Angular PrimeNG TriCheckbox Component

Angular PrimeNG is an open-source framework with a rich set 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 know how to use the TriCheckbox component in Angular PrimeNG.

TriCheckbox component: It allows a user to make a checkbox with three states ie, true, false & null conditions.

Properties:

• name: It is used to give the name of the element. It is of string data type, the default value is null.
• label: It is used to give the Label of the element. It is of string data type, the default value is null.
• disabled: It is used to disable the element. It is of the boolean datatype, the default value is false.
• tabindex: It is used to set the Index of the element in tabbing order. It is of number datatype, the default value is null.
• inputId: It is an ID identifier of the underlying input element. It is of string data type, the default value is null.
• ariaLabelledBy: It is the ariaLabelBy property that establishes relationships between the component and label(s) where its value should be one or more element IDs. It is of string data type, the default value is null.
• style: It is used to give the Inline style of the component. It is of object data type, the default value is null.
• styleClass: It is the Style class of the component. It is of string data type, the default value is null.
• readonly: it specifies that the component cannot be edited. It is of the boolean datatype, the default value is false.
• checkboxTrueIcon: It is used to set the specified icon for checkbox true value. It is of string data type, the default value is pi pi-check.
• checkboxFalseIcon: It is used to set the specifies the icon for checkbox false value. It is of string data type, the default value is pi pi-check.

Event:

• onChange: It is a callback that is fired on value change.

Styling:

• p-chkbox: It is a container element.
• p-tristatechkbox: It is a container element.
• p-chkbox-box: It is a container of the icon.
• p-chkbox-icon: It is an icon element.

Creating Angular application & module installation:

• 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: Install PrimeNG in your given directory.

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

Project Structure: It will look like the following:

Example 1: This is the basic example that shows how to use the TriCheckbox component. 

<h2>GeeksforGeeks</h2>
<h5>PrimeNG TriCheckbox component</h5>
<p-triStateCheckbox label="Enabled Checkbox"></p-triStateCheckbox>

<p-triStateCheckbox
  disabled="true"
  label="Disabled Checkbox">
</p-triStateCheckbox>

import { NgModule } from "@angular/core";
import { BrowserModule } from "@angular/platform-browser";
import { FormsModule } from "@angular/forms";
import { BrowserAnimationsModule } 
    from "@angular/platform-browser/animations";

import { AppComponent } from "./app.component";
import { TriStateCheckboxModule } 
    from "primeng/tristatecheckbox";

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

Output:

Example 2: In this example, we will know how to use readonly and style property in the triCheckbox component.

<h2>GeeksforGeeks</h2>
<h5>PrimeNG TriCheckbox component</h5>
<p-triStateCheckbox label="Enabled Checkbox"></p-triStateCheckbox>

<p-triStateCheckbox
  readonly="true"
  label="Readonly Checkbox">
</p-triStateCheckbox>

<p-triStateCheckbox
  readonly="true"
  style="border: 5px dotted">
</p-triStateCheckbox>

import { NgModule } from "@angular/core";
import { BrowserModule } from "@angular/platform-browser";
import { FormsModule } from "@angular/forms";
import { BrowserAnimationsModule } 
    from "@angular/platform-browser/animations";

import { AppComponent } from "./app.component";
import { TriStateCheckboxModule } 
    from "primeng/tristatecheckbox";

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

Output:

Reference: https://primeng.org/tristatecheckbox