How to set/get HttpContext.Current.User.Identity.Name

Question

I created application with Ajax and Odata Services to get/insert/update the data from database.

What i want to check How to set/get HttpContext.Current.User.Identity.Name while login.

Becoz for checking/compare purpose from client side i want to check with the Odata Services.

Public Function OnQueryOrders() As Expression(Of Func(Of CustomersCall, Boolean))
Return Function(c) c.CreatedBy = HttpContext.Current.User.Identity.Name
//c.CreatedBy from DataService to compare with Current user login from client
End Function

Please help on this.

Thanks
Basit.