How to implement a web service that respond in json?

Question

Hi All,

I am trying to display data from my MSSQL Server table into ExtJS grid. I am trying to write a webmethod in C# to connect to the database,execute the query and get the table data as JSON format to display it in the ExtJS grid.
I am just starting using C# and not experienced on it. I will be quite glad if anybody can share an example of a C# for gnerating JSON data from MSSQL Server.

Thanks a lot

Asim