Silverlight json won't serialize

I have been trying to serialize some json data in Silverlight. I am using the following code

System.Runtime.Serialization.Json.DataContractJsonSerializer serializer = new System.Runtime.Serialization.Json.DataContractJsonSerializer(stacks.GetType());
MemoryStream ms = new MemoryStream();
serializer.WriteObject(ms, stacks);
StreamReader reader = new StreamReader(ms);
string json = reader.ReadToEnd();

to attempt the serialization. It does not work. It was the only example I could find that did not produce errors in Visual Studio. I am passing a list of custom coded object开发者_如何学Cs (stacks). When I try to view the results I am getting a blank string. Anyone got some ideas on how to point me in the right direction?

The stream cursor is pointing to the end (after everything was written). Add the line "ms.Position = 0;" before creating the StreamReader.