在按钮单击 angular2 上应用样式

Question

I have HTML as follows,

    <button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown" (click) aria-haspopup="true" aria-expanded="false"><span class="flag">
    </span>Spain <span class="caret"></span></button>
    <ul  class="dropdown-menu dropdown-menu-right">

On click of the above button i want to apply the following style,

.dropdown-menu
{
display :block;
}

Answer 1

basically put an ng class and set variable value on the button click.

<button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown" (click)="toggle = !toggle" aria-haspopup="true" aria-expanded="false">
    <span class="flag"></span> Spain <span class="caret"></span>
</button>
      <ul  class="dropdown-menu dropdown-menu-right" [ngClass]="{'blockStyle': toggle == true>

.blockStyle{
display :block;
  }