Word Document Properties

Part III: Expanding Your VBA Horizons 
14_046500 ch08.qxp 12/5/06 5:36 PM Page 200

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‘ if there is no Help button. Raise an
error
‘ if any of these conditions is true.
Err.Raise vbObjectError + 2, _
“SpecialMsg.DefaultButton”, _
“The selected default button value is “ +
_
“incorrect. Choose a default button “ + _
“that matches the message box settings.”
Else
‘ Set the default button value.
UseDefault = vbDefaultButton3
End If
Case Button_4
If Not UseHelpButton Then
‘ Can’t have four buttons if there is no
‘ Help button, so raise an error.
Err.Raise vbObjectError + 2, _
“SpecialMsg.DefaultButton”, _
“The selected default button value is “ +
_
“incorrect. Choose a default button “ + _
“that matches the message box settings.”
Else
‘ Set the default button value.
UseDefault = vbDefaultButton4
End If
End Select
End Property
The logic that you use for error handling can become quite complex. There’s
no error handling for a 
DefaultButton
value of 
Button_1
because you 
can’t create a message box with no buttons (every message box has at least
one button). Only one setting results in a message box with just one button.
When you create a message box with 
vbOKOnly
and leave out the Help
button, there’s only one button on the message box. The 
Case Button_2
clause checks for this possibility and generates an error message when you
ask for the second button as a default on a message box with only one button.
The 
Case Button_3
error-handling logic is especially complex. When you
encounter a situation where the logic becomes this complex, it pays to take the
problem apart, solve the individual pieces, and then put the pieces together. A
message box has three buttons when you request the 
vbYesNoCancel
option.
The message box also has three buttons when you request the 
vbYesNo
option and a Help button. The message box never has three buttons when
using the 
vbOKOnly
option — even adding the Help button increases the
number of buttons to only two. The code uses all these criteria to look for 
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