"using" statement vs. curly brackets

c#, curly-braces, scope, using

Solution

Well, using (which is legal if and only if the class implements `IDisposable` interface)

using (SqlConnection conn = new SqlConnection(connString)) {
  // Some Code
  ...
}

is equal to this block of code

SqlConnection conn = null;

try {
  SqlConnection conn = new SqlConnection(connString);

  // Some Code
  ...
}
finally {
  if (!Object.ReferenceEquals(null, conn))
    conn.Dispose();
}

C# doesn't have the same behavior as C++ does, so do not use {...} pattern in C# as you do in C++:

{
  SqlConnection conn = new SqlConnection(connString);
  ...
  // Here at {...} block exit system's behavior is quite different:
  //
  // C++: conn destructor will be called, 
  // resources (db connection) will be safely freed
  //
  // C#:  nothing will have happened! 
  // Sometimes later on (if only!) GC (garbage collector) 
  // will collect conn istance and free resources (db connection). 
  // So, in case of C#, we have a resource leak 
}

Problem

I wonder why we do use `using` statement in C#. I looked it up, and found that it is used for executing the statements and then cleaning up the objects. So my question: Isn't it the same thing if we open and close curly brackets( `{ }` ) to define a scope? Using statement: ``` using (SqlConnection conn = new SqlConnection(connString)) { SqlCommand cmd = conn.CreateCommand(); cmd.CommandText = "SELECT * FROM Customers"; conn.Open(); using (SqlDataReader dr = cmd.ExecuteReader()) { while (dr.Read()) // Do Something... } } ``` Curly Brackets: ``` { SqlConnection conn = new SqlConnection(connString); SqlCommand cmd = conn.CreateCommand(); cmd.CommandText = "SELECT * FROM Customers"; conn.Open(); { SqlDataReader dr = cmd.ExecuteReader(); while (dr.Read()) // Do Something... } } ``` Are there any significant differences between two methods?

Original source