Detecting an Open Dialog Box

Thomas has a macro that performs various functions at timed intervals. Some of those functions should not be performed if a dialog box is open on the screen, because trying to perform them will cause an error in the functions. He wonders if there is some way, within the macro, to detect if a dialog box—any dialog box—is currently open. Thomas would rather detect the open dialog box rather than deal with a generated error.

Perhaps the only way to attempt to do this is to use FindWindow, which is actually part of the Windows API. Its purpose is to retrieve a handle to a particular open window. (A dialog box is nothing but an open window, and each dialog box has a name.) This approach won't tell you if any dialog box is open, but it will tell you if a specific dialog box is open.

Here is a quick example to show how the FindWindow function can be used:

Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
  (ByVal wClassName As Any, ByVal wWindowName As String) As Long

Sub testDialogOpen()
    Dim wHandle As Long
    Dim wName As String

    wName = "Find and Replace"
    wHandle = FindWindow(0&, wName)
    If wHandle = 0 Then
        MsgBox "Dialog window is not open"
    Else
        MsgBox "Dialog window is open"
    End If
End Sub

Note that the FindWindow function needs to be declared outside of your VBA procedure. Then, within the procedure, you need to specify the name of the dialog box you want to find out about. This is the name that appears in the title bar for the dialog box, and the FindWindow function is case insensitive. The return value for FindWindow will be a handle for the dialog box, if it is open. If it is not open, then the function returns a 0.

Remember, too, that dialog boxes can be of two types: modal and non-modal. If a particular dialog box is modal, then it must be dismissed before any other actions can be taken on the system. You'll want to do extensive testing with the dialog boxes at point, as you may get different performance from your macro depending on whether an open dialog box is modal or not.

WordTips is your source for cost-effective Microsoft Word training. (Microsoft Word is the most popular word processing software in the world.) This tip (12355) applies to Microsoft Word 97, 2000, 2002, and 2003. You can find a version of this tip for the ribbon interface of Word (Word 2007 and later) here: Detecting an Open Dialog Box.