title: Error: TypeError: Cannot read property 'c' of undefined
body: <p>I am working on google charts with angularjs. My functionality is working fine, but issue is when i click on the legend it is throwing the error which can be seen in the browser console and i know the error is causing because of the below code :</p>
  
  <pre><code>$scope.serverId = chart1.data.rows[selectedItem.row].c[3].v;
  alert("serverid : " + $scope.serverId);
  </code></pre>
  
  <p>The above code is required to get the assigned server ID when user click on any of the line in the chart and it is returning the ID, issue is when user click on the legend, it has to disable the corresponding line in the chart and when this scenario is tested i can see the error in the browser console. Any inputs how to resolve that error ?? </p>
  
  <pre><code>TypeError: Cannot read property 'c' of undefined
      at $$childScopeClass.$scope.seriesSelected
  </code></pre>
  
  <p>I still want the code to get the serverID. <a href="https://plnkr.co/edit/j0eP0UsjTzudUQ5IJGIN?p=preview" rel="nofollow noreferrer">Click here</a> for demo. Please click on the tip of the lines in the demo plunker to notice the alert and when clicked on the legend you can notice the error in the browser console.</p>