public int testCon()
    {
        using (SqlConnection conn = new SqlConnection("Conn string"))
        {
            using (SqlCommand cmd = conn.CreateCommand())
            {
                conn.Open();
                cmd.CommandText = "SELECT COUNT(1) FROM Carsd";

                return (int)cmd.ExecuteScalar();
            }
        }
    }

class Program
{
    static void Main(string[] args)
    {
        testDispose objTestDispose;

        using (objTestDispose = new testDispose())
        {
            objTestDispose.UserName = "testUser";
            objTestDispose.PassWord = "testPassword";
        }

        Console.WriteLine("Check obj of testDispose Class" + objTestDispose.UserName);
        Console.WriteLine("Check obj of testDispose Class" + objTestDispose.PassWord);
        Console.ReadLine();

    }
}

public class testDispose : IDisposable
{
    public string UserName { get; set; }
    public string PassWord { get; set; }

    public void Dispose()
    { }
}