ASP.NET - Call event from another page

I have 2 pages : PageListAnimals and PageEditAnimal.

In PageListAnimals, there is a gridview with animals information. I can click on each animal to open the PageEditAnimal : that opens another page, in a new window.

When i finished editing animal information, i would like to save and close the window PageEditAnimal, and after that, the other window PageListAnimals will be refreshed, or the grid view inside updated.

I know solutions exist in javascript, but i would like to implement it server-side.

I think it's possible to have something like Observer pattern for example. When the PageEditAnimal is closed, that notifies the PageListAnimals to update himself.

Please give me a clue or something to help to solve that problem.

Thanks,