XML operations in C #

Namespace to be added:
Using System. Xml;

Define several public objects:
XmlDocument xmldoc;
XmlNode xmlnode;
XmlElement xmlelem;

1. Create an xml file in the directory with the same name as the server:

Method 1:
Xmldoc = new XmlDocument ();
// Add the Declaration section of XML
Xmlnode = xmldoc. CreateNode (XmlNodeType. XmlDeclaration ,"","");
Xmldoc. AppendChild (xmlnode );
// Add a root element
Xmlelem = xmldoc. CreateElement ("", "Employees ","");
Xmldoc. AppendChild (xmlelem );
// Add another element
For (int I = 1; I <3; I ++)
{

XmlNode root = xmldoc. SelectSingleNode ("Employees"); // find <Employees>
XmlElement xe1 = xmldoc. CreateElement ("Node"); // create a <Node> Node
Xe1.SetAttribute ("genre", "lizan red"); // you can specify the genre attribute of the node.
Xe1.SetAttribute ("ISBN", "2-3631-4"); // you can specify the ISBN attribute of the node.

XmlElement xesub1 = xmldoc. CreateElement ("title ");
Xesub1.InnerText = "CS from entry to entry"; // set a text node
Xe1.AppendChild (xesub1); // Add it to the <Node> Node
XmlElement xesub2 = xmldoc. CreateElement ("author ");
Xesub2.InnerText = "Hou Jie ";
Xe1.AppendChild (xesub2 );
XmlElement xesub3 = xmldoc. CreateElement ("price ");
Xesub3.InnerText = "58.3 ";
Xe1.AppendChild (xesub3 );

Root. AppendChild (xe1); // Add it to the <Employees> node.
}
// Save the created XML document
Xmldoc. Save (Server. MapPath ("data. xml "));

//////////////////////////////////////// ////////////

Result: A file named data. xml is generated in the directory with the same name. The content is as follows,

<? Xml version = "1.0"?>
<Employees>
<Node genre = "Li zanhong" ISBN = "2-3631-4">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
<Node genre = "Li zanhong" ISBN = "2-3631-4">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
</Employees>

Method 2:
XmlTextWriter xmlWriter;
String strFilename = Server. MapPath ("data1.xml ");

XmlWriter = new XmlTextWriter (strFilename, Encoding. Default); // create an xml document
XmlWriter. Formatting = Formatting. Indented;
XmlWriter. WriteStartDocument ();
XmlWriter. WriteStartElement ("Employees ");

XmlWriter. WriteStartElement ("Node ");
XmlWriter. WriteAttributeString ("genre", "lizanhong ");
XmlWriter. WriteAttributeString ("ISBN", "2-3631-4 ");

XmlWriter. WriteStartElement ("title ");
XmlWriter. WriteString ("CS from entry to entry ");
XmlWriter. WriteEndElement ();

XmlWriter. WriteStartElement ("author ");
XmlWriter. WriteString (" ");
XmlWriter. WriteEndElement ();

XmlWriter. WriteStartElement ("price ");
XmlWriter. WriteString ("58.3 ");
XmlWriter. WriteEndElement ();

XmlWriter. WriteEndElement ();

XmlWriter. Close ();
//////////////////////////////////////// ///////////////
Result:
<? Xml version = "1.0" encoding = "gb2312"?>
<Employees>
<Node genre = "Li zanhong" ISBN = "2-3631-4">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
</Employees>

2. Add a node:

XmlDocument xmlDoc = new XmlDocument ();
XmlDoc. Load (Server. MapPath ("data. xml "));
XmlNode root = xmlDoc. SelectSingleNode ("Employees"); // find <Employees>
XmlElement xe1 = xmlDoc. CreateElement ("Node"); // create a <Node> Node
Xe1.SetAttribute ("genre", "Zhang San"); // you can specify the genre attribute of the node.
Xe1.SetAttribute ("ISBN", "1-1111-1"); // you can specify the ISBN attribute of the node.

XmlElement xesub1 = xmlDoc. CreateElement ("title ");
Xesub1.InnerText = "C # Getting Started help"; // set a text node
Xe1.AppendChild (xesub1); // Add it to the <Node> Node
XmlElement xesub2 = xmlDoc. CreateElement ("author ");
Xesub2.InnerText = "master ";
Xe1.AppendChild (xesub2 );
XmlElement xesub3 = xmlDoc. CreateElement ("price ");
Xesub3.InnerText = "158.3 ";
Xe1.AppendChild (xesub3 );

Root. AppendChild (xe1); // Add it to the <Employees> node.
XmlDoc. Save (Server. MapPath ("data. xml "));

//////////////////////////////////////// ////////

Result: A node is added to the original xml content. The content is as follows,

<? Xml version = "1.0"?>
<Employees>
<Node genre = "Li zanhong" ISBN = "2-3631-4">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
<Node genre = "Li zanhong" ISBN = "2-3631-4">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
<Node genre = "zhangsan" ISBN = "1-1111-1">
<Title> C # Getting Started </title>
<Author> expert </author>
<Price> 158.3 </price>
</Node>
</Employees>

3. Modify the node value (attributes and subnodes ):

XmlDocument xmlDoc = new XmlDocument ();
XmlDoc. Load (Server. MapPath ("data. xml "));

XmlNodeList nodeList = xmlDoc. SelectSingleNode ("Employees"). ChildNodes; // obtain all child nodes of the Employees Node

Foreach (XmlNode xn in nodeList) // traverses all subnodes
{
XmlElement xe = (XmlElement) xn; // converts the subnode type to the XmlElement type
If (xe. GetAttribute ("genre") = "Zhang San") // if the genre attribute value is "Zhang San"
{
Xe. SetAttribute ("