DevGuru ADO Recordset::WillChangeRecord Event

EVENT: Recordset::WillChangeRecord

WillChangeRecord (adReason, cRecord, adStatus, pRecordset)

The WillChangeRecord event can be fired before the values for one or more Records in the Recordset have been changed.

The operations that can trigger this event would be either:

The first call to the AddNew, CancelBatch, CancelUpdate, Delete, Update, or the UpdateBatch methods,
The first and all subsequent calls to those same six methods.

If a filter has been used or is in place, you will only see the Records that are visible through the filter. Further, you cannot change the filter during this event.

In contrast, the RecordChangeComplete event can be fired after any changes in the values for one or more Record objects have been completed.

An event is simply a subroutine that can be called automatically after a specific operation has occurred. This subroutine can contain any code that you need to run when the event occurs. The subroutine will only be called if it is included in your code.

There are four parameters passed to this event.

The adReason parameter is one of seven of the EventReasonEnum constants that describe what pending operation caused this event to fire. Note that there is a total of fifteen of these constants, but only the following seven can actually be used by this parameter.

EventReasonEnum Constants

Constant	Value	Description
adRsnAddNew	1	A record is added
adRsnDelete	2	A record is deleted
adRsnFirstChange	11	Any operation that makes the first change to a record
adRsnUndoAddNew	5	An add is cancelled
adRsnUndoDelete	6	A delete is cancelled
adRsnUndoUpdate	4	An update is cancelled
adRsnUpdate	3	A record is updated

The cRecord parameter is a long value that is the number of the records that were changed.

The adStatus parameter is one of the EventStatusEnum constants that describes the current status of the event. If the action that triggered this event was successful, then the agrument will be set to adStatusOK. If the pending action cannot be cancelled, it will be set to adStatusCantDeny.

EventStatusEnum Constants

Constant	Value	Description
adStatusCancel	4	Cancels the operation that fired the event
adStatusCantDeny	3	Cannot cancel pending operation
adStatusErrorsOccurred	2	Indicates that warnings and/or errors occurred
adStatusOK	1	The operation that fired the event was successful
adStatusUnwantedEvent	5	The operation that generated the event cannot generate future events

The pRecordset parameter is the Recordset object to which this event applies.

Code (Visual Basic):
' Use the WithEvents keyword to designate that events
' can be handled by this Recordset object
Dim WithEvents objRecSet As ADODB.Recordset

' Note how the object name, objRecSet, is incorporated into the event Sub name
Private Sub objRecSet_WillChangeRecord(adReason As ADODB.EventReasonEnum, _
   cRecord As Long, _
   adStatus As ADODB.EventStatusEnum, _
   ByVal pRecordset As ADODB.Recordset )

' place any code you desire here, for example
Print cRecord & " records will be modified"

End Sub