C# Setting XmlSerializer options correctly?

My XmlSerializer code is outputting Xml that is much more verbose than I require, how can I control the output settings properly? This is the code:

var stream = new MemoryStream()开发者_StackOverflow社区;
var xmlSerializer = new XmlSerializer(objectToSerialize.GetType());            
xmlSerializer.Serialize(stream, objectToSerialize);
string xml = encoding != null ? encoding.GetString(stream.ToArray()) 
                              : Encoding.Default.GetString(stream.ToArray());

And the output looks like this:

<?xml version="1.0"?>
<ArrayOfProduct xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Product>
    <Id>1</Id>
    <ProductCode>A</ProductCode>
    <ProductDescription>Product A</ProductDescription>
    <Obsolete xsi:nil="true"></Obsolete>
  </Product>
</ArrayOfProduct>

I want to be able to format the Xml like so:

• Remove the xsi:nil="true" from lines with no value
• Collapse empty tags like <Obsolete></Obsolete> into the simple form <Obsolete />

When you decorate the class and members using [Serializable] the objects are serialized using the old methods which does not contains xsi:nil="true But when you decorate the class with [DataContract] attribute the XmlSerializer will include the xsi:nil="true.

One way to remove xsi:nil="true is to decorate the class with [Serializable] attribute.