How to close a message box using code?

[rbnwares]

I have a problem. When I use a particular activeX a msgbox always appear. Can I close the msgbox by code? Any kind of help is appreciated.

[crispin]

If you created the message box yourself then its difficult but possible. See http://www.mvps.org/vbvision and look in the code samples.
If you didn't create the message box then it's going to be very complex...

[Jop]

Actually it's not that easy as just closing it, because the MsgBox is Modal for your program (in other words, you can't do anything with your prog until the MsgBox is closed )

But I wrote this Sub that closes the MsgBox:

Option Explicit
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Declare Function CreateThread Lib "kernel32" (lpThreadAttributes As Any, ByVal dwStackSize As Long, ByVal lpStartAddress As Long, lpParameter As Any, ByVal dwCreationFlags As Long, lpThreadID As Long) As Long
Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Const WM_CLOSE = &H10
Public Sub CloseBox()
Dim BoxH&
   BoxH = FindWindow(vbNullString, "CLOSEME") 'find the handle of the msgbox
   PostMessage BoxH, WM_CLOSE, 0&, 0& 'Close it!
End Sub

You could put it in a another program and shell it, but that would be real weak , so now the actual trick is to create another ASynchronous thread, so it can be executed while the MsgBox is open

I wrote this code for ya, put it in a form.

Private hThread As Long, hThreadID As Long

Private Sub Form_Activate()
    hThread = CreateThread(ByVal 0&, ByVal 0&, AddressOf CloseBox, ByVal 0&, ByVal 0&, hThreadID) 'create the thread

'show the msgbox (with the caption CLOSEME, that's important
'because you find the window by the caption (in this case))
MsgBox "hey", , "CLOSEME" 

End Sub


Private Sub Form_Unload(Cancel As Integer)
    CloseHandle hThread 'Close the thread
End Sub

Cool huh

[SargumSingh]

Jop, What is "AddressOf CloseBox" argument?
Thanks!

[Jop]

It gets the Memory Adress of the Callback routine we're calling (CloseBox)

[SargumSingh]

I tried to do it. It would close any other app with 'CLOSEME' caption but couldn't close the message box from the same app. Could you please let me know what could I be missing? Or send me a sample app. My e-mail is
[email protected]
Thanks a bunch!

[crispin]

I can't distribute the source as it's not mine, but heres the link to Brian Staffords site (VB God) BTW: this code is fairly complex.

http://www.mvps.org/vbvision/_sample...geBox_Demo.zip

[Jop]

Look, it finds the window by it's caption, in the case of the Example it's CLOSEME, now when you want to change the caption, be sure to change it in the Sub CloseBox (in the module) too.

And the code in the Form is very important because it starts a new thread, so VB can close the msgbox (usally when you open a MsgBox, the program is paused until you close the box)

Now let's say you want a MsgBox with the caption Are You Sure?

in the form you would type

Private hThread As Long, hThreadID As Long

Private Sub Form_Activate()
    hThread = CreateThread(ByVal 0&, ByVal 0&, AddressOf CloseBox, ByVal 0&, ByVal 0&, hThreadID) 'create the thread

'show the msgbox (with the caption Are You Sure?, that's important
'because you find the window by the caption (in this case))
MsgBox "hey", , "Are You Sure?" 

End Sub


Private Sub Form_Unload(Cancel As Integer)
    CloseHandle hThread 'Close the thread
End Sub

and in the module

Option Explicit
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Declare Function CreateThread Lib "kernel32" (lpThreadAttributes As Any, ByVal dwStackSize As Long, ByVal lpStartAddress As Long, lpParameter As Any, ByVal dwCreationFlags As Long, lpThreadID As Long) As Long
Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Const WM_CLOSE = &H10
Public Sub CloseBox()
Dim BoxH&
   BoxH = FindWindow(vbNullString, "Are You Sure?") 'find the handle of the msgbox
   PostMessage BoxH, WM_CLOSE, 0&, 0& 'Close it!
End Sub

Hope it helps