Insert record using Entityframework 3.5

See more:

C#

ASP.NET

entity-framework

I have got two tables in database

1) State (stateid,statename)

2) City(cityid, stateid, cityname)

I am using Entity framework for db manipulation

I want to insert data into City table with the reference to State Table using entity framework

For that i wrote the following code

MyModel mdl= new MyModel();
City ct=new City();

ct.cityname="Dallas";
ct.State=mdl.State.Where(u=>u.stateid==1);

mdl.AddToCity(ct);
mdl.SaveChanges();

There are data in "state" table.

But i am getting following error at "mdl.AddToCity(ct)"

"An entity object cannot be referenced by multiple instances of IEntityChangeTracker"