极客教程Angular PrimeNG TreeTable Lazy
Angular PrimeNG是一个开源框架，拥有丰富的原生Angular UI组件，可用于出色的造型，这个框架可用于制作响应式网站，非常容易。在这篇文章中，我们将看到如何在Angular PrimeNG中使用TreeTable Lazy Loading。
Angular PrimeNG TreeTable Lazy是用来懒惰地加载TreeTable组件的数据。它在需要的时候加载数据，使TreeTable更具互动性和用户友好性。它有助于处理大型数据集，即每次分页或排序时，通过调用相应的回调来加载少量的数据，而不是加载整个数据。
语法:
// In app.component.html
<p-treeTable
[columns]="cols"
[value]="tableData"
[lazy]="true"
(onLazyLoad)="loadNodes($event)"
[loading]="loading">
...
</p-treeTable>
// In app.component.ts
loadNodes(event) {
// lazy function
}
创建Angular应用程序和模块安装。
第1步：使用以下命令创建一个Angular应用程序。
ng new appname
第2步：创建你的项目文件夹即appname后，使用以下命令移动到它。
cd appname
第3步：在你给定的目录中安装PrimeNG。
npm install primeng --save
npm install primeicons --save
项目结构：它将看起来像如下。
例子1：下面是一个简单的例子，演示Angular PrimeNG TreeTable Lazy的使用。
<h2 style="color: green">GeeksforGeeks</h2>
<h4>Angular PrimeNG TreeTable Lazy</h4>
<p-treeTable [columns]="cols"
[value]="tableData"
[lazy]="true"
(onLazyLoad)="loadNodes($event)"
[loading]="loading">
<ng-template pTemplate="header">
<tr>
<th>First Name</th>
<th>Last Name</th>
<th>Age</th>
</tr>
</ng-template>
<ng-template pTemplate="body"
let-rowNode let-rowData="rowData">
<tr>
<td>
<p-treeTableToggler [rowNode]="rowNode">
</p-treeTableToggler>
{{ rowData.firstname }}
</td>
<td>{{ rowData.lastname }}</td>
<td>{{ rowData.age }}</td>
</tr>
</ng-template>
</p-treeTable>
import { Component, OnInit } from "@angular/core";
import { NodeService } from "./nodeservice";
import { TreeNode } from "primeng/api";
@Component({
selector: "app-root",
templateUrl: "./app.component.html",
})
export class AppComponent {
tableData: TreeNode[] = [];
cols: any[] = [];
loading: boolean = false;
constructor(private nodeService: NodeService) {}
ngOnInit() {
this.cols = [
{ field: "firstname", header: "First Name" },
{ field: "lastname", header: "Last Name" },
{ field: "age", header: "Age" },
];
this.loading = true;
}
loadNodes(event: any) {
this.loading = true;
setTimeout(() => {
this.tableData = [
{
data: {
firstname: "David",
lastname: "ace",
age: "40",
},
children: [
{
data: {
firstname: "Nathan",
lastname: "ace",
age: "16",
},
children: [
{
data: {
firstname: "Abe",
lastname: "ace",
age: "12",
},
},
{
data: {
firstname: "Ksi",
lastname: "ace",
age: "12",
},
},
],
},
{
data: {
firstname: "Shane",
lastname: "ace",
age: "14",
},
},
],
},
{
data: {
firstname: "Warner",
lastname: "ace",
age: "55",
},
children: [
{
data: {
lastname: "ace",
firstname: "Michelle",
age: "20",
},
},
{
data: {
firstname: "Charlie",
lastname: "ace",
age: "24",
},
},
],
},
{
data: {
firstname: "Max",
lastname: "ace",
age: "55",
},
children: [
{
data: {
firstname: "Michelle",
lastname: "ace",
age: "20",
},
},
{
data: {
firstname: "Charlie",
lastname: "ace",
age: "24",
},
},
],
},
{
data: {
firstname: "Willy",
lastname: "ace",
age: "55",
},
children: [
{
data: {
firstname: "Michelle",
lastname: "ace",
age: "20",
},
},
{
data: {
firstname: "Charlie",
lastname: "ace",
age: "24",
},
},
],
},
{
data: {
firstname: "Miley",
lastname: "ace",
age: "55",
},
children: [
{
data: {
firstname: "Michelle",
lastname: "ace",
age: "20",
},
},
{
data: {
firstname: "Charlie",
lastname: "ace",
age: "24",
},
},
],
},
{
data: {
firstname: "Sam",
lastname: "ace",
age: "55",
},
children: [
{
data: {
firstname: "Michelle",
lastname: "ace",
age: "20",
},
},
{
data: {
firstname: "Charlie",
lastname: "ace",
age: "24",
},
},
],
},
{
data: {
firstname: "James",
lastname: "ace",
age: "55",
},
children: [
{
data: {
firstname: "Michelle",
lastname: "ace",
age: "20",
},
},
{
data: {
lastname: "ace",
firstname: "Charlie",
age: "24",
},
},
],
},
];
this.loading = false;
}, 1000);
}
}
import { NgModule } from "@angular/core";
import { BrowserModule } from "@angular/platform-browser";
import { FormsModule } from "@angular/forms";
import { HttpClientModule } from "@angular/common/http";
import { BrowserAnimationsModule }
from "@angular/platform-browser/animations";
