Get reference to a directive used in a component

Question

I have a component whose template looks something like this:

<div [my-custom-directive]>Some content here</div> 

I need access to the MyCustomDirective class instance used here. When I want to get access to a child component, I use a ViewChild query.

Is there an equivalent feature to get access to a child directive?

Answer 1

You can use exportAs property of the @Directive annotation. It exports the directive to be used in the parent view. From the parent view, you can bind it to a view variable and access it from the parent class using @ViewChild().

Example With a plunker:

@Directive({   selector:'[my-custom-directive]',   exportAs:'customdirective'   //the name of the variable to access the directive }) class MyCustomDirective{   logSomething(text){     console.log('from custom directive:', text);   } }  @Component({     selector: 'my-app',     directives:[MyCustomDirective],     template: `     <h1>My First Angular 2 App</h1>      <div #cdire=customdirective my-custom-directive>Some content here</div>     ` }) export class AppComponent{   @ViewChild('cdire') element;    ngAfterViewInit(){     this.element.logSomething('text from AppComponent');   } } 

Update

As mentioned in the comments, there is another alternative to the above approach.

Instead of using exportAs, one could directly use @ViewChild(MyCustomDirective) or @ViewChildren(MyCustomDirective)

Here is some code to demonstrate the difference between the three approaches:

@Component({     selector: 'my-app',     directives:[MyCustomDirective],     template: `     <h1>My First Angular 2 App</h1>      <div my-custom-directive>First</div>     <div #cdire=customdirective my-custom-directive>Second</div>     <div my-custom-directive>Third</div>     ` }) export class AppComponent{   @ViewChild('cdire') secondMyCustomDirective; // Second   @ViewChildren(MyCustomDirective) allMyCustomDirectives; //['First','Second','Third']   @ViewChild(MyCustomDirective) firstMyCustomDirective; // First  } 

Update

Another plunker with more clarification

Answer 2

It appears that since @Abdulrahman's answer, directives can no longer be accessed from @ViewChild or @ViewChildren as these pass only items on the DOM element itself.

Instead, you must access directives using @ContentChild/@ContentChildren.

@Component({     selector: 'my-app',     template: `     <h1>My First Angular 2 App</h1>      <div my-custom-directive>First</div>     <div #cdire=customdirective my-custom-directive>Second</div>     <div my-custom-directive>Third</div>     ` }) export class AppComponent{   @ContentChild('cdire') secondMyCustomDirective; // Second   @ContentChildren(MyCustomDirective) allMyCustomDirectives; //['First','Second','Third']   @ContentChild(MyCustomDirective) firstMyCustomDirective; // First } 

There is also no longer a directives property on @Component attribute.