There are several possible errors that can occur within your Visual Basic program if you attempt to edit a record that is on a data page that is already locked. The most common errors you'll encounter are Error 3260 and Error 3197. Error 3260 occurs whenever you attempt to edit a record that is stored on a page that is already locked by another user or program. You can handle this error by attempting a read at another time. Error 3197 occurs when your program attempts to read a record that has been updated or deleted since you last refreshed the data set. You can handle this error by reloading the record into the data set (usually by invoking the Edit method again). Refer to Listing 14.38 as an example.

Listing 14.38. Handling page lock errors during edits. Public Sub PageLockErrors(LockErr As Integer) ' ' handle errors due to page locks ' Static nTries As Integer Dim nMaxTries As Integer Dim nLoop As Integer Dim nTemp As Integer ' nMaxTries = 3 ' Select Case LockErr Case 3197 ' data changed rsObject.Edit ' re-read changed record Case 3260, 3816 ' currently locked nTries = nTries + 1 ' try again If nTries > nMaxTries Then ' too manytimes? nTemp = MsgBox(Error, vbRetryCancel, "Error " + Str(Err)) If nTemp = vbRetry Then ' user said try again nTries = 1 ' start all over End If End If End Select ' DBEngine.Idle ' free up old locks DoEvents ' let messages catch up ' For nLoop = 1 To 2000 ' 2000 millisecond pause ' empty loop Next nLoop Resume ' End Sub

Notice the use of the Idle and DoEvents methods in the error handler in Listing 14.38. These two lines allow Visual Basic and Windows to pass any backlogged messages to each other that may relate to old page locks that are no longer active.