角-Kendo treeview焦点()方法

Question

尝试在此柱塞中的treeview节点上使用focus()进行ElementRef。我在底线上评论了这两行，因为它们不起作用。

下面是代码清单的柱塞：

https://plnkr.co/edit/aUnechu6glXk5CMFsMex?p=preview

​

import { Component, ElementRef, ViewChild } from '@angular/core';


 @Component({
     selector: 'my-app',
     template: `
     <kendo-treeview
         #treeview
         [nodes]="data"
         textField="text"
         kendoTreeViewCheckable
         kendoTreeViewExpandable
         kendoTreeViewSelectable

         kendoTreeViewHierarchyBinding
         childrenField="items">
     </kendo-treeview>
 `
 })
 export export class AppComponent {
   @ViewChild("treeview") treeview: ElementRef;
     public data: any[] = [
         {
             text: "Furniture", items: [
                 { text: "Tables & Chairs" },
                 { text: "Sofas" },
                 { text: "Occasional Furniture" }
             ]
         },
         {
             text: "Decor", items: [
                 { text: "Bed Linen" },
                 { text: "Curtains & Blinds" },
                 { text: "Carpets" }
             ]
         }
     ]; 
     //let tree = this.treeview.nativeElement;
     //this.treeview.focus('0');
 }

​

根据它们的文档和示例，focus()方法如下：

https://www.telerik.com/kendo-angular-ui/components/treeview/api/TreeViewComponent/#toc-focus

如何在组件代码中以编程方式聚焦()，而不是放在文档中的click()事件？

Answer 1

代码需要在角的生命周期钩子内部或从方法中执行。我们需要一个ngAfterViewInit或自定义AppComponent.focus()方法，ViewChild有时间实例化TreeView实例：

ngAfterViewInit(){
   //XXX: this.treeview is the TreeViewComponent instance set by ViewChild decorator 
   this.treeview.focus('1');
}