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RollBack Method

Transaction Roll Back Method

Rolls back all changes made to the model during the transaction.

Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 25.0.0.0 (25.0.0.0)
Syntax 
public TransactionStatus RollBack()

Return Value

TransactionStatus
If finished successfully, this method returns TransactionStatus.RolledBack.

Be aware that the returned status does not have to be necessarily the same like the status returned by GetStatus even when the method is called immediately after rolling back the transaction. Such difference may happen due to actions made by a transaction finalizer, if there was one set. (See FailureHandlingOptions for more details.)

Exceptions
Exception Condition
InvalidOperationException The current status of the transaction is not 'Started'. Transaction must be started before calling Commit or Rollback. -or- The transaction's document is currently in failure mode. No transaction operations are permitted until failure handling is finished.
Remarks
By rolling back a transaction, all changes made to the model are discarded. RollBack may only be called for a transaction that has been started. (Use the GetStatus method to check the current state.) Be aware that rolling back may be delayed (as a result of failure handling.) Callers should always check the returned status to test whether a transaction was rolled back successfully. Only after rolling back is fully completed, the transaction may be started again.
Example 
public bool CreateGrid(Autodesk.Revit.DB.Document document, XYZ p1, XYZ p2)
{
   // All and any transaction should be enclosed in a 'using'
   // block or guarded within a try-catch-finally blocks
   // to guarantee that a transaction does not out-live its scope.
   using (Transaction transaction = new Transaction(document, "Creating Grid"))
   {
      // Must start a transaction to be able to modify a document
      if (TransactionStatus.Started == transaction.Start())
      {
         // We create a line and use it as an argument to create a grid
         Line gridLine = Line.CreateBound(p1, p2);

         if ((null != gridLine) && (null != Grid.Create(document, gridLine)))
         {
             if (TransactionStatus.Committed == transaction.Commit())
             {
                return true;
             }
         }

         // For we were unable to create the grid, we will roll the transaction back
         // (although on this simplified case we know there weren't any other changes)

         transaction.RollBack();
      }
   }
   return false;
}
See Also