Service object to Export data

Hi Team,
I was going via some Razen documentation pages.
I could see on top of the Razor page the statement:
@inject NorthwindService service

How this NorthwindService defined?
In my project I have some data service classes used to access DB data.
But what exactly is this one?
I need to get the Export facility to export data from Grid to Excel.
So, in order to get the Export function how this NorthwindService class to be defined?

Thank you

Hey @Jacob_Rajan,

Maybe it will be better to get the entire project from our GitHub to see what where is defined: