private async void ExecuteEditPlan(object o)
        {
            if (!(o is PlanViewModel))
            {
                return;
            }

            var editingPlan = o as PlanViewModel;

            //let's set up a little MVVM, cos that's what the cool kids are doing:
            var view = new AddPlanDialog
            {
                DataContext = new PlanViewModel()
                {
                    Id               = editingPlan.Id,
                    MachineId        = editingPlan.MachineId,
                    EmployeeId       = editingPlan.EmployeeId,
                    ProductId        = editingPlan.ProductId,
                    ExpectedQuantity = editingPlan.ExpectedQuantity,
                    ActualQuantity   = editingPlan.ActualQuantity,
                    StartTime        = editingPlan.StartTime,
                    EndTime          = editingPlan.EndTime,
                    IsProcessed      = editingPlan.IsProcessed,
                    //Employee = editingPlan.Employee,
                    //Machine = editingPlan.Machine,
                    //Product = editingPlan.Product
                }
            };

            //show the dialog
            var result = await DialogHost.Show(view, "RootDialog", OpenedPlanDialogEventHandler, ClosingPlanDialogEventHandler);

            //check the result...
            Console.WriteLine("Dialog was closed, the CommandParameter used to close it was: " + (result ?? "NULL"));
        }
        private async void ExecuteAddPlan(object o)
        {
            //let's set up a little MVVM, cos that's what the cool kids are doing:
            var view = new AddPlanDialog
            {
                DataContext = new PlanViewModel()
            };

            //show the dialog
            var result = await DialogHost.Show(view, "RootDialog", OpenedPlanDialogEventHandler, ClosingPlanDialogEventHandler);

            //check the result...
            Console.WriteLine("Dialog was closed, the CommandParameter used to close it was: " + (result ?? "NULL"));
        }