What scope does a using statement have without curly braces

Question

I inherited the following code:

    using (var dataAccessConnection = da.GetConnection()) //no opening curly brace here
    using (var command = new SqlCommand(sql, dataAccessConnection.Connection))
    {
        command.CommandType = CommandType.Text;
        using (var sqlDataReader = command.ExecuteReader(CommandBehavior.CloseConnection))
        {
            while (sqlDataReader.Read())
            {
                rueckgabe.Add(new Myclass
                                  {
                                      Uid = Guid.NewGuid(),
                                      ImportVersionUid = versionUid,
                                      MyProperty = Convert.ToInt32(sqlDataReader["MyProperty"])
                                        });       
            }
        }
        command.Connection.Close();
        dataAccessConnection.Connection.Close();
    }

Looking at the code I expexted an opening curly brace after the using clause.

The code compiles and does what it is expected to do. The application behaves unpredictable. At some time it cant access the Database server.

Does this code make sense? Does dataAccessConnection have the rigth scope?

Answer 1

Beginning with C# 8.0, the using keyword can be used as an attribute in the variable declarations of disposable objects (Reference). The semantics is as you would expect -- the objects are auto-disposed at the end of the scope.

        public class Disposable : IDisposable
        {
            string name;

            public Disposable(string name)
            {
                this.name = name;
            }

            public void Dispose()
            {
                Console.WriteLine(name + " disposed");
            }

            public void Identify()
            {
                Console.WriteLine(name);
            }

            static void Main(string[] args)
            {
                using Disposable d1 = new Disposable("Using 1");
                Disposable d2 = new Disposable("No Using 2");
                using Disposable d3 = new Disposable("Using 3");
                Disposable d4 = new Disposable("No Using 4");
                d1.Identify();
                d2.Identify();
                d3.Identify();
                d4.Identify();
            }
        }

Output

Using 1
No Using 2
Using 3
No Using 4
Using 3 disposed
Using 1 disposed