Angular PrimeNG Form TreeSelect Single Component

Angular PrimeNG is an open-source library that consists of native Angular UI components that are used for great styling and this framework is used to make responsive websites with very much ease. In this article, we will be seeing the Angular PrimeNG Form TreeSelect Single Component.

The TreeSelect Component allows the users to select items from hierarchical data. It accepts an array of TreeNodes as its options property to show the data. In the TreeSelect single selection mode, one item from the hierarchy can be selected.

Angular PrimeNG Form TreeSelect Single Properties:

• options: This property accepts an array of TreeNodes as its value to display the TreeSelect component.
• selectionMode: This property is used to set the selection mode of the TreeSelect Component. The accepted values are “single”, “multiple”, and “checkbox”. The default value is “single”.
• display: This property defines how the selected item(s) will be displayed. The accepted values are “comma” and “chip”. The default value is “chip”.
• placeholder: The placeholder property is used to set the placeholder to display when no items are selected.

Syntax:

<p-treeSelect 
    [(ngModel)]="..."
    selectionMode="single" 
    display="..."
    [options]="..." 
    placeholder="...>
</p-treeSelect>

Creating Angular Application and Installing the Module:

Step 1: Create an Angular application using the following command.

ng new appname

Step 2: After creating your project folder i.e. appname, move to it using the following command.

cd appname

Step 3: Finally, Install PrimeNG in your given directory.

npm install primeng --save
npm install primeicons --save

Project Structure: The project Structure will look like this after following the above steps:

Project Structure

Example 1: This example illustrates the use of the single selection mode of the TreeSelect component. Here only one node can be selected at a time, it can be a parent node or a child.

• app.component.html:

HTML

<h2 style="color: green">GeeksforGeeks</h2>
<h3>
    Angular PrimeNG Form
    TreeSelect Single Component
</h3>

<p-treeSelect
    [(ngModel)]="selected"
    selectionMode="single"
    [options]="nodes"
    placeholder="Select a Node">
</p-treeSelect>

• app.component.ts:

Javascript

import { Component } from "@angular/core";
import { TreeNode } from "primeng/api";

@Component({
    selector: "app-root",
    templateUrl: "./app.component.html",
})

export class AppComponent {
    nodes: TreeNode[] = [];
    selected: any;
    ngOnInit()
    {
        this.nodes = [
            {
                "label": "Work",
                "icon": "pi pi-folder",
                "children": [
                    {
                        "label": "data.json",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "sales.docx",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "presentation.pptx",
                        "icon": "pi pi-file"
                    }
                ]
            },
            {
                "label": "Home",
                "icon": "pi pi-folder",
                "children": [
                    {
                        "label": "grocery.word",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "picture.jpeg",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "homeplan.png",
                        "icon": "pi pi-file"
                    }
                ]
            },
            {
                "label": "Multimedia",
                "icon": "pi pi-folder",
                "children": [
                    {
                        "label": "infinity-war.mp4",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "you.mp3",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "endgame.mp4",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "MI.mp4",
                        "icon": "pi pi-file"
                    }
                ]
            }
        ];
    }
}

• app.module.ts:

Javascript

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { BrowserAnimationsModule }
    from '@angular/platform-browser/animations';
import { AppComponent } from './app.component';
import { FormsModule } from '@angular/forms';
import { TreeSelectModule } from 'primeng/treeselect';

@NgModule({
    imports: [
        BrowserModule,
        BrowserAnimationsModule,
        TreeSelectModule,
        FormsModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent],
})
export class AppModule { }

Output:

Example 2: In this example, we set the filter property of the TreeSelect component to true, so it shows a sear bar on the top of the items to filter them.

• app.component.html:

HTML

<h2 style="color: green">GeeksforGeeks</h2>
<h3>
    Angular PrimeNG Form
    TreeSelect Single Component
</h3>

<p-treeSelect
    [(ngModel)]="selected"
    [filter]="true"
    [options]="nodes"
    placeholder="Select a Node">
</p-treeSelect>

• app.component.ts:

Javascript

import { Component } from "@angular/core";
import { TreeNode } from "primeng/api";

@Component({
    selector: "app-root",
    templateUrl: "./app.component.html",
})

export class AppComponent {
    nodes: TreeNode[] = [];
    selected: any;
    ngOnInit()
    {
        this.nodes = [
            {
                "label": "Work",
                "icon": "pi pi-folder",
                "children": [
                    {
                        "label": "data.json",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "sales.docx",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "presentation.pptx",
                        "icon": "pi pi-file"
                    }
                ]
            },
            {
                "label": "Home",
                "icon": "pi pi-folder",
                "children": [
                    {
                        "label": "grocery.word",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "picture.jpeg",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "homeplan.png",
                        "icon": "pi pi-file"
                    }
                ]
            },
            {
                "label": "Multimedia",
                "icon": "pi pi-folder",
                "children": [
                    {
                        "label": "infinity-war.mp4",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "you.mp3",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "endgame.mp4",
                        "icon": "pi pi-file"
                    },
                    {
                        "label": "MI.mp4",
                        "icon": "pi pi-file"
                    }
                ]
            }
        ];
    }
}

• app.module.ts:

Javascript

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { BrowserAnimationsModule }
    from '@angular/platform-browser/animations';
import { AppComponent } from './app.component';
import { FormsModule } from '@angular/forms';
import { TreeSelectModule } from 'primeng/treeselect';

@NgModule({
    imports: [
        BrowserModule,
        BrowserAnimationsModule,
        TreeSelectModule,
        FormsModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent],
})
export class AppModule { }

Output:

Reference: http://primefaces.org/primeng/treeselect