I really hope someone has an answer to this.

I'm writing an auto-faxing program which scans our registration
database every minute and uses Word to perform merges which print to a
third party fax program.

Co-workers of mine will create merge templates whose merge fields will
inevitably be old or just incorrect (as they have been with email
templates in the past) and cause the Check dialog box to display to
prompt a user to remove bad merge fields.

Having a dialog box display when you're trying to automate presents a
problem as the code halts. I can't have this. One work around that
I've tried is to parse the 'code' property of the mailmerge field and
compare a substring of it to the data fields. If there isn't a match
then I throw an error. However, this method is not full proof (user
edits in the merge fields could break the parsing) and I would rather
have Word just throw an error if the merge fields are incorrect.

I just need to report the error to a log and not have the dialog box
display.

My code in VB.NET follows:

Public Function OpenMailMerge(ByVal DataFileName As String, ByVal
strTemplatePathName As String, ByRef MergedDoc As Word.Document, ByVal
PrintToFaxFacts As Boolean) As Boolean
     
       Dim doc As Word.Document
       Dim i, j As Integer
       Dim mMergeDataSource As Word.MailMergeDataSource
       Dim wb As Object

       Try
           If IO.File.Exists(strTemplatePathName) = False Then
               Throw New Exception("MS Word Template path does not
exist!")
           End If
           If strTemplatePathName.EndsWith("dot") = False Then
               Throw New Exception("Template file is not a valid MS
Word Template!")
           End If

           'NOTE: comma delimited file already generated
           If IO.File.Exists(DataFileName) = False Then
               Throw New Exception("Data file path does not exist!")
           End If

           doc = wrd.Documents.Add(strTemplatePathName)
           mMergeDataSource = doc.MailMerge.DataSource
           doc.MailMerge.OpenDataSource(DataFileName, , False, True,
True, False)

           'visible only for diagnosing purposes
           wrd.Visible = True

           doc.MailMerge.SuppressBlankLines = True
           wrd.Options.PrintBackground = False
           doc.MailMerge.Destination =
Word.WdMailMergeDestination.wdSendToNewDocument

           If PrintToFaxFacts = True Then
               wb = wrd.WordBasic
               wb.FilePrintSetup(Printer:="Copia FFMERGE Driver",
DoNotSetAsSysDefault:=1)
           End If

           'Parse through mailmerge fields and compare to data fields
           Dim DataFieldExists As Boolean = False
           For i = 1 To doc.MailMerge.Fields.Count
               For j = 1 To doc.MailMerge.DataSource.DataFields.Count
                   If
LCase(doc.MailMerge.Fields.Item(i).Code.Text).IndexOf(" " &
LCase(doc.MailMerge.DataSource.DataFields.Item(j).Name) & " ") > -1
Then
                       DataFieldExists = True
                       Exit For
                   End If
               Next

               If DataFieldExists = False Then
                   Throw New Exception("Data field on MS Word
template not found!!!")
               End If
               DataFieldExists = False
           Next

           'Try-Catch block doesn't really help as the dialog box
displays
           Try
               doc.MailMerge.Execute()
           Catch ex As Exception
               Throw ex
           End Try

           MergedDoc = wrd.ActiveDocument

       Catch exc As Exception
           Throw exc
       End Try
   End Function