对象化数据---学习Xml Serialization的一些体会

　　刚接触.net时，就看到过一些用到XML Serialization的例子，当时没什么感觉。后来看了SDK和一些较大的程序后，逐渐有了点感觉。我个人感觉XML Serialization 的最大好处是可以将一个XML文件对象化，比如说XML中的元素、属性等都可以对应到对象、对象的属性。这样我们可以用对象的思想来操作数据，由于目前主流数据库还只是关系型的(Oracle也只是部分面向对象)，我们在数据层的操作显得于其他层面有点隔。而XML Serialization给了我们这样一个用面向对象的思维来操作数据的可能。据个例子来说，比如说我们要做一个制作工作流程的程序，每个流程有n个阶段，每个阶段有n个人来完成。如果用数据库做，就不可避免的涉及到多表关联。这对于这样一个数据量比较小的程序来说是一个浪费。我们来看一下怎么利用XML来做。

///示例XML文件
<?XML version="1.0"?>
<WorkflowData XMLns:xsi="http://www.w3.org/1999/XMLSchema-instance" XMLns:xsd="http://www.w3.org/1999/XMLSchema">
<workflows>
<workflow name="请假流程" id="1">
<stages>
<stage name="主管核准" id="1" ordernum="1">
<users>
<user name="James" isAudit="1"/>
</users>
</stage>
</stages>
</workflow>
</workflows>
</WorkflowConfigData>

///示例cs文件
using System;
using System.Collections;
using System.IO;
using System.Text;
using System.Web;
using System.XML.Serialization;

namespace Portal.Modules.Workflow
{
    public class WorkflowConfig
    {
        public static WorkflowData Settings
        {
            get
            {
                HttpContext context = HttpContext.Current;
                WorkflowData data = (WorkflowData) context.Cache["workflowconfig"];
                if (data == null)
                {
                    data = LoadSettings(WorkflowConfig.ConfigFilePath);
                    context.Cache.Insert("workflowconfig", data, new CacheDependency(WorkflowConfig.ConfigFilePath));
                }
            }
        }
        
        public static String ConfigFilePath
        {
            get
            {
                HttpContext context = HttpContext.Current;
                return context.Server.MapPath(context.Request.ApplicationPath + "//" + "Workflow//workflow.XML");
            }
        }

        public static WorkflowData LoadSettings(String fileName)
        {
            StreamReader reader = File.OpenText(fileName);
            XMLSerializer serializer = new XMLSerializer(typeof(WorkflowData));
            WorkflowData data = (WorkflowData)serializer.Deserialize(reader);
            reader.Close();
            return data;
        }

        public static void PersistSettings(WorkflowData data)
        {
            HttpContext context = HttpContext.Current;
            String configFilePath = context.Server.MapPath(context.Request.ApplicationPath + "//Workflow//workflow.XML");
            StreamWriter writer = File.CreateText(configFilePath);
            XMLSerializer serializer = new XMLSerializer(typeof(WorkflowData));
            serializer.Serialize(writer, data);
            writer.Close();
        }
    }
    
    public class WorkflowData
    {
        private Workflow[]     _workflows;

        [XMLArray]
        public Workflow [] Workflows
        {
            get
            {
                return _workflows;
            }
            set
            {
                _workflows = value;
            }
        }

        [XMLIgnore]
        public Workflow this[int workflowID]
        {
            get
            {
                foreach(Workflow workflow in Workflows)
                {
                    if(workflowID == workflow.ID)
    &nbs
更多内容请看PCdog.com--开发应用专题