C # in close contact with RSS

Rss

Describes how to dynamically generate RSS files.
There are basically two ways to generate RSS files dynamically, one is to add strings to the other, and the other is to use XML document generation methods. String accumulation method is also relatively simple, I will not say more, here emphasize the generation of XmlDocument methods, including the creation of various nodes, the creation of attributes. Of course here it is also necessary to explain why the latter, because the latter conforms to the XML DOM standard, to help you understand the DOM model, and build faster, the structure of the XML document is more error-prone, some of the details I will do some of the necessary to tell.

The main methods are as follows:
private void Writerss ()
{
XmlDocument domdoc = new XmlDocument ();
XmlDeclaration nodedeclar = domdoc.createxmldeclaration ("1.0", System.Text.Encoding.UTF8.BodyName, "yes");
Domdoc.appendchild (Nodedeclar);

If the RSS has a style sheet file, add these two sentences
XmlProcessingInstruction Nodestylesheet = domdoc.createprocessinginstruction ("Xml-stylesheet", "type=\" Text/css\ " Href=\ "Rss.css\");
Domdoc.appendchild (Nodestylesheet);

XmlElement root = domdoc.createelement ("RSS");
Root. SetAttribute ("Version", "2.0"); To add a property node
Domdoc.appendchild (root);

XmlElement chnode = domdoc.createelement ("channel");
Root. AppendChild (Chnode);

XmlElement element = domdoc.createelement ("title");
XmlNode Textnode = Domdoc.createtextnode ("Sohu Focus News"); Text node
Element. AppendChild (Textnode);
Chnode. AppendChild (Element);

element = domdoc.createelement ("link");
Textnode = Domdoc.createtextnode ("http://www.sohu.com");
Element. AppendChild (Textnode);
Chnode. AppendChild (Element);

element = domdoc.createelement ("description"); Reference node
XmlNode Cdatanode = domdoc.createcdatasection ("Instant report on current affairs and global Focus events");
Element. AppendChild (Cdatanode);
Chnode. AppendChild (Element);

DataTable dt = Getdatatab (); Access the database to get the records to be displayed in RSS

foreach (DataRow dr in Dt. Rows)
{
element = Domdoc.createelement ("item");

//...
Create content nodes, common such as title,description,link,pubdate, creating methods ditto
//...

Chnode. AppendChild (Element);
}

Output
XmlTextWriter objtextwrite = new XmlTextWriter (this. RESPONSE.OUTPUTSTREAM,SYSTEM.TEXT.ENCODING.UTF8);
Domdoc.writeto (Objtextwrite);
Objtextwrite.flush ();
Objtextwrite.close ();
}

The output is as follows (the item section is added manually for the description instance):
<?xml version= "1.0" encoding= "Utf-8"?>
<rss version= "2.0" >
<channel>
<title> Sohu Focus News </title>
<link>http://www.sohu.com</link>
<description>
<! [cdata[to report on the events of global focus in China
]]>
</description>
<item id= "" >
<title></title>
<link></link>
<pubdate>2006-10-15 21:59:36</pubdate>
</item>
<item id= "" >
<title></title>
<link></link>
<pubdate>2006-10-15 10:33:53</pubdate>
</item>
<title>[intermediary [sale of residential] Ming FA International New Town 3 Room 2 Hall 2 Wei 930,000 yuan/set </title>
<link>http://www.ewhouse.com/HouseInfo.aspx?publishId=3440</link>
<pubdate>2006-10-12 10:50:18</pubdate>
</item>
</channel>
</rss>


There are a few points to note:
1, createTextNode, that is, create a text node
Some people used to use innertext to add text in the node, although the result is the same, but to know that in the DOM is also a node in Chinese, since to meet the DOM standard, it is going to the end!
2, output
I use XmlTextWriter output in the instance.
You can actually use the following:
Response.ContentType = "Application/xml"; Output and displayed as XML data
Response.Write (Domdoc.innerxml);
However, using XmlTextWriter output is faster, so this method is also recommended.

The XmlTextWriter method is implemented as follows:

XmlTextWriter writer = new XmlTextWriter (this. RESPONSE.OUTPUTSTREAM,SYSTEM.TEXT.ENCODING.UTF8);
Writer. formatting = formatting.indented;
Writer. indentation = 3;

Writer. WriteStartDocument ();

Writer. WriteComment ("Create using XmlTextWriter at" + DateTime.Now);

Writer. WriteStartElement ("RSS");
Writer. WriteAttributeString ("Version", "2.0");

Writer. WriteStartElement ("channel");
Writer. WriteElementString ("title", "Sohu Focus News");
Writer. WriteElementString ("link", "http://www.sohu.com");
Writer. Writecdata ("to report the events of international affairs at home and abroad, to interpret global focus event");

//
Middle Add access to Database section ...
//
Writer. WriteEndElement ();
Writer. WriteEndElement ();

Writer. Flush ();
Writer. Close ();

This method is the output of the XML file, if you want to save as an XML file, the first sentence in this way:
XmlTextWriter writer = new XmlTextWriter (Server.MapPath ("Grade.xml", null);