Question

I’ve got the following setup:

public class SomeClass
{
  private DirectoryEntry _root;
  private DirectorySearcher _searcher;

  public SomeClass()
  {
    _root = new DirectoryEntry("ldap://bla");
    _searcher = new DirectorySearcher(_root)
      {
        PageSize = int.MaxValue,
        SizeLimit = int.MaxValue
      }
  }
}

The reason I use int.MaxValue is because in this case I know I’ll exceed the defaults, but the number will never be ridiculously large, so I’m fine about that point.

But if I turn on Code Analysis and Microsoft Basic Correctness Rules it complains:

Warning 2 CA2000 : Microsoft.Reliability : In method ‘SomeClass.SomeClass()’, object ‘<>g_initLocal0′ is not disposed along all exception paths. Call System.IDisposable.Dispose on object ‘<>g_initLocal0′ before all references to it are out of scope.

It’s problem is that PageSize and SizeLimit can throw exceptions, and if that happens the G__initLocal0 object doesn’t get disposed (even if _searcher does get disposed). The exception they can throw is if you assign them to a negative number, which can’t happen here but it still complains.

Next I set the properties outside an object intitializer with regular assignment statements, but then ReSharper complains telling me that I should be using Initializer. I could suppress ReSharper, but I like to figure a way of getting things to work without adding suppressing.

So I figured I had to catch the error and I don’t like catch errors in my constructors if possible, so I created a property called Searcher like this:

private DirectorySearcher _searcher;
public DirectorySearcher Searcher
{
  get
  {
    if (_searcher != null) return _searcher;
    var searcher = new DirectorySearcher();
    try
    {
      searcher.PageSize = int.MaxValue;
      searcher.SizeLimit = int.MaxValue;
      _searcher = searcher;
    }
    catch
    {
      searcher.PageSize = 1000;
      searcher.SizeLimit = 1000;
    }
    finally
    {
      searcher.Dispose();
    }
    return _searcher;
  }
}

Now Code Analysis and everything is happy, but I’m not happy with the solution at all.

Any hints?

Answer 1

The way you are doing things now might make everyone happy but you as it wont work. You are returning a disposed DirectorySearcher in your Searcher property.

I’d just do:

public SomeClass()
{
    _root = new DirectoryEntry("ldap://bla");

    try
    {
        _searcher = new DirectorySearcher(_root);
        _searcher.PageSize = 1000;
        _searcher.SizeLimit = 1000;
    }
    catch
    {
         if (_searcher != null)
         {
             _searcher.Dispose();
         }

         throw;
    }

}

I don’t see whats wrong in using try-catch blocks in constructors.

I wouldn’t recommed the property initializer syntax when constructing IDisposable objects as you cannot dispose them normally if a property initialization throws.