Can't access localdb with connection string

Hi! I have installed VS2010 with framework 4.0.3.$0 In my WinForm application I used the following connection string but failed to connection:$0 Server=(localdb)\v11.0;Integrated Security=true;Database=TestDB;$0 $0 The error message is: $0 System.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Ser