/// <summary>
/// Add a class which extends System.ValueType to this module
/// </summary>
/// <param name="attrSet">attributes of this class</param>
/// <param name="nsName">name space name</param>
/// <param name="name">class name</param>
/// <returns>a descriptor for this new class</returns>
public ClassDef AddValueClass(TypeAttr attrSet, string nsName, string name, ValueClass vClass) {
ClassDef aClass = new ClassDef(attrSet,nsName,name,metaData);
aClass.MakeValueClass(vClass);
aClass.SetTypeIndex (PrimitiveType.ValueType.GetTypeIndex ());
metaData.AddToTable(MDTable.TypeDef,aClass);
return aClass;
}