Nested using statements in C#

SBurris picture SBurris · Aug 25, 2009 · Viewed 94k times · Source

I am working on a project. I have to compare the contents of two files and see if they match each other precisely.

Before a lot of error-checking and validation, my first draft is:

  DirectoryInfo di = new DirectoryInfo(Environment.CurrentDirectory + "\\TestArea\\");
  FileInfo[] files = di.GetFiles(filename + ".*");

  FileInfo outputFile = files.Where(f => f.Extension == ".out").Single<FileInfo>();
  FileInfo expectedFile = files.Where(f => f.Extension == ".exp").Single <FileInfo>();

  using (StreamReader outFile = new StreamReader(outputFile.OpenRead()))
  {
    using (StreamReader expFile = new StreamReader(expectedFile.OpenRead()))
    {
      while (!(outFile.EndOfStream || expFile.EndOfStream))
      {
        if (outFile.ReadLine() != expFile.ReadLine())
        {
          return false;
        }
      }
      return (outFile.EndOfStream && expFile.EndOfStream);
    }
  }

It seems a little odd to have nested using statements.

Is there a better way to do this?

Answer

SLaks picture SLaks · Aug 25, 2009

The preferred way to do this is to only put an opening brace { after the last using statement, like this:

using (StreamReader outFile = new StreamReader(outputFile.OpenRead()))
using (StreamReader expFile = new StreamReader(expectedFile.OpenRead())) 
{
    ///...
}