UserViewVariantsController.cs

using System;
using System.Linq;
using DevExpress.ExpressApp;
using DevExpress.Persistent.Base;
using DevExpress.ExpressApp.Utils;
using DevExpress.ExpressApp.Model;
using DevExpress.ExpressApp.Actions;
using DevExpress.ExpressApp.Editors;
using DevExpress.ExpressApp.Templates;
using DevExpress.ExpressApp.Model.Core;
using DevExpress.ExpressApp.SystemModule;
using DevExpress.ExpressApp.ViewVariantsModule;

namespace UserViewVariants {
    public class UserViewVariantsController : ViewController {
        private const string STR_HasViewVariants_EnabledKey = "HasViewVariants";
        private const string STR_IsRootViewVariant_EnabledKey = "IsRootViewVariant";
        private const string STR_NewViewVariant_Id = "NewViewVariant";
        private const string STR_DeleteViewVariant_Id = "DeleteViewVariant";
        private const string STR_EditViewVariant_Id = "EditViewVariant";
        private const string STR_UserViewVariants_Image = "Action_Copy";
        private const string STR_NewViewVariant_Image = "Action_New";
        private const string STR_DeleteViewVariant_Image = "Action_Delete";
        private const string STR_EditViewVariant_Image = "Action_Edit";
        private const string STR_UserViewVariants_Id = "UserViewVariants";

        private readonly SingleChoiceAction userViewVariantsCore;
        protected ChangeVariantController changeVariantController;
        protected IModelList<IModelVariant> rootModelViewVariants;
        private IModelList<IModelView> modelViews;
        private IVariantsProvider variantsProvider;
        public UserViewVariantsController() {
            userViewVariantsCore = new SingleChoiceAction(this, STR_UserViewVariants_Id, PredefinedCategory.View) {
                ImageName = STR_UserViewVariants_Image,
                PaintStyle = ActionItemPaintStyle.CaptionAndImage,
                Caption = CaptionHelper.ConvertCompoundName(STR_UserViewVariants_Id),
                ItemType = SingleChoiceActionItemType.ItemIsOperation,
                ShowItemsOnClick = true
            };
            ChoiceActionItem addViewVariantItem = new ChoiceActionItem(STR_NewViewVariant_Id, CaptionHelper.ConvertCompoundName(STR_NewViewVariant_Id), STR_NewViewVariant_Id) {
                ImageName = STR_NewViewVariant_Image
            };
            ChoiceActionItem removeViewVariantItem = new ChoiceActionItem(STR_DeleteViewVariant_Id, CaptionHelper.ConvertCompoundName(STR_DeleteViewVariant_Id), STR_DeleteViewVariant_Id) {
                ImageName = STR_DeleteViewVariant_Image
            };
            ChoiceActionItem editViewVariantItem = new ChoiceActionItem(STR_EditViewVariant_Id, CaptionHelper.ConvertCompoundName(STR_EditViewVariant_Id), STR_EditViewVariant_Id) {
                ImageName = STR_EditViewVariant_Image
            };
            userViewVariantsCore.Items.Add(addViewVariantItem);
            userViewVariantsCore.Items.Add(editViewVariantItem);
            userViewVariantsCore.Items.Add(removeViewVariantItem);
            userViewVariantsCore.Execute += UserViewVariants_Execute;
        }
        private void UserViewVariants_Execute(object sender, SingleChoiceActionExecuteEventArgs e) {
            UserViewVariants(e);
        }
        protected virtual void UserViewVariants(SingleChoiceActionExecuteEventArgs e) {
            string data = Convert.ToString(e.SelectedChoiceActionItem.Data);
            if (data == STR_NewViewVariant_Id || data == STR_EditViewVariant_Id) {
                ShowViewVariantParameterDialog(e, data);
            }
            else if (data == STR_DeleteViewVariant_Id) {
                DeleteViewVariant();
            }
        }
        protected override void OnActivated() {
            base.OnActivated();
            Initialize();
            UpdateUserViewVariantsAction();
        }
        protected override void Dispose(bool disposing) { // It is important to release references here and not within the overridden OnDeactivated method, because this Controller is deactivated when changing the current View variant.
