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用VB实现窗口图标小化到通知栏

2019/12/05 来源:泰州信息港

导读

如何做到当我们单击窗口的小化按钮时,窗口先小化到任务栏成为按钮,然后消失,图标显示到通知栏呢?大家熟悉的FoxMail能做到,我们也可以

如何做到当我们单击窗口的小化按钮时,窗口先小化到任务栏成为按钮,然后消失,图标显示到通知栏呢?大家熟悉的FoxMail能做到,我们也可以做到。

只要我们能截获小化这个事件发送给窗口的消息,然后换成我们自定义的过程,问题就解决了。大家仔细想一想,当按下小化按纽时会引发什么事件?小化时窗口大小会发生变化会引发Form1.Resize事件,我们只要在Form1.Resize事件里用Form1.Visible = False使窗口消失,然后将窗口图标显示到通知栏即可达到我们想要的效果。

怎样判断发生Resize事件时窗口是小化状态呢?VB里没有现成的做法,我们可以用非富的API函数。API函数库里有一个函数IsIconic(ByVal hwnd As Long),它就是专门判断窗口是否已小化的。这样当Form产生Resize事件时,用IsIconic函数判断一下窗口是否为小化状态,就可知道是否用户按了小化按钮。

关键的一步就是将图标显示在通知栏里,VB里没有现成的做法,我们还得用API函数。API函数库里有一个函数Shell_NotifyIcon(ByVal dwMessage As Long, lpData As NOTIFYICONDATA),是专门操作(包括添加、修改、删除)通知栏里图标的。

点一下通知栏图标,会出现一些诸如"退出"、"显示窗口"的弹出菜单,怎样实现弹出菜单呢?这个很容易实现,因为点击图标会触发图标所在窗口的MouseDown事件,我们把弹出菜单触发过程写入Form1_MouseDown事件即可。具体例程如下:

步、为了增强程序的可移植性,我们新建一个模块,取名为:NoticeIcon,在此模块中定义一些常量、自定义类型、所需的API函数说明及操作通知栏图标的三个自定义函数(添加、修改、删除),模块NoticeIcon具体代码如下所示:

Public Const DefaultIconIndex = 1 '图标缺省索引

Public Const WM_LBUTTONDOWN = &H201 '按鼠标左键

Public Const WM_RBUTTONDOWN = &H204 '按鼠标右键

Public Const NIM_ADD = 0 '添加图标

Public Const NIM_MODIFY = 1 '修改图标

Public Const NIM_DELETE = 2 '删除图标

Public Const NIF_MESSAGE = 1 'message 有效

Public Const NIF_ICON = 2 '图标操作(添加、修改、删除)有效

Public Const NIF_TIP = 4 'ToolTip(提示)有效

'API函数声明

'图标操作

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

'判断窗口是否小化

Declare Function IsIconic Lib "user32" (ByVal hwnd As Long) As Long

'

'设置窗口位置和状态(position)的功能

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

'定义类型

'通知栏图标状态

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

'函数定义

'添加图标至通知栏

Public Function Icon_Add(iHwnd As Long, sTips As String, hIcon As Long, IconID As Long) As Long

'参数说明:iHwnd:窗口句柄,sTips:当鼠标移到通知栏图标上时显示的提示内容

'hIcon:图标句柄,IconID:图标Id号

Dim IconVa As NOTIFYICONDATA

With IconVa

.hwnd = iHwnd

.szTip = sTips + Chr$(0)

.hIcon = hIcon

.uID = IconID

.uCallbackMessage = WM_LBUTTONDOWN

.cbSize = Len(IconVa)

.uFlags = NIF_MESSAGE Or NIF_ICON Or NIF_TIP

Icon_Add = Shell_NotifyIcon(NIM_ADD, IconVa)

End With

End Function

'删除通知栏图标(参数说明同Icon_Add)

Function Icon_Del(iHwnd As Long, lIndex As Long) As Long

Dim IconVa As NOTIFYICONDATA

Dim L As Long

With IconVa

.hwnd = iHwnd

.uID = lIndex

.cbSize = Len(IconVa)

End With

Icon_Del = Shell_NotifyIcon(NIM_DELETE, IconVa)

End Function

'修改通知栏图标(参数说明同Icon_Add)

Public Function Icon_Modify(iHwnd As Long, sTips As String, hIcon As Long, IconID As Long) As Long

Dim IconVa As NOTIFYICONDATA

With IconVa

.hwnd = iHwnd

.szTip = sTips + Chr$(0)

.hIcon = hIcon

.uID = IconID

.uCallbackMessage = WM_LBUTTONDOWN

.cbSize = Len(IconVa)

.uFlags = NIF_MESSAGE Or NIF_ICON Or NIF_TIP

Icon_Modify = Shell_NotifyIcon(NIM_MODIFY, IconVa)

End With

End Function

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