Angular 8 Cascading Dropdown

Angular 8 Cascading Dropdown Component for web applications. Dynamic and easy to use.

Table of Contents

• Getting Started
• Installation
• Usage
• Input JSON Format
• Settings
• Events
• Run locally
• Change Logs

Getting Started

Installation

• The Cascading Dropdown Dropdown package is published on the npm Registry.
• Install the package : npm install ng-cascading-dropdown-lib

Demo Url

https://swappea.github.io/ng-cascading-dropdown-lib/

Usage

Import NgCascadingDropdownLibModule into NgModule in app.module.ts. Angular's FormsModule is also required.

import { NgCascadingDropdownLibModule } from 'ng-cascading-dropdown-lib';
import { FormsModule } from '@angular/forms';

@NgModule({
  // ...
  imports: [
    NgCascadingDropdownLibModule,
    FormsModule
  ]
  // ...
})

Declare the component data variables and default options in your component where you want to consume the dropdown component.

import { Component, OnInit } from "@angular/core";

export class AppComponent implements OnInit {
  defaultTestData = [];
  defaultDropdownData = [];

  ngOnInit() {
    this.defaultTestData = [
      {
        id: 1,
        grpName: "Asia",
        parentGroupID: null
      },
      {
        id: 2,
        grpName: "North America",
        parentGroupID: null
      },
      {
        id: 3,
        grpName: "Europe",
        parentGroupID: null
      },
      {
        id: 4,
        grpName: "India",
        parentGroupID: 1
      },
      {
        id: 5,
        grpName: "Pakistan",
        parentGroupID: 1
      },
      {
        id: 6,
        grpName: "China",
        parentGroupID: 1
      },
      {
        id: 7,
        grpName: "USA",
        parentGroupID: 2
      },
      {
        id: 8,
        grpName: "Germany",
        parentGroupID: 3
      },
      {
        id: 9,
        grpName: "Maharashtra",
        parentGroupID: 4
      },
      {
        id: 10,
        grpName: "Texas",
        parentGroupID: 7
      },
      {
        id: 11,
        grpName: "Bayern",
        parentGroupID: 8
      },
      {
        id: 12,
        grpName: "Mumbai",
        parentGroupID: 9
      },
      {
        id: 13,
        grpName: "Dallas",
        parentGroupID: 10
      },
      {
        id: 14,
        grpName: "Munich",
        parentGroupID: 11
      }
    ];

    defaultDropdownData = [
      "Select Continent",
      "Select Country",
      "Select State",
      "Select City"
    ];
  }
  notifyFinalDropDownValue(event) {
    console.log("FINAL VALUE", event);
  }

  notifyDropDownValue(event) {
    console.log("ALL SELECTIONS", event);
  }
}

Add the following component tag in you template

<ng-cascading-dropdown
  [inputCascadingData]="defaultTestData"
  [defaultSelectionData]="defaultDropdownData"
  [showDefaultSelection]="true"
  [showHorizontal]="true"
  (notifyDropDownValue)="notifyDropDownValue($event)"
  (notifyFinalDropDownValue)="notifyFinalDropDownValue($event)"
>
</ng-cascading-dropdown>

Input JSON Format

• Expected JSON format is flat json heirarchy with parent and child relation maintained using parentGroupID.

Settings

The following list of settings are supported by the component. Configure the settings to meet your requirement.

Setting	Type	Description	Default Value
inputCascadingData	Array	Input Data for cascading dropdown	[ ]
defaultSelectionData	Array	Text to be show in the dropdown, when no items are selected.	[ ]
showDefaultSelection	Boolean	Show the default text for Dropdown	false
disableDropdown	Boolean	Disable the Cascading Dropdown	false
showHorizontal	Boolean	Show Cascading Dropdowns as horizontal or vertical	true

Events

• notifyDropDownValue - Returns all the selections for all dropdown Example : (notifyDropDownValue)="notifyDropDownValue($event)"
• notifyFinalDropDownValue - Return the final selected item Example : (notifyFinalDropDownValue)="notifyFinalDropDownValue($event)"

Run locally

• Clone the repository or downlod the .zip,.tar files.
• Run npm install
• Run ng serve for a dev server
• Navigate to http://localhost:4200/ The app will automatically reload if you change any of the source files.

Change Logs

v1.1.0

• Added input option to show cascading dropdown as horizontal or vertical. showHorizontal flag is used.
• Removed unused class.