ng-include allows you to delegate the control of one part of the page to a specific controller. You may want to do this because the complexity of that component is becoming such that you want to encapsulate all the logic in a dedicated controller.
An example is:
Note that the /gridview will need to be served by the web server as a distinct and legitimate url.
Also, note that the src-attribute accepts an Angular expression. This could be a variable or a function call for example or, like in this example, a string constant. In this case you need to make sure to wrap the source URL in single quotes, so it will be evaluated as a string constant. This is a common source of confusion.
Within the /gridview html, you can refer to the gridController as if it were wrapped around the page, eg: