用反射动态创建对象，类型无法转换的困惑

企图：从XML读出节点并动态创建形成对象。
参考：http://www.cnblogs.com/Arlen/archive/2007/05/30/765506.html

工厂中的代码：

public class PublicSoftwareConfigFactory
    {
        protected Hashtable item = new Hashtable();

        public  IPublicSoftwareConfig this[PublicSoftwareConfigType type]
        {
            get
            {
                if(item.ContainsKey(type.ToString()))
                    return (IPublicSoftwareConfig)item[type.ToString()];
                else
                   return null;
            }        
        }

        public PublicSoftwareConfigFactory(string srcXML)
        {
            XmlDocument doc = new XmlDocument();
            doc.LoadXml(srcXML);
            XmlNode root = doc.DocumentElement;
            
            
            //从XML中提取对象
            foreach(PublicSoftwareConfigType softwareType in Enum.GetValues(typeof(PublicSoftwareConfigType)))
            {
                XmlNode softwareNode = root.SelectSingleNode(softwareType.ToString().ToLower());
                
                if(softwareNode == null)
                    continue;

                Assembly assembly = Assembly.LoadFrom(@"E:\webApp\Helper\arlenliu_ConfigureProj_5_int\Dsecu_Moniter_VOB\Configure\ConfigEntity\bin\Debug\Tencent.Itil.Config.ConfigEntity.dll");
                Type softwareClass = assembly.GetType("Tencent.Itil.Config.ConfigEntity.PublicSoftwareConfig." + softwareType.ToString());
                //object softwareObj = Activator.CreateInstance(softwareClass);
                object softwareObj = assembly.CreateInstance(softwareClass.FullName);

                PropertyInfo[] propArr = softwareClass.GetProperties(BindingFlags.Public | BindingFlags.Instance | BindingFlags.FlattenHierarchy);
                for(int i=0;i<propArr.Length;i++)
                {
                    XmlNode propNode = softwareNode.SelectSingleNode(propArr[i].Name.ToLower());
                    propArr[i].SetValue(softwareObj,propNode.InnerText,null);
                }
                
                if(!item.ContainsKey(softwareType.ToString()))
                    item.Add(softwareType.ToString(),softwareObj);                
            }
            
        }
        

    }

业务逻辑：

public static void ModifyProcessForPublicSoftwareConfig(string Soruce, string Operator, string DeivceId, string SoftwareXmlStr)
        {
            //根据软件配置信息XML提取公用软件配置类
            PublicSoftwareConfigFactory softwareFactory = new PublicSoftwareConfigFactory(SoftwareXmlStr);
            IPublicSoftwareConfig obj = softwareFactory[PublicSoftwareConfigType.Kernel];            
            Kernel kernel = (Kernel)obj;
}

此段中的Kernel kernel = (Kernel)obj;出错，提示无法转换。
该IPublicSoftwareConfig则是在另一个DLL中定义，而Entity中的所有实体类都继承自它，只有这样才能转换成IPublicSoftwareConfig，但是最终还是不能转换成各实体对象。

有个解决办法：将该接口可能的所有子类的属性都在接口中声明。（很明显，这个办法是很不科学的。）

最后用反序列化解决该问题。

凡事不能太钻牛角尖。