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Tip of the Day
Language: Visual Basic
Expertise: Intermediate
Dec 9, 1998

MessageBox Advantage

You've probably noticed that the display time stops when an application pops up VB's built-in MsgBox. Although the system timer continues to tick, the timer control isn't updated every second, nor do other events (such as painting) process. To update the timer, replace VB's built-in MsgBox with the MessageBox API function. MessageBox-generated dialogs don't stop the timer from updating, and they allow other normal processing, such as form painting:
 
' General Declarations in BAS module
Public 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

' Call from within any form like this:
Call MessageBox(Me.hWnd, _
	"This is a test in API Message Box", _
	"API Message Box", vbInformation)
To use this technique in VB3, declare all parameters in the API call as integer. While calling, pass MB_ICONINFORMATION as the last parameter, instead of vbInformation. You can find the constant value for MB_ICONINFORMATION in the CONSTANT.txt file. Note that many of the intrinsic VB constants used with MsgBox also work with the MessageBox API. Now for the best news about this workaround-it's totally unnecessary under VB5! Timer (and other) events are never blocked by a MsgBox call when run from an EXE. It's important to understand that they'll still be blocked in the IDE, but take a look next time you compile and you'll see your clock just keeps on ticking.
Vasudevan Sampath
 
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