Can the C# using statement be written without the curly braces?

Question

I was browsing a coworkers c# code today and found the following:

    using (MemoryStream data1 = new MemoryStream())
    using (MemoryStream data2 = new MemoryS         


        

Answer 1

If there is only one instruction which follow the statement, the bracets are not needed. It is just like with if statement.

if(true)
{
   Console.Writeline("hello")
}

means the same that

if(true)
   Console.Writeline("hello")

Answer 2

The same rules apply when you omit the curly braces in a for or an if statement.

Incidentally if you reflect into the compiled code, the compiler decompiler adds the braces.

Answer 3

Exactly what he said. The code above is exactly the same as writing:

using (MemoryStream data1 = new MemoryStream()) 
{
    using (MemoryStream data2 = new MemoryStream())
    {
        // Lots of code
    }
}

You can omit the curly braces after an if/else/for/while/using/etc statement as long as there is only one command within the statement. Examples:

// Equivalent!
if (x==6) 
    str = "x is 6";

if(x == 6) {
    str = "x is 6";
}

// Equivalent!
for (int x = 0; x < 10; ++x) z.doStuff();

for (int x = 0; x < 10; ++x) {
    z.doStuff();
}

// NOT Equivalent! (The first one ONLY wraps the p = "bob";!)
if (x == 5) 
p = "bob";
z.doStuff();

if (x == 5) {
   p = "bob";
   z.doStuff();
}

Answer 4

Exactly what your colleague said, that is the equivalent of nesting the statements. The dispose for data2 would be called immediately before the dispose function for data1.

Answer 5

As people have said: given there only being one line following a statement it will work without the curled braces. However, people are neglecting to show in their examples that that one line can be an if/using/for with it's own curled braces. Here is an example:

if(foo)
  if(bar)
  {
     doStuff();
  }

Answer 6

Yes, you can also put them in one using statement:

using (MemoryStream data1 = new MemoryStream(), 
                    data2 = new MemoryStream())
{
    // do stuff
}