            if (disposing) {
                UnsubscribeFromEvents();
                changeVariantController = null;
                variantsProvider = null;
                rootModelViewVariants = null;
                modelViews = null;
            }
            base.Dispose(disposing);
        }
        private void UnsubscribeFromEvents() {
            userViewVariantsCore.Execute -= UserViewVariants_Execute;
            if ((changeVariantController != null) && (changeVariantController.ChangeVariantAction != null)) {
                changeVariantController.ChangeVariantAction.ExecuteCompleted -= ChangeVariantAction_ExecutedCompleted;
            }
        }
        private void Initialize() {
            changeVariantController = Frame.GetController<ChangeVariantController>();
            if(changeVariantController != null) {
                changeVariantController.ChangeVariantAction.Executed += ChangeVariantAction_ExecutedCompleted;
            }
            modelViews = (IModelList<IModelView>)View.Model.Application.Views;
            variantsProvider = Application.Modules.FindModule<ViewVariantsModule>().VariantsProvider;
            rootModelViewVariants = (IModelList<IModelVariant>)((IModelViewVariants)modelViews[GetRootViewId()]).Variants;
        }
        private void ChangeVariantAction_ExecutedCompleted(object sender, ActionBaseEventArgs e) {
            UpdateUserViewVariantsAction();
        }
        private string GetRootViewId() {
            VariantsInfo variantsInfo = GetVariantsInfo();
            return variantsInfo != null ? variantsInfo.RootViewId : View.Id;
        }
        protected virtual void ShowViewVariantParameterDialog(SingleChoiceActionExecuteEventArgs e, string mode) {
            string viewCaption = string.Empty;
            ViewVariantParameterObject parameter = new ViewVariantParameterObject(rootModelViewVariants);
            if (mode == STR_NewViewVariant_Id) {
                parameter.Caption = string.Format("{0}_{1:g}", View.Caption, DateTime.Now);
                viewCaption = CaptionHelper.GetLocalizedText("Texts", "NewViewVariantParameterCaption");
            }
            if (mode == STR_EditViewVariant_Id && (changeVariantController != null) && changeVariantController.ChangeVariantAction.SelectedItem != null) {
                parameter.Caption = changeVariantController.ChangeVariantAction.SelectedItem.Caption;
                viewCaption = CaptionHelper.GetLocalizedText("Texts", "EditViewVariantParameterCaption");
            }
            DialogController dialogController = Application.CreateController<DialogController>();
            dialogController.Accepting += dialogController_Accepting;
            dialogController.Tag = mode;
            var os = Application.CreateObjectSpace(typeof(ViewVariantParameterObject));
            DetailView dv = Application.CreateDetailView(os, parameter, false);
            dv.ViewEditMode = ViewEditMode.Edit;
            dv.Caption = viewCaption;
            e.ShowViewParameters.CreatedView = dv;
            e.ShowViewParameters.Controllers.Add(dialogController);
            e.ShowViewParameters.TargetWindow = TargetWindow.NewModalWindow;
        }
        protected void dialogController_Accepting(object sender, DialogControllerAcceptingEventArgs e) {
            DialogController dialogController = (DialogController)sender;
            dialogController.Accepting -= dialogController_Accepting;
            string data = Convert.ToString(dialogController.Tag);
            ViewVariantParameterObject parameter = dialogController.Window.View.CurrentObject as ViewVariantParameterObject;
            if (data == STR_NewViewVariant_Id) {
                NewViewVariant(parameter);
            }
            else if (data == STR_EditViewVariant_Id) {
                EditViewVariant(parameter);
            }
        }
        protected virtual void NewViewVariant(ViewVariantParameterObject parameter) {
            View.SaveModel(); //It is necessary to save the current View settings into the application model before copying them.
            string newViewVariantId = String.Format("{0}_{1}", GetRootViewId(), Guid.NewGuid()); //Identifier of a new view variant will be based on the identifier of the root view variant.