import { AppComponent } from "./app.component";
import { NodeService } from "./nodeservice";
import { TreeTableModule } from "primeng/treetable";
@NgModule({
imports: [
BrowserModule,
BrowserAnimationsModule,
TreeTableModule,
HttpClientModule,
FormsModule,
],
declarations: [AppComponent],
bootstrap: [AppComponent],
providers: [NodeService],
})
export class AppModule {}
输出:
例子2：下面是另一个例子，演示Angular PrimeNG TreeTable Lazy的使用，我们在这里偷懒加载数据5秒。
<h2 style="color: green">GeeksforGeeks</h2>
<h4>Angular PrimeNG TreeTable Lazy</h4>
<p-treeTable [columns]="cols"
[value]="tableData"
[lazy]="true"
(onLazyLoad)="loadNodes($event)"
[loading]="loading">
<ng-template pTemplate="header">
<tr>
<th>First Name</th>
<th>Last Name</th>
<th>Age</th>
</tr>
</ng-template>
<ng-template pTemplate="body"
let-rowNode let-rowData="rowData">
<tr>
<td>
<p-treeTableToggler [rowNode]="rowNode">
</p-treeTableToggler>
{{ rowData.firstname }}
</td>
<td>{{ rowData.lastname }}</td>
<td>{{ rowData.age }}</td>
</tr>
</ng-template>
</p-treeTable>
import { Component, OnInit } from "@angular/core";
import { NodeService } from "./nodeservice";
import { TreeNode } from "primeng/api";
@Component({
selector: "app-root",
templateUrl: "./app.component.html",
})
export class AppComponent {
tableData: TreeNode[] = [];
cols: any[] = [];
loading: boolean = false;
constructor(private nodeService: NodeService) {}
ngOnInit() {
this.cols = [
{ field: "firstname", header: "First Name" },
{ field: "lastname", header: "Last Name" },
{ field: "age", header: "Age" },
];
this.loading = true;
}
loadNodes(event: any) {
this.loading = true;
setTimeout(() => {
this.tableData = [
{
data: {
firstname: "David",
lastname: "ace",
age: "40",
},
children: [
{
data: {
firstname: "Nathan",
lastname: "ace",
age: "16",
},
children: [
{
data: {
firstname: "Abe",
lastname: "ace",
age: "12",
},
},
{
data: {
firstname: "Ksi",
lastname: "ace",
age: "12",
},
},
],
},
{
data: {
firstname: "Shane",
lastname: "ace",
age: "14",
},
},
],
},
{
data: {
firstname: "Warner",
lastname: "ace",
age: "55",
},
children: [
{
data: {
lastname: "ace",
firstname: "Michelle",
age: "20",
},
},
{
data: {
firstname: "Charlie",
lastname: "ace",
age: "24",
},
},
],
},
{
data: {
firstname: "Max",
lastname: "ace",
age: "55",
},
children: [
{
data: {
firstname: "Michelle",
lastname: "ace",
age: "20",
},
},
{
data: {
firstname: "Charlie",
lastname: "ace",
age: "24",
},
},
],
},
{
data: {
firstname: "Willy",
lastname: "ace",
age: "55",
},
children: [
{
data: {
firstname: "Michelle",
lastname: "ace",
age: "20",
},
},
{
data: {
firstname: "Charlie",
lastname: "ace",
age: "24",
},
},
],
},
{
data: {
firstname: "Miley",
lastname: "ace",
age: "55",
},
children: [
{
data: {
firstname: "Michelle",
lastname: "ace",
age: "20",
},
},
{
data: {
firstname: "Charlie",
lastname: "ace",
age: "24",
},
},
],
},
{
data: {
firstname: "Sam",
lastname: "ace",
age: "55",
},
children: [
{
data: {
firstname: "Michelle",
lastname: "ace",
age: "20",
},
},
{
data: {
firstname: "Charlie",
lastname: "ace",
age: "24",
},
},
],
},
{
data: {
firstname: "James",
lastname: "ace",
age: "55",
},
children: [
{
data: {
firstname: "Michelle",
lastname: "ace",
age: "20",
},
},
{
data: {
lastname: "ace",
firstname: "Charlie",
age: "24",
},
},
],
},
];
this.loading = false;
}, 5000);
}
}
import { NgModule } from "@angular/core";
import { BrowserModule } from "@angular/platform-browser";
import { FormsModule } from "@angular/forms";
import { HttpClientModule } from "@angular/common/http";
import { BrowserAnimationsModule }
from "@angular/platform-browser/animations";
import { AppComponent } from "./app.component";
import { NodeService } from "./nodeservice";
import { TreeTableModule } from "primeng/treetable";
@NgModule({
imports: [
BrowserModule,
BrowserAnimationsModule,
TreeTableModule,
HttpClientModule,
FormsModule,
],
declarations: [AppComponent],
bootstrap: [AppComponent],
providers: [NodeService],
})
export class AppModule {}
输出:
