Using XML To For Application Update Checker

我在自己的应用程序中做了同样的事情。

首先，在Web主机上存储一个XML文件，该文件包含更新程序信息。我的在http://getquitter.com/version.xml其结构如下：

<versioninformation>
  <latestversion>1.2.0.0</latestversion> 
  <latestversionurl>http://www.getquitter.com/quitter-1.2.0.zip</latestversionurl> 
  <filename>quitter-1.2.0.zip</filename> 
</versioninformation>

其次，编写一个从主机检索xml的方法：

Public Function GetWebPage(ByVal URL As String) As String
    Dim Request As System.Net.HttpWebRequest = CType(WebRequest.Create(New Uri(URL)), HttpWebRequest)
    With Request
        .Method = "GET"
        .MaximumAutomaticRedirections = 4
        .MaximumResponseHeadersLength = 4
        .ContentLength = 0
    End With
    Dim ReadStream As StreamReader = Nothing
    Dim Response As HttpWebResponse = Nothing
    Dim ResponseText As String = String.Empty
    Try
        Response = CType(Request.GetResponse, HttpWebResponse)
        Dim ReceiveStream As Stream = Response.GetResponseStream
        ReadStream = New StreamReader(ReceiveStream, System.Text.Encoding.UTF8)
        ResponseText = ReadStream.ReadToEnd
        Response.Close()
        ReadStream.Close()
    Catch ex As Exception
        ResponseText = String.Empty
    End Try
    Return ResponseText
End Function

接下来，调用这个方法来获取xml并加载到xml文档中。

Dim VersionInfo As New System.Xml.XmlDocument
VersionInfo.LoadXml(GetWebPage("http://www.getquitter.com/version.xml"))

加载了version.xml后，您现在可以解析出所需的各个数据片段，以确定是否需要获取新版本。

Dim LatestVersion As New Version(QuitterInfoXML.SelectSingleNode("//latestversion").InnerText)
Dim CurrentVersion As Version = My.Application.Info.Version
If LatestVersion > CurrentVersion Then
     ''download the new version using the Url in the xml
End If

我的应用程序就是这样做的。如果你想把它用作模型，你可以下载源代码(这是一个开源应用程序(。它在http://quitter.codeplex.com.希望这能有所帮助！

using System;
using System.Windows.Forms;
using System.Xml;
using System.Net;
using System.IO;
using System.Diagnostics;
namespace SAM
{
    public partial class UpdateCheck : DevExpress.XtraEditors.XtraForm
    {
        public UpdateCheck()
        {
            InitializeComponent();
            lblCurrentVersion.Text = "Current Version:  " + Application.ProductVersion;
        }
        private void MainForm_Shown(object sender, EventArgs e)
        {
            BringToFront();
        }
        public static string GetWebPage(string URL)
        {
            System.Net.HttpWebRequest Request = (HttpWebRequest)(WebRequest.Create(new Uri(URL)));
            Request.Method = "GET";
            Request.MaximumAutomaticRedirections = 4;
            Request.MaximumResponseHeadersLength = 4;
            Request.ContentLength = 0;
            StreamReader ReadStream = null;
            HttpWebResponse Response = null;
            string ResponseText = string.Empty;
            try
            {
                Response = (HttpWebResponse)(Request.GetResponse());
                Stream ReceiveStream = Response.GetResponseStream();
                ReadStream = new StreamReader(ReceiveStream, System.Text.Encoding.UTF8);
                ResponseText = ReadStream.ReadToEnd();
                Response.Close();
                ReadStream.Close();
            }
            catch (Exception ex)
            {
                ResponseText = string.Empty;
            }
            return ResponseText;
        }
        private void BtnChkUpdate_Click(object sender, EventArgs e)
        {
            System.Xml.XmlDocument VersionInfo = new System.Xml.XmlDocument();
            VersionInfo.LoadXml(GetWebPage("http://www.crimson-downloads.com/SAM/UpdateCheck.xml"));
            lblUpdateVersion.Text = "Latest Version:  " + (VersionInfo.SelectSingleNode("//latestversion").InnerText);
            textDescription.Text = VersionInfo.SelectSingleNode("//description").InnerText;
        }
        private void simpleButton2_Click(object sender, EventArgs e)
        {
            Process process = new Process();
            // Configure the process using the StartInfo properties.
            process.StartInfo.FileName = "http://www.crimson-downloads.com/SAM/Refresh.htm";
            process.StartInfo.Arguments = "-n";
            process.StartInfo.WindowStyle = ProcessWindowStyle.Maximized;
            process.Start();
        }
    }
}

简洁明了。谢谢，伙计，我在其他使用xml的东西上遇到了麻烦，但在你的帮助下，我也能够将知识应用于此，并使其发挥作用。