title: capture property binding in angular
body: <p>I want to capture the [src] property binding to modify it with a directive and prepend with a url prefix. </p>
  
  <pre><code>&lt;img class="logo" tv-user-content [src]="config.logo" *ngIf="config !== undefined"/&gt;
  </code></pre>
  
  <p>and this directive</p>
  
  <pre><code>import { AfterContentInit, AfterViewInit, Directive, ElementRef, Input, Renderer } from '@angular/core';
  
  @Directive({
    selector: '[tv-user-content]'
  })
  export class UserContentDirective implements AfterContentInit {
  
    @Input() src: string;
  
    constructor(
      private el: ElementRef
    ) {
    }
  
    ngAfterContentInit() {
      this.el.nativeElement.setAttribute('src',"myprefix" + this.src);
    }
  }
  </code></pre>
  
  <p>is this posible?</p>