In VS 2008, there is a problem with reusing collection types when you configure a WCF service and wish to “Reuse types in all refrenced assemblies”.  If you want to pass collections around via your WCF service, a Visual Studio will create a proxy class for each collection type regardless whether your collection type is included within referenced assemblies or not.  I will show you how to bypass this shortcoming.

First, locate the Reference.svcmap file for the WCF service reference you are having problems with.  If you can’t see it, ensure your project  has “Show All Files” enabled.  If you open the Reference.svcmap, you’ll find that it is written in XML.  Locate the CollectionMappings node.  Within CollectionMappings, add your collection type so when you update your service reference, it recognizes it as a known type and will not generate a proxy class for you.  Hope this helps.

   1:  <CollectionMappings>

   2:      <CollectionMapping TypeName="System.Collections.Generic.List`1" Category="List" />

   3:      <CollectionMapping TypeName="WpfApplication1.Objects.MyCollection" Category="List" />

   4:  </CollectionMappings>

Fiddler is the tool of choice when it comes to inspecting WCF messages that utilize an HTTP transport.  In a previous post I mentioned that HTTP WCF messages should be in encoded in a binary format to decrease their size.  The problem you run into when encoding your WCF messages is that when Fiddler attempts to inspect an encoded message, it’s not in a readable format.  To resolve this limitation, you can download a free plug-in which will add an inspector to Fiddler to decode binary WCF message.  Using this new inspector, you can inspect binary encoded WCF messages freely from within Fiddler.

http://code.msdn.microsoft.com/wcfbinaryinspector

Silverlight 3 offers us some new features when it comes to WCF web services.  In Silverlight 2, BasicHttpBinding was the only supported binding.  This essentially encodes your serialized objects in clear text and sends them over an HTTP transport.  Because the objects were sent as clear text, the message size could get out-of-hand.  When sending data across HTTP/Internet, you obviously want to decrease the size as this will improve performance of your client application.  Silverlight 3 offers the ability to create custom bindings which support the ability to encode your WCF web service messages as a binary format.

Binary encoding offers some serious performance gains over text encoding.  Personally I’ve seen 30% – 40% reduction in message size between the server and client when binary encoding is enabled.  Keep in mind that binary encoding is a WCF-specific feature.  Therefore if you have heterogeneous technologies wanting to consume your service, you’ll need to stick with BasicHttpBinding.  Here is an example of how to enable binary encoding for your WCF service:

   1:  <bindings>

   2:     <customBinding>

   3:        <binding name="binaryHttpBinding">

   4:           <binaryMessageEncoding />

   5:           <httpTransport />

   6:        </binding>

   7:     </customBinding>

   8:  </bindings>

   9:   

  10:  <endpoint address="" binding="customBinding" bindingConfiguration="binaryHttpBinding" contract="MyService" />