Question

Is it ok to instance a MemoryStream at the top of my method, do a bunch of stuff to it, and then use it?

For instance:

public static byte[] TestCode()
{
  MemoryStream m = new MemoryStream();
  ...
  ...
  whole bunch of stuff in between
  ...
  ...

  //finally

  using(m)
  {
     return m.ToArray();
  }
}

Updated code

public static byte[] GetSamplePDF()
{
    using (MemoryStream m = new MemoryStream())
    {
        Document document = new Document();

        PdfWriter.GetInstance(document, m);

        document.Open();

        PopulateTheDocument(document);

        document.Close();

        return m.ToArray();
    }
}

private static void PopulateTheDocument(Document document)
{
    Table aTable = new Table(2, 2);
    aTable.AddCell("0.0");
    aTable.AddCell("0.1");
    aTable.AddCell("1.0");
    aTable.AddCell("1.1");

    document.Add(aTable);

    for (int i = 0; i < 20; i++)
    {
        document.Add(new Phrase("Hello World, Hello Sun, Hello Moon, Hello Stars, Hello Sea, Hello Land, Hello People. "));
    }

}

My point was to try to reuse building the byte code. In other words, build up any kind of document and then send it to TestCode() method.

Answer 1

Technically, this is possible, but it’s pointless. If you really want to avoid using the “using” statement around that code, just call Dispose() directly.

You should put the entire work that’s using the MemoryStream into the using statement. This guarantees that the MemoryStream’s Dispose method will be called, even if you receive an exception during your “whole bunch of stuff in between” code. The way you have it now, exceptions will prevent your MemoryStream from having Dispose() called on it.

The proper way to handle this would be:

public static byte[] TestCode()
{
  MemoryStream m = new MemoryStream();
  using(m)
  {
      // ...
      // ...
      // whole bunch of stuff in between
      // ...
      // ...

     return m.ToArray();
  }
}

Or, in the more common form:

public static byte[] TestCode()
{
  using(MemoryStream m = new MemoryStream())
  {
      // ...
      // ...
      // whole bunch of stuff in between
      // ...
      // ...

     return m.ToArray();
  }
}