title: trigger NgbModal without a button but via function call
body: <p>All the examples in <a href="https://ng-bootstrap.github.io/#/components/modal/examples" rel="nofollow noreferrer">Angular Bootstrap's Modals</a> have an external button to trigger the modal itself.</p>
  
  <p>In my case I am using a Diagram, which has a function <code>nodeClicked(event, node)</code>.</p>
  
  <p>In the function I check whether the user has pressed the <kbd>CTRL</kbd> button whilst clicking the node. If not, I need to trigger a Modal stating that the button is not clicked.</p>
  
  <p><strong>component.html</strong></p>
  
  <pre><code>&lt;ng-template #content let-c="close" let-d="dismiss"&gt;
      &lt;div class="modal-header"&gt;
          &lt;h4 class="modal-title"&gt;Warning&lt;/h4&gt;
          &lt;button type="button" class="close" aria-label="Close" (click)="d('Cross click')"&gt;
              &lt;span aria-hidden="true"&gt;&amp;times;&lt;/span&gt;
          &lt;/button&gt;
      &lt;/div&gt;
      &lt;div class="modal-body"&gt;
          &lt;p&gt;NO &lt;kbd&gt;CTRL&lt;/kbd&gt; Button Pressed.&lt;/p&gt;
          &lt;p&gt;If previous Selection were selected using Multiselect Feature, they will be deleted.&lt;/p&gt;
      &lt;/div&gt;
      &lt;div class="modal-footer"&gt;
          &lt;button type="button" class="btn btn-outline-dark" (click)="c('Close click')"&gt;Close&lt;/button&gt;
      &lt;/div&gt;
  &lt;/ng-template&gt;
  </code></pre>
  
  <p>within the <code>nodeClicked()</code> function:</p>
  
  <p><strong>component.ts</strong></p>
  
  <pre><code>constructor (modal: NgbModal) {}
  ....
  nodeClicked(ev, node) {
  
  if (ev.control) {
    //perform necessary stuff
  }
  else {
    this.modal.open() // here according to API I need to pass content.
    // but I already have mentioned that in `modal-body`
  }
  
  }
  </code></pre>
  
  <p>How Can i Trigger my Modal without actually passing the <code>content</code> string in the <code>this.model.open()</code> method call?</p>