新闻阅读器 几个难点的 代码实现
一、下载RSS的xml内容，并且解析
public void UpdateArticles()
{
try
{
this.Articles.Clear();
Article art;
WebClient wc = new WebClient();
XmlDocument doc = new XmlDocument();
wc.DownloadFile(this.Url, "temp.xml");
doc.Load("temp.xml");
XmlNode docname = doc.DocumentElement;
switch (docname.Name.ToLower())
{
case "rss":
foreach (XmlNode fxn in docname.FirstChild.ChildNodes)
{
if (fxn.Name == "item")
{
art = new Article();
foreach (XmlNode sxn in fxn.ChildNodes)
{
switch (sxn.Name)
{
case "title":
art.Title = sxn.InnerText.Trim();
break;
case "link":
art.Url = sxn.InnerText.Trim();
break;
}
}
Articles.Add(art.Title, art);
}
}
break;
case "feed":
foreach (XmlNode sxn in docname.ChildNodes)
{
if (sxn.Name == "entry")
{
art = new Article();
foreach (XmlNode cxn in sxn)
{
switch (cxn.Name)
{
case "title":
art.Title = cxn.InnerText.Trim();
break;
case "link":
art.Url = cxn.Attributes["href"].Value.ToString().Trim();
break;
}
}
this.Articles.Add(art.Title, art);
}
}
break;
}
}
catch (Exception)
{
System.Windows.Forms.MessageBox.Show("请检查网络连接!");
}
}
二、持久化的存储和读取，使用序列化技术
public void Save()
{
FileStream fs = new FileStream(temp, FileMode.OpenOrCreate, FileAccess.Write);
BinaryFormatter bf = new BinaryFormatter();
bf.Serialize(fs, feed);
fs.Close();
}
public void Load()
{
try
{
if (!File.Exists(temp)) return;
FileStream fs = new FileStream(temp, FileMode.OpenOrCreate, FileAccess.Read);
BinaryFormatter bf = new BinaryFormatter();
this.feed = bf.Deserialize(fs) as List<Feed>;
fs.Close();
}
catch
{
if (this.feed == null) this.feed = new List<Feed>();
}
}