Drag & Drop for Hierarchical Data Structure

import { NgModule, Component, enableProdMode, ViewChild } from '@angular/core'; import { BrowserModule } from '@angular/platform-browser'; import { platformBrowserDynamic } from '@angular/platform-browser-dynamic'; import { DxTreeViewModule, DxTreeViewComponent, DxSortableModule } from 'devextreme-angular'; import { Service, FileSystemItem } from './app.service'; if(!/localhost/.test(document.location.host)) { enableProdMode(); } @Component({ selector: 'demo-app', templateUrl: 'app/app.component.html', styleUrls: ['app/app.component.css'], providers: [Service] }) export class AppComponent { @ViewChild('treeviewDriveC') treeviewDriveC: DxTreeViewComponent; @ViewChild('treeviewDriveD') treeviewDriveD: DxTreeViewComponent; itemsDriveC: FileSystemItem[]; itemsDriveD: FileSystemItem[]; constructor(service: Service) { this.itemsDriveC = service.getItemsDriveC(); this.itemsDriveD = service.getItemsDriveD(); } onDragChange(e) { if(e.fromComponent === e.toComponent) { const fromNode = this.findNode(this.getTreeView(e.fromData), e.fromIndex); const toNode = this.findNode(this.getTreeView(e.toData), this.calculateToIndex(e)); if (toNode !== null && this.isChildNode(fromNode, toNode)) { e.cancel = true; } } } onDragEnd(e) { if(e.fromComponent === e.toComponent && e.fromIndex === e.toIndex) { return; } const fromTreeView = this.getTreeView(e.fromData); const toTreeView = this.getTreeView(e.toData); const fromNode = this.findNode(fromTreeView, e.fromIndex); const toNode = this.findNode(toTreeView, this.calculateToIndex(e)); if(e.dropInsideItem && toNode !== null && !toNode.itemData.isDirectory) { return; } const fromTopVisibleNode = this.getTopVisibleNode(e.fromComponent); const toTopVisibleNode = this.getTopVisibleNode(e.toComponent); const fromItems = fromTreeView.option('items'); const toItems = toTreeView.option('items'); this.moveNode(fromNode, toNode, fromItems, toItems, e.dropInsideItem); fromTreeView.option('items', fromItems); toTreeView.option('items', toItems); fromTreeView.scrollToItem(fromTopVisibleNode); toTreeView.scrollToItem(toTopVisibleNode); } getTreeView(driveName) { return driveName === 'driveC' ? this.treeviewDriveC.instance : this.treeviewDriveD.instance; } calculateToIndex(e) { if(e.fromComponent != e.toComponent || e.dropInsideItem) { return e.toIndex; } return e.fromIndex >= e.toIndex ? e.toIndex : e.toIndex + 1; } findNode(treeView, index) { const nodeElement = treeView.element().querySelectorAll('.dx-treeview-node')[index]; if(nodeElement) { return this.findNodeById(treeView.getNodes(), nodeElement.getAttribute('data-item-id')); } return null; } findNodeById(nodes, id) { for(var i = 0; i < nodes.length; i++) { if(nodes[i].itemData.id == id) { return nodes[i]; } if(nodes[i].children) { const node = this.findNodeById(nodes[i].children, id); if(node != null) { return node; } } } return null; } moveNode(fromNode, toNode, fromItems, toItems, isDropInsideItem) { const fromNodeContainingArray = this.getNodeContainingArray(fromNode, fromItems); const fromIndex = fromNodeContainingArray.findIndex(item => item.id == fromNode.itemData.id); fromNodeContainingArray.splice(fromIndex, 1); if(isDropInsideItem) { toNode.itemData.items.splice(toNode.itemData.items.length, 0, fromNode.itemData); } else { const toNodeContainingArray = this.getNodeContainingArray(toNode, toItems); const toIndex = toNode === null ? toNodeContainingArray.length : toNodeContainingArray.findIndex(item => item.id == toNode.itemData.id); toNodeContainingArray.splice(toIndex, 0, fromNode.itemData); } } getNodeContainingArray(node, rootArray) { return node === null || node.parent === null ? rootArray : node.parent.itemData.items; } isChildNode(parentNode, childNode) { let parent = childNode.parent; while(parent !== null) { if(parent.itemData.id === parentNode.itemData.id) { return true; } parent = parent.parent; } return false; } getTopVisibleNode(component) { const treeViewElement = component.element(); const treeViewTopPosition = treeViewElement.getBoundingClientRect().top; const nodes = treeViewElement.querySelectorAll(".dx-treeview-node"); for(let i = 0; i < nodes.length; i++) { const nodeTopPosition = nodes[i].getBoundingClientRect().top; if(nodeTopPosition >= treeViewTopPosition) { return nodes[i]; } } return null; } } @NgModule({ imports: [ BrowserModule, DxTreeViewModule, DxSortableModule ], declarations: [AppComponent], bootstrap: [AppComponent] }) export class AppModule { } platformBrowserDynamic().bootstrapModule(AppModule);

