State Persistence

TreeView state can be persisted by using enablePersistence. In which entire modal has been persisted excluding data source in order to maintain performance.

The model values of below are maintained through Id basis of tree node.

  • selected
  • checked
  • expanded/collapsed state

NOTE

“Ul-li” template option, state has been persisted by index.

TreeView stores its model in local storage / cookies of browser before page refreshes and reinitialized with their stored model after refresh.

  • html
  • <ej-treeview id="dragdrop" [fields]='field' [enablePersistence]='enablePersistence'></ej-treeview>
  • html
  • <script>
    
    import { Component, Inject } from '@angular/core';
    
    @Component({
        selector: 'control-content',
        templateUrl: 'app/components/treeview/enablePersistence.component.html'
    })
    export class enablePersistenceTreeViewComponent {
    
       public hierarchicalData: Object[] = [
            {
                id: 1, name: 'ASP.NET MVC Team', expanded: true,
                child: [
                    { id: 2, parentId: 1, name: 'Smith', isSelected: true },
                    { id: 3, parentId: 1, name: 'Johnson', isSelected: true },
                    { id: 4, parentId: 1, name: 'Anderson' },
                ]
            },
            {
                id: 5, name: 'Windows Team',
                child: [
                    { id: 6, parentId: 5, name: 'Clark' },
                    { id: 7, parentId: 5, name: 'Wright' },
                    { id: 8, parentId: 5, name: 'Lopez' },
                ]
            },
            {
                id: 9, name: 'Web Team',
                child: [
                    { id: 11, parentId: 9, name: 'Joshua' },
                    { id: 12, parentId: 9, name: 'Matthew' },
                    { id: 13, parentId: 9, name: 'David' },
                ]
            },
            {
                id: 14, name: 'Build Team',
                child: [
                    { id: 15, parentId: 14, name: 'Ryan' },
                    { id: 16, parentId: 14, name: 'Justin' },
                    { id: 17, parentId: 14, name: 'Robert' },
                ]
            },
            {
                id: 18, name: 'WPF Team',
                child: [
                    { id: 19, parentId: 18, name: 'Brown' },
                    { id: 20, parentId: 18, name: 'Johnson' },
                    { id: 21, parentId: 18, name: 'Miller' },
                ]
            }
        ];
        public field:Object ={ dataSource: this.hierarchicalData, id: 'id', text: 'name', child: 'child', selected: 'isSelected' };
        public enablePersistence:boolean = true;
    }
    
    <script>