///--------------------------------------------------------------------------------
        /// <summary>This method updates the view model data and sends update command back
        /// to the solution builder.</summary>
        ///--------------------------------------------------------------------------------
        protected override void OnUpdate()
        {
            // send update for any updated children
            foreach (StateModelViewModel item in StateModels)
            {
                if (item.IsEdited == true)
                {
                    item.Update();
                }
            }
            // send update for any new children
            foreach (StateModelViewModel item in ItemsToAdd.OfType <StateModelViewModel>())
            {
                item.Update();
                StateModels.Add(item);
            }
            ItemsToAdd.Clear();

            // send delete for any deleted children
            foreach (StateModelViewModel item in ItemsToDelete.OfType <StateModelViewModel>())
            {
                item.Delete();
                StateModels.Remove(item);
            }
            ItemsToDelete.Clear();

            // reset modified for children
            foreach (StateModelViewModel item in StateModels)
            {
                item.ResetModified(false);
            }
        }
        ///--------------------------------------------------------------------------------
        /// <summary>This method applies statemodel deletes.</summary>
        ///--------------------------------------------------------------------------------
        public void ProcessDeleteStateModelPerformed(StateModelEventArgs data)
        {
            try
            {
                bool isItemMatch = false;
                if (data != null && data.StateModel != null)
                {
                    foreach (StateModelViewModel item in StateModels.ToList <StateModelViewModel>())
                    {
                        if (item.StateModel.StateModelID == data.StateModel.StateModelID)
                        {
                            // remove item from tabs, if present
                            WorkspaceEventArgs message = new WorkspaceEventArgs();
                            message.ItemID = item.StateModel.StateModelID;
                            Mediator.NotifyColleagues <WorkspaceEventArgs>(MediatorMessages.Command_CloseItemRequested, message);

                            // delete children
                            for (int i = item.Items.Count - 1; i >= 0; i--)
                            {
                                if (item.Items[i] is StateViewModel)
                                {
                                    StateViewModel child        = item.Items[i] as StateViewModel;
                                    StateEventArgs childMessage = new StateEventArgs();
                                    childMessage.State        = child.State;
                                    childMessage.StateModelID = item.StateModel.StateModelID;
                                    childMessage.Solution     = Solution;
                                    childMessage.WorkspaceID  = child.WorkspaceID;
                                    item.ProcessDeleteStatePerformed(childMessage);
                                }
                            }

                            // delete item
                            isItemMatch = true;
                            StateModels.Remove(item);
                            Entity.StateModelList.Remove(item.StateModel);
                            Items.Remove(item);
                            Entity.ResetModified(true);
                            OnUpdated(this, null);
                            break;
                        }
                    }
                    if (isItemMatch == false)
                    {
                        ShowIssue(DisplayValues.Issue_DeleteItemNotFound);
                    }
                }
            }
            catch (Exception ex)
            {
                ShowIssue(ex.Message + ex.StackTrace);
            }
        }
 ///--------------------------------------------------------------------------------
 /// <summary>This method deletes an instance of StateModel from the view model.</summary>
 ///
 /// <param name="itemView">The StateModel to delete.</param>
 ///--------------------------------------------------------------------------------
 public void DeleteStateModel(StateModelViewModel itemView)
 {
     itemView.Updated -= Children_Updated;
     StateModels.Remove(itemView);
     Delete(itemView);
 }