This post originated from an RSS feed registered with .NET Buzz by Scott Hanselman. Original Post: Are XmlSerializers ThreadSafe? Feed Title: Scott Hanselman's ComputerZen.com Feed URL: http://radio-weblogs.com/0106747/rss.xml Feed Description: Scott Hanselman's ComputerZen.com is a .NET/WebServices/XML Weblog. I offer details of obscurities (internals of ASP.NET, WebServices, XML, etc) and best practices from real world scenarios. Latest .NET Buzz Posts Latest .NET Buzz Posts by Scott Hanselman Latest Posts From Scott Hanselman's ComputerZen.com

Here's the deal:

1. It's expensive to make XmlSerializers (until .NET 2.0 when sgen.exe comes out and I can pre-created and compile Serializers.
2. I made an XmlSerializer Factory:
   

   public class XmlSerializerFactory
   {
      private XmlSerializerFactory(){}
      private static Hashtable serializers = new Hashtable();
      public static XmlSerializer GetSerializer(Type t)
      {
         XmlSerializer xs = null;
         lock(serializers.SyncRoot)
         {
             xs = serializers[t] as XmlSerializer;
             if(xs == null)
             { 
                xs = new XmlSerializer(t);
                serializers.Add(t,xs);
             }
         }
         return xs;
       }
   }>

3. This Factory is thread safe (right?) BUT Are XmlSerializer instances ThreadSafe?  The MSDN Documentation gives the standard cop-out answer "They aren't explicitly Thread Safe..." (which means they weren't written to be, but also weren't written NOT to be)

So, to make sure I cover the case when someone is deserializing the same type of object using the SAME instance of a deserializer on multiple threads, I've been doing this:

XmlSerializer xs2 = XmlSerializerFactory.GetSerializer( >typeof(MyNamedType));
lock(xs2)
{
   mynameInstance = (MyNamedType)xs2.Deserialize(someStringReader);
}>

Is the lock{} needed? Am I being paranoid? Mr. Purdy?  Bueller?

Read: Are XmlSerializers ThreadSafe?