How do I set the "ExpandebleRow" property in the ui-grid?

I am using ui-grid to display grid and subnet for each row. When the parent grid is loaded, it shows the "+" symbol, but does not expand when the "+" is pressed. I can expand the grid as soon as the page is redirected after the parent grid has loaded. After investigating, I found that the expandableRow property is not angular for the parent row of the grid. This property is only set after page reload.

How can I set this from my typescript code? Will this conflict with existing angular code?