0. Validation
1. Insert
2. Edit
3. Delete
4. Select

public abstract class PageStateMachine : Page
    {
      ...
        protected abstract ... Save();
        protected abstract ... Select();
        protected abstract ... Delete();
        protected abstract ... Validation();
      ...

    public enum PageState
    {
        Save = 0,
        Select = 2,
        Delete = 8,
        Cancel = 16
    }

public void Go(PageState pageState)
        {
            switch (pageState)
            {
                case PageState.Save:
                    {
                        var error = Validation();
                        Message = error.HasError ? error.Message : Save().Message;
                        if (!error.HasError)
                        {
                            ClearControls();
                            RefreshList();
                        }

                        break;
                    }
                case PageState.Select:
                    {
                        Message = Select().Message;
                        break;
                    }
                    break;
                case PageState.Delete:
                    {
                        Message = Delete().Message;
                        ClearControls();
                        RefreshList();
                        break;
                    }
                case PageState.Cancel:
                    {
                        Message = string.Empty;
                        ClearControls();
                        break;
                    }
            }
        }