText(ByVal txt As TextBox)
SaveSetting App.Title, Me.Name, txt.Name, txt.Text
End Sub
Private Sub Form_Load()
SetText Me.txtFile
SetText Me.txtURL
End Sub
Private Sub Form_Unload(Cancel As Integer)
SaveText Me.txtFile
SaveText Me.txtURL
End Sub

Private Function VBStrFormatByteSize(ByVal lngSize As Long) As String
Dim strSize As String * 128
Dim strData As String
Dim lPos As Long
StrFormatByteSize lngSize, strSize, 128
lPos = InStr(1, strSize, Chr$(0))
strData = Left$(strSize, lPos - 1)
If lngSize > 1024 Then
strData = lngSize & "字节(" & strData & ")"
End If
VBStrFormatByteSize = strData
End Function

'########################
'**
'** 文件 clsCount.cls 的内容
'**
'########################
VERSION 1.0 CLASS
BEGIN
MultiUse = -1 'True
Persistable = 0 'NotPersistable
DataBindingBehavior = 0 'vbNone
DataSourceBehavior = 0 'vbNone
MTSTransactionMode = 0 'NotAnMTSObject
END
Attribute VB_Name = "clsCount"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Option Explicit
'******************************************************************************
'**
'** 用于计算速度的类模块
'**
'** 该类模块设定一个计数器,由程序不断的累计数据,并根据所花时间计算数据
'**
'** 编制: 袁永福
'** 时间: 2002-4-2
'**
'******************************************************************************
Private Declare Function GetTickCount Lib "kernel32" () As Long

Private lngCountStart As Long
Private lngCountCurrent As Long
Private lngCountLast As Long
Private lngSpeed As Long
Private lngTickStart As Long
Private lngTickCurrent As Long
Private lngTickLast As Long
'Public StopCount As Boolean
'** 获得计数数据 **************************************************************
'** 累计初始值
Public Property Get CountStart() As Long
CountStart = lngCountStart
End Property
'** 累计终止值
Public Property Get CountEnd() As Long
CountEnd = lngCountCurrent
End Property
'** 累计总的速度
Public Property Get TotalSpeed() As Long
If lngTickCurrent = lngTickStart Then
TotalSpeed = 0
Else
TotalSpeed = (lngCountCurrent - lngCountStart) / ((lngTickCurrent - lngTickStart) / 1000)
End If
End Property
'** 累计所花毫秒数
Public Property Get TotalTickCount() As Long
TotalTickCount = lngTickCurrent - lngTickStart
End Property
'** 清除所有数据 **************************************************************
Public Sub Clear()
lngCountStart = 0
lngCountCurrent = 0
lngCountLast = 0

lngSpeed = 0

lngTickStart = GetTickCount()
lngTickCurrent = lngTickStart
lngTickLast = lngTickStart

'StopCount = False
End Sub
'** 设置累计基数
Public Property Let CountStart(ByVal lStart As Long)
lngCountStart = lStart
lngCountCurrent = lStart
End Property
'** 累加数据 **
Public Sub Count(Optional ByVal lCount As Long = 1)
lngCountCurrent = lngCountCurrent + lCount
lngTickCurrent = GetTickCount()
End Sub

'** 获得速度 **
Public Property Get Speed() As Long
'lngTickCurrent = GetTickCount()
If lngTickLast = lngTickCurrent Then
Speed = lngSpeed
Else
Speed = (lngCountCurrent - lngCountLast) / ((lngTickCurrent - lngTickLast) / 1000)
lngSpeed = Speed
lngTickLast = lngTickCurrent
lngCountLast = lngCountCurrent
End If
End Property

'** 数据是否是最新更新的 **
Public Property Get NewSpeed() As Boolean
Dim bolNew As Boolean
If lngTickCurrent > lngTickLast + 1000 Then
bolNew = True
Else
bolNew = False
End If
NewSpeed = bolNew
End Property

【方法一】

StrComp(string1, String2, [Compare])

'函数功能：比较字符串string1和string2。

'返回说明：返回整数值：当string1string2时，返回值>0。这种比较是按照字符的字典序进行比较。

【方法二】

Declare Function lstrcmp Lib "kernel32" Alias "lstrcmpA" (ByVal lpString1 As String, ByVal lpString2 As String) As Long

'或者用API的lstrcmp也能很快地实现字符串的对比

【方法三】

'By JiaJia 2008-05-30
Private Function MyStrCmp(str1 As String, str2 As String) As String
Dim TmpFor As Long, Log As Long
Dim Len1 As Long, Len2 As Long
If Len1 <> Len2 Then '长度不等直接退出
If Instr(str1, str2) > 0 Or Instr(str2, str1) > 0 Then
MyStrCmp = "长度不同，有匹配字符存在。"
Else
MyStrCmp = "完全不同。"
End If
Exit Function
ElseIf Len1 = Len2 Then
For TmpFor = 1 To Len1
If Mid(str1, TmpFor, 1) <> Mid(str2, TmpFor, 1) Then Log = Log + 1
Next
If Log = 0 Then
MyStrCmp = "长度相同，有 " & Log & " 个字符不同。"
Else
MyStrCmp = "完全相同。"
End If
Exit Function
End If
End Function

'窗体代码
Private Sub Form_Load()
HookMouse Me.hwnd
End Sub

Private Sub Form_Unload(Cancel As Integer)
UnHookMouse Me.hwnd
End Sub

'模块代码
'***********************************************************
'mMouseWheel
'鼠标滚轮的事件检测
'***********************************************************
Option Explicit

Private Declare Function CallWindowProc Lib "User32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Private Declare Function SetWindowLong Lib "User32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long

Private Const GWL_WNDPROC = -4
Private Const WM_MOUSEWHEEL = &H20A

Global lpPrevWndProcA As Long

Public bMouseFlag As Boolean '鼠标事件激活标志

Public Sub HookMouse(ByVal hwnd As Long)
lpPrevWndProcA = SetWindowLong(hwnd, GWL_WNDPROC, AddressOf WindowProc)
End Sub

Public Sub UnHookMouse(ByVal hwnd As Long)
SetWindowLong hwnd, GWL_WNDPROC, lpPrevWndProcA
End Sub

Private Function WindowProc(ByVal hw As Long, ByVal uMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Select Case uMsg
Case WM_MOUSEWHEEL '滚动
Dim wzDelta, wKeys As Integer
'wzDelta传递滚轮滚动的快慢，该值小于零表示滚轮向后滚动（朝用户方向），
'大于零表示滚轮向前滚动（朝显示器方向）
wzDelta = HIWORD(wParam)
'wKeys指出是否有CTRL=8、SHIFT=4、鼠标键(左=2、中=16、右=2、附加)按下，允许复合
wKeys = LOWORD(wParam)
'--------------------------------------------------
If wzDelta < 0 Then '朝用户方向
Form1.Cls
Form1.Print "朝用户方向滚"
Else '朝显示器方向
Form1.Cls
Form1.Print "朝显示器方向"
End If
'--------------------------------------------------
Case Else
WindowProc = CallWindowProc(lpPrevWndProcA, hw, uMsg, wParam, lParam)
End Select
End Function

Private Function HIWORD(LongIn As Long) As Integer
HIWORD = (LongIn And &HFFFF0000) \ &H10000 '取出32位值的高16位
End Function
Private Function LOWORD(LongIn As Long) As Integer
LOWORD = LongIn And &HFFFF& '取出32位值的低16位
End Function