How to pass values to directive in angular

Question

My code,

  <modal *ngIf='showModal' [imageValue]="imageId"></modal>

My model component,

@Component({
  selector: 'modal',
  templateUrl: './app/modal/modal.component.html',
  providers: [HeaderClass]
})


export class ModalComponent  {
  imageValue:any;

I want to get the value of this 'imageValue' but I dont know how to do it.Can anyone please help me.Thanks.

Solution 1

If you want to send data to directive then you should try like this:

This is my custom directive, and I am going to share two value from component or HTML to the directive.

test.directive.ts:

import { Directive, ElementRef, Input, OnInit } from '@angular/core';

@Directive({
    selector: '[input-box]'
})

export class TestDirectives implements OnInit {
    @Input() name: string;
    @Input() value: string;
    constructor(private elementRef: ElementRef) {
    }
    ngOnInit() {
        console.log("input-box keys  : ", this.name, this.value);
    }
}

and now your directive has been created and you will have add this directive into your app.module.ts like below:

app.module.ts:

import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';
import { TestDirectives } from '../directives/test.directive';


@NgModule({
  declarations: [
    AppComponent,
    TestDirectives
  ],
  imports: [],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

You will have to use your directive in your html and send data to the directive like in below code.

I am sending name and value to the test.directive.ts .

<div input-box [name]="'lightcyan'" [value]="'CYAN'"></div>

or

<div input-box [name]="componentObject.name" [value]="componentObject.value"></div>

Now see the console or use data in the directive accordingly.

Solution 2

This is an Example how you can pass value to a Directive

Directive

    import {Directive, Input, HostListener} from '@angular/core';

    @Directive({
      selector: '[appConfirm]'
    })
    export class ConfirmDirective {

      //we can also add the attribute directive liek this [appconfirm] if the input in the directive has same name as appConfirm like
      //@Input() appConfirm:string; and then in component button we can use the directive like
      //<button type="button" [appConfirm] = "Rahul">Click to Send to Directive</button>
      @Input() value:string;

      @HostListener('click',['$event'])
      confirm(){
          const confirmed = window.confirm("Are you Sure ?");
          if(confirmed){
            window.alert("This is Value ["+this.value+"] Passed by the Component to the Directive")
          }
      }

  constructor() { }

}

ComponentTemplate.html

<button type="button" appConfirm value = "Rahul">Click to Send to Directive</button>

For more info look this repo https://github.com/rahulrsingh09/AngularConcepts/tree/master/src/app/directives

Solution 3

Use @input and pass value from parent component, where this component was used like [imgval]="val"