Object reference not set to an instance of an object

Question

public EFRepo(DbContext ctx)

{

this.DbContext = ctx;

this.DbConnection = ((ctx as System.Data.Entity.Infrastructure.IObjectContextAdapter).ObjectContext.Connection

as EntityConnection).StoreConnection;

this.DbSet = ctx.Set<TEntity>();

}

 

 

 In the above code 

(ctx as System.Data.Entity.Infrastructure.IObjectContextAdapter).ObjectContext.Connection

as EntityConnection

is getting null when i am changing EF 4 to 4.5