I understand what the using clause does, but should it be used with unnamed parameters?
For example; should:
var navigator = new XPathDocument(new StringReader(request)).CreateNavigator(); be:
using (StringReader sr = new StringReader(request)) { var navigator = new XPathDocument(sr).CreateNavigator(); ... } It makes no difference whether you are assigning the object implementing IDisposable to a variable, you should still be disposing it and hence you should use Using.
Best way to know how it works : test!
class Program { public static void Main() { using (TestDisposable d = new TestDisposable()) { } // Will trace "disposed" UseDisposable use = UseDisposable.Create(new TestDisposable()); // Will trace "disposed" } } public class UseDisposable { public TestDisposable Disposable; public static UseDisposable Create(TestDisposable disposable) { return new UseDisposable() { Disposable = disposable }; } } public class TestDisposable : IDisposable { private bool _disposed = false; #region IDisposable Membres public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } public void Dispose(bool disposing) { if(!_disposed && disposing) { Trace.WriteLine("Disposed"); _disposed = true; } } #endregion } In my opinion, you should always use the second method.
Your first code piece is equivalent to this:
StringReader sr = new StringReader(request); var navigator = new XPathDocument(sr).CreateNavigator(); The difference is that you dont create an explicit "handle" for your StringReader and therefore lose the ability to work with it later on (e.g.: disposing it).
Therefore you should be using the "using" clause. It also enhances the readability.
Yes you should use this if you can. I think the MS code analysis even warns you if you don't.
StringReader srwithout the using block.