::ng-deep .form { display: flex; } ::ng-deep .form>div { display: inline-block; vertical-align: top; } ::ng-deep #treeviewDriveC, ::ng-deep #treeviewDriveD { margin-top: 10px; } ::ng-deep .drive-header { min-height: auto; padding: 0px; cursor: default; } ::ng-deep .drive-panel { padding: 20px 30px; font-size: 115%; font-weight: bold; border-right: 1px solid rgba(165, 165, 165, 0.4); height: 100%; } ::ng-deep .drive-panel:last-of-type { border-right: none; }

import { Injectable } from '@angular/core'; export class FileSystemItem { id: string; name: string; icon: string; isDirectory: boolean; items?: FileSystemItem[]; expanded?: boolean; } const itemsDriveD: FileSystemItem[] = []; const itemsDriveC: FileSystemItem[] = [{ id: '1', name: "Documents", icon: 'activefolder', isDirectory: true, expanded: true, items: [ { id: '2', name: "Projects", icon: 'activefolder', isDirectory: true, expanded: true, items: [ { id: '3', name: "About.rtf", icon: 'file', isDirectory: false }, { id: '4', name: "Passwords.rtf", icon: 'file', isDirectory: false } ] }, { id: '5', name: "About.xml", icon: 'file', isDirectory: false }, { id: '6', name: "Managers.rtf", icon: 'file', isDirectory: false }, { id: '7', name: "ToDo.txt", icon: 'file', isDirectory: false }], }, { id: '8', name: "Images", icon: 'activefolder', isDirectory: true, expanded: true, items: [ { id: '9', name: "logo.png", icon: 'file', isDirectory: false }, { id: '10', name: "banner.gif", icon: 'file', isDirectory: false }] }, { id: '11', name: "System", icon: 'activefolder', isDirectory: true, expanded: true, items: [ { id: '12', name: "Employees.txt", icon: 'file', isDirectory: false }, { id: '13', name: "PasswordList.txt", icon: 'file', isDirectory: false } ] }, { id: '14', name: "Description.rtf", icon: 'file', isDirectory: false }, { id: '15', name: "Description.txt", icon: 'file', isDirectory: false } ]; @Injectable() export class Service { getItemsDriveC(): FileSystemItem[] { return itemsDriveC; } getItemsDriveD(): FileSystemItem[] { return itemsDriveD; } }

// In real applications, you should not transpile code in the browser. You can see how to create your own application with Angular and DevExtreme here: // https://js.devexpress.com/Documentation/Guide/Angular_Components/Getting_Started/Create_a_DevExtreme_Application/ System.config({ transpiler: 'ts', typescriptOptions: { module: "system", emitDecoratorMetadata: true, experimentalDecorators: true }, meta: { 'typescript': { "exports": "ts" }, 'devextreme/localization.js': { "esModule": true } }, paths: { 'npm:': 'https://unpkg.com/' }, map: { 'ts': 'npm:plugin-typescript@8.0.0/lib/plugin.js', 'typescript': 'npm:typescript@3.5.3/lib/typescript.js', '@angular': 'npm:@angular', 'tslib': 'npm:tslib@2.1.0/tslib.js', 'rxjs': 'npm:rxjs@6.4.0', 'rrule': 'npm:rrule@2.6.6/dist/es5/rrule.js', 'luxon': 'npm:luxon@1.25.0/build/global/luxon.min.js', 'es6-object-assign': 'npm:es6-object-assign@1.1.0', 'devextreme': 'npm:devextreme@20.2.5', 'jszip': 'npm:jszip@3.5.0/dist/jszip.min.js', 'devextreme-quill': 'npm:devextreme-quill@0.9.8/dist/dx-quill.min.js', 'devexpress-diagram': 'npm:devexpress-diagram@2.0.11', 'devexpress-gantt': 'npm:devexpress-gantt@2.0.18', 'devextreme-angular': 'npm:devextreme-angular@20.2.5', 'preact': 'npm:preact@10.5.11/dist/preact.js', 'preact/hooks': 'npm:preact@10.5.11/hooks/dist/hooks.js' }, packages: { 'app': { main: './app.component.ts', defaultExtension: 'ts' }, 'devextreme': { defaultExtension: 'js' }, 'devextreme/events/utils': { main: 'index' }, 'devextreme/events': { main: 'index' }, 'es6-object-assign': { main: './index.js', defaultExtension: 'js' } }, packageConfigPaths: [ "npm:@angular/*/package.json", "npm:@angular/common/*/package.json", "npm:rxjs/package.json", "npm:rxjs/operators/package.json", "npm:devextreme-angular/*/package.json", "npm:devextreme-angular/ui/*/package.json", "npm:devextreme-angular/package.json", "npm:devexpress-diagram/package.json", "npm:devexpress-gantt/package.json", ] });

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