How to use XmlSerializer with classes produced from CompileAssemblyFromSource ?

EDN Admin · Oct 25, 2006

I dynamicaly generate code and use the CodeDomProvider and CompileAssemblyFromSource to produce an in memory Assembly. The generated code uses List<T> as one of the Properties.
I then need to stream XML into and out of a class in the in memory Assembly.
I first use the Activator to create an instance of the class: 
Assembly
Type
Activator.CreateInstance(exportedTypes[0])
The next step is to put the object in a Property Grid and fill it with data.
So far so good.
The problem occurs when i try to use the XmlSerializer to write it out as XML:
<font face="Courier New, Courier, Monospace StringWriter sw1 = new StringWriter();
 Type type = rc.GetType();
 XmlSerializer xs = new XmlSerializer(type, "Common.Generated");
 try
 {
 using (XmlTextWriter writer = new XmlTextWriter(sw1))
 {
 writer.Formatting = Formatting.Indented;
 xs.Serialize(writer, rc);
 }
 Log(sw1.ToString());

 }
 catch (Exception ex)
 {
 Log(ex.ToString());
 }
I get the following exception:
 System.TypeInitializationException: The type initializer for Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriterXXX threw an exception. ---> System.NullReferenceException: Object reference not set to an instance of an object.
 at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriterXXX..cctor()
 --- End of inner exception stack trace ---
 at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriterXXX..ctor()
 at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializerContract.get_Writer()
 at System.Xml.Serialization.TempAssembly.InvokeWriter(XmlMapping mapping, XmlWriter xmlWriter, Object o, XmlSerializerNamespaces namespaces, String encodingStyle, String id)
 at System.Xml.Serialization.XmlSerializer.Serialize(XmlWriter xmlWriter, Object o, XmlSerializerNamespaces namespaces, String encodingStyle, String id)
 --- End of inner exception stack trace ---
 at System.Xml.Serialization.XmlSerializer.Serialize(XmlWriter xmlWriter, Object o, XmlSerializerNamespaces namespaces, String encodingStyle, String id)
 at System.Xml.Serialization.XmlSerializer.Serialize(XmlWriter xmlWriter, Object o)

If I cut and past the generated code into a simple Test Program it compiles and Serializes fine, using the same code from above.
Here is a sample of the Generated Code: 
namespace Common.Generated
{
 [Serializable()]
 [XmlRoot("CONFIGURATION")]
 public class XXX
 {
 [XmlInclude(typeof(XXX.ITEM))]
 [XmlInclude(typeof(List<XXX.ITEM>))]
 [Serializable()]
 public class ITEM
 {
 public ITEM() { }
 private string NameField = String.Empty;
 [XmlElement("NAME")]
 public string Name
 {
 get { return (this.NameField); }
 set { this.NameField = value; }
 }
 }
 public XXX() { }
 private List<XXX.ITEM> items_ = new List<XXX.ITEM>();
 [XmlArray("ITEMS")]
 [XmlArrayItem("ITEM", Type=typeof(XXX.ITEM))]
 public List<XXX.ITEM> Items
 {
 get { return ( this.items_ ); }
 set { this.items_ = value; }
 }
 }
}

Here is a sample of how I am compiling the code:
 CodeDomProvider provider = CodeDomProvider.CreateProvider("CSharp");
 CompilerParameters compilerParameters = new CompilerParameters();
 compilerParameters.ReferencedAssemblies.Add("System.dll");
 compilerParameters.ReferencedAssemblies.Add("mscorlib.dll");
 compilerParameters.ReferencedAssemblies.Add("system.xml.dll");
 compilerParameters.ReferencedAssemblies.Add("system.data.dll");
 compilerParameters.ReferencedAssemblies.Add(Assembly.GetExecutingAssembly().Location);
 compilerParameters.IncludeDebugInformation = false;
 compilerParameters.GenerateExecutable = false;
 compilerParameters.GenerateInMemory = true;
 CompilerResults results = provider.CompileAssemblyFromSource(compilerParameters, _code);
 if (results.Errors.HasErrors)
 {
 Log("Error compiling assembly:");
 foreach (CompilerError error in results.Errors)
 {
 Log(error.ErrorText);
 }
 }
 else
 {
 Assembly assembly = results.CompiledAssembly;
 Type[] exportedTypes = assembly.GetExportedTypes();
 rc = Activator.CreateInstance(exportedTypes[0]);
 Log("OK");
 }
 }
Any help would be apprecieated...

 

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How to use XmlSerializer with classes produced from CompileAssemblyFromSource ?

EDN Admin

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