写过VB的人都知道Msgbox函数弹出系统提示对话框，这个对话框既然是Windows给我们使用的那么我们就可以通过别的方式改变它。
下面我就会调用MessageBox的Api来改变VB的对话框函数，创造出我们自己风格的Msgbox！
该例程是将Msgbox弹出，并且总是位于窗口的中央；而且修改了Msgbox中的“确定”按钮上的文字。程序中简单的使用了Windows的钩子。
1·加入一个模块：
Option Explicit
'--------------------API声明部分--------------------
Private Const WH_CBT = 5
Private Const HCBT_ACTIVATE = 5
Private Type RECT
Left As Long
Top As Long
Right As Long
Bottom As Long
End Type
'使用API的MessageBox替代VB系统的MsgBox
Private Declare Function MessageBox Lib "user32" _
Alias "MessageBoxA" _
(ByVal hWnd As Long, _
ByVal lpText As String, _
ByVal lpCaption As String, _
ByVal wType As Long) As Long
Private Declare Function SetWindowsHookEx Lib "user32" _
Alias "SetWindowsHookExA" _
(ByVal idHook As Long, _
ByVal lpfn As Long, _
ByVal hmod As Long, _
ByVal dwThreadId As Long) As Long
Private Declare Function UnhookWindowsHookEx Lib "user32" _
(ByVal hHook As Long) As Long
Private Declare Function MoveWindow Lib "user32" _
(ByVal hWnd As Long, _
ByVal X As Long, _
ByVal Y As Long, _
ByVal nWidth As Long, _
ByVal nHeight As Long, _
ByVal bRepaint As Long) As Long
Private Declare Function GetWindowRect Lib "user32" _
(ByVal hWnd As Long, _
lpRect As RECT) As Long
Public Declare Function GetDlgItem Lib "user32" _
(ByVal hDlg As Long, ByVal nIDDlgItem As Long) As Long
Private Declare Function SetDlgItemText Lib "user32" Alias "SetDlgItemTextA" _
(ByVal hDlg As Long, ByVal nIDDlgItem As Long, ByVal lpString As String) As Long
Private Declare Function GetDlgItemText Lib "user32" Alias "GetDlgItemTextA" _
(ByVal hDlg As Long, ByVal nIDDlgItem As Long, ByVal lpString As String, ByVal nMaxCount As Long) As Long
Private hHook As Long
Private Const IDOK = 1
Private Const IDCANCEL = 2
Private Const IDABORT = 3
Private Const IDRETRY = 4
Private Const IDIGNORE = 5
Private Const IDYES = 6
Private Const IDNO = 7
Private Const IDPROMPT = &HFFFF&
'----------------------窗体句柄----------------------'
Private hFormhWnd As Long
'''''''''''''''''''''''''''''''''''''''''''''''''''''
'替代VB中的Msgbox函数
'''''''''''''''''''''''''''''''''''''''''''''''''''''
Public Function Msgbox(hWnd As Long, sPrompt As String, _
Optional dwStyle As Long, _
Optional sTitle As String) As Long
Dim hInstance As Long
Dim hThreadId As Long
hInstance = App.hInstance
hThreadId = App.ThreadID
If dwStyle = 0 Then dwStyle = vbOKOnly
If Len(sTitle) = 0 Then sTitle = App.EXEName
'将当前窗口的句柄付给变量
hFormhWnd = hWnd
'设置钩子
hHook = SetWindowsHookEx(WH_CBT, _
AddressOf CBTProc, _
hInstance, hThreadId)
'调用MessageBox API
Msgbox = MessageBox(hWnd, sPrompt, sTitle, dwStyle)
End Function
'''''''''''''''''''''''''''''''''''''''''''''''''''''
'HOOK处理
'''''''''''''''''''''''''''''''''''''''''''''''''''''
Public Function CBTProc(ByVal nCode As Long, _
ByVal wParam As Long, _
ByVal lParam As Long) As Long
'变量声明
Dim rc As RECT
Dim rcFrm As RECT
Dim newLeft As Long
Dim newTop As Long
Dim dlgWidth As Long
Dim dlgHeight As Long
Dim scrWidth As Long
Dim scrHeight As Long
Dim frmLeft As Long
Dim frmTop As Long
Dim frmWidth As Long
Dim frmHeight As Long
Dim hwndMsgBox As Long
' Dim lngHwnd As Long
'当MessageBox出现时，将Msgbox对话框居中与所在的窗口
If nCode = HCBT_ACTIVATE Then
'消息为HCBT_ACTIVATE时，参数wParam包含的是MessageBox的句柄
hwndMsgBox = wParam
'得到MessageBox对话框的Rect
Call GetWindowRect(hwndMsgBox, rc)
Call GetWindowRect(hFormhWnd, rcFrm)
'使MessageBox居中
frmLeft = rcFrm.Left
frmTop = rcFrm.Top
frmWidth = rcFrm.Right - rcFrm.Left
frmHeight = rcFrm.Bottom - rcFrm.Top
dlgWidth = rc.Right - rc.Left
dlgHeight = rc.Bottom - rc.Top
scrWidth = Screen.Width \ Screen.TwipsPerPixelX
scrHeight = Screen.Height \ Screen.TwipsPerPixelY
newLeft = frmLeft + ((frmWidth - dlgWidth) \ 2)
newTop = frmTop + ((frmHeight - dlgHeight) \ 2)
'修改确定按钮的文字
Call SetDlgItemText(hwndMsgBox, IDOK, "这是确定按钮")
'Msgbox居中
Call MoveWindow(hwndMsgBox, newLeft, newTop, dlgWidth, dlgHeight, True)
'卸载钩子
UnhookWindowsHookEx hHook
End If
CBTProc = False
End Function
2·窗体中的代码：
Form1中的-----
Option Explicit
Private Sub Command1_Click()
'变量声明
Dim strTitle As String
Dim strPrompt As String
Dim lngStyle As Long
'MessageBox的标题
strTitle = "我的应用"
'MessageBox的内容
strPrompt = "这是 hook MessageBox 的演示" & vbCrLf & vbCrLf & _
"MessageBox的对话框将会居中在Form中"
'MessageBox样式
lngStyle = vbAbortRetryIgnore Or vbInformation
Select Case Msgbox(hWnd, strPrompt, lngStyle, strTitle)
Case vbRetry: Text1.Text = "Retry button 按下"
Case vbAbort: Text1.Text = "Abort button 按下"
Case vbIgnore: Text1.Text = "Ignore button 按下"
End Select
End Sub
Private Sub Command2_Click()
Form2.Show
End Sub
Form2中的-----
Option Explicit
Private Sub Command1_Click()
Call Msgbox(Me.hWnd, "确定按钮展示！", 0, "")
End Sub
