asp.net(c#)程序版本升级更新的实现代码

using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using System.IO;
using System.Net;
using System.Xml;
namespace Update
{
    /// <summary>
    /// 更新完成触发的事件
    /// </summary>
    public delegate void UpdateState();
    /// <summary>
    /// 程序更新
    /// </summary>
    public class SoftUpdate
    {
        private string download;
private const string updateUrl = "//www.jb51.net/update.xml";//升级配置的XML文件地址
        #region 构造函数
        public SoftUpdate() { }
        /// <summary>
        /// 程序更新
        /// </summary>
        /// <param name="file">要更新的文件</param>
        public SoftUpdate(string file,string softName) {
            this.LoadFile = file;
this.SoftName = softName;
        }
        #endregion
        #region 属性
        private string loadFile;
        private string newVerson;
private string softName;
        private bool isUpdate;
        /// <summary>
        /// 或取是否需要更新
        /// </summary>
        public bool IsUpdate
        {
            get
            {
                checkUpdate();
                return isUpdate;
            }
        }
        /// <summary>
        /// 要检查更新的文件
        /// </summary>
        public string LoadFile
        {
            get { return loadFile; }
            set { loadFile = value; }
        }
        /// <summary>
        /// 程序集新版本
        /// </summary>
        public string NewVerson
        {
            get { return newVerson; }
        }
/// <summary>
/// 升级的名称
/// </summary>
public string SoftName
{
get { return softName; }
set { softName = value; }
}
        #endregion
        /// <summary>
        /// 更新完成时触发的事件
        /// </summary>
        public event UpdateState UpdateFinish;
        private void isFinish() {
            if(UpdateFinish != null)
                UpdateFinish();
        }
        /// <summary>
        /// 下载更新
        /// </summary>
        public void Update()
        {
try
{
if (!isUpdate)
return;
WebClient wc = new WebClient();
string filename = "";
string exten = download.Substring(download.LastIndexOf("."));
if (loadFile.IndexOf(@"\") == -1)
filename = "Update_" + Path.GetFileNameWithoutExtension(loadFile) + exten;
else
filename = Path.GetDirectoryName(loadFile) + "\\Update_" + Path.GetFileNameWithoutExtension(loadFile) + exten;
wc.DownloadFile(download, filename);
wc.Dispose();
isFinish();
}
catch
{
throw new Exception("更新出现错误，网络连接失败！");
}
        }
        /// <summary>
        /// 检查是否需要更新
        /// </summary>
        public void checkUpdate()
        {
            try {
                WebClient wc = new WebClient();
                Stream stream = wc.OpenRead(updateUrl);
                XmlDocument xmlDoc = new XmlDocument();
                xmlDoc.Load(stream);
                XmlNode list = xmlDoc.SelectSingleNode("Update");
                foreach(XmlNode node in list) {
                    if(node.Name == "Soft" && node.Attributes["Name"].Value.ToLower() == SoftName.ToLower()) {
                        foreach(XmlNode xml in node) {
                            if(xml.Name == "Verson")
                                newVerson = xml.InnerText;
                            else
                                download = xml.InnerText;
                        }
                    }
                }
                Version ver = new Version(newVerson);
                Version verson = Assembly.LoadFrom(loadFile).GetName().Version;
                int tm = verson.CompareTo(ver);
                if(tm >= 0)
                    isUpdate = false;
                else
                    isUpdate = true;
            }
            catch(Exception ex) {
throw new Exception("更新出现错误，请确认网络连接无误后重试！");
            }
        }
        /// <summary>
        /// 获取要更新的文件
        /// </summary>
        /// <returns></returns>
        public override string ToString()
        {
            return this.loadFile;
        }
    }
}