public void EndGetOperationById(IAsyncResult result)
        {
            OperationDto       operation   = OperationsService.EndGetOperationById(result);
            OperationViewModel operationVM = Operations.SingleOrDefault(o => o.Operation.Id == operation.Id);

            if (operationVM != null)
            {
                operationVM.Operation = operation;
            }
            else
            {
                Operations.Add(new OperationViewModel(operation));
            }
            InProgress = false;
        }