            IModelVariant newModelViewVariant = ((ModelNode)rootModelViewVariants).AddNode<IModelVariant>(newViewVariantId); // Adds a new child node of the IModelVariant type with a specific identifier to the parent IModelViewVariants node.
            newModelViewVariant.View = ((ModelNode)modelViews).AddClonedNode((ModelNode)View.Model, newViewVariantId) as IModelView; // Creates a new node of the IModelView type by cloning the settings of the current View and then sets the clone to the View property of the view variant created above. Beware of the specificity described at Q411979.
            newModelViewVariant.Caption = parameter.Caption; //Sets the Caption property of the view variant created above to the caption specified by an end-user in the dialog.
            if (rootModelViewVariants.Count == 1) { //It is necessary to add a default view variant node for the current View for correct operation of the Change Variant Action.
                IModelVariant currentModelViewVariant = ((ModelNode)rootModelViewVariants).AddNode<IModelVariant>(View.Id);
                currentModelViewVariant.Caption = CaptionHelper.GetLocalizedText("Texts", "DefaultViewVariantCaption");
                currentModelViewVariant.View = View.Model;
            }
            if(changeVariantController != null) {
                changeVariantController.CurrentFrameViewVariantsManager.RefreshVariants(); //Updates the Change Variant Action structure based on the model customizations above.
            }
            UpdateCurrentViewVariant(newViewVariantId); //Sets the current view variant to the newly created one.
            UpdateUserViewVariantsAction(); //Updates the items of our User View Variant Action based on the current the Change Variant Action structure. 
        }
        protected virtual void DeleteViewVariant() { //This method does almost the same work as NewViewVariant, but in reverse order.
            VariantsInfo variantsInfo = GetVariantsInfo(); //You should not be able to remove the root view variant.
            if (variantsInfo != null && variantsInfo.CurrentVariantId != GetRootViewId()) {
                UpdateCurrentViewVariant(string.Empty);
                rootModelViewVariants[variantsInfo.CurrentVariantId].Remove();
                modelViews[variantsInfo.CurrentVariantId].Remove();
                if(changeVariantController != null) {
                    changeVariantController.CurrentFrameViewVariantsManager.RefreshVariants();
                }
                UpdateUserViewVariantsAction();
            }
            if (rootModelViewVariants.Count == 1) {
                rootModelViewVariants.ClearNodes();
            }
        }
        protected virtual void EditViewVariant(ViewVariantParameterObject parameter) {
            VariantsInfo variantsInfo = GetVariantsInfo();
            if (variantsInfo != null) {
                rootModelViewVariants[variantsInfo.CurrentVariantId].Caption = parameter.Caption;
            }
            if(changeVariantController != null) {
                changeVariantController.CurrentFrameViewVariantsManager.RefreshVariants();
            }
        }
        protected virtual void UpdateCurrentViewVariant(string selectedViewId) {
            if(changeVariantController != null) {
                SingleChoiceAction action = changeVariantController.ChangeVariantAction;
                ChoiceActionItem selectedItem = action.Items.FindItemByID(selectedViewId);
                if(selectedItem != null) {
                    action.DoExecute(selectedItem);
                }
            }
        }
        private void UpdateUserViewVariantsAction() {
            bool hasViewVariants = (GetVariantsInfo() != null);
            UserViewVarintsAction.Items.FindItemByID(STR_DeleteViewVariant_Id).Enabled[STR_HasViewVariants_EnabledKey] =
                UserViewVarintsAction.Items.FindItemByID(STR_EditViewVariant_Id).Enabled[STR_HasViewVariants_EnabledKey]
                    = hasViewVariants;

            if ((changeVariantController != null) && changeVariantController.ChangeVariantAction.SelectedItem != null) {
                VariantInfo variantInfo = (VariantInfo)changeVariantController.ChangeVariantAction.SelectedItem.Data;
                UserViewVarintsAction.Items.FindItemByID(STR_DeleteViewVariant_Id).Enabled[STR_IsRootViewVariant_EnabledKey]
                    = variantInfo.ViewID != GetRootViewId();
            }
        }
        private VariantsInfo GetVariantsInfo() {
            return Application.Modules.FindModule<ViewVariantsModule>().FrameVariantsEngine.GetVariants(Frame.View);
        }
        public SingleChoiceAction UserViewVarintsAction {
            get { return userViewVariantsCore; }
        }
    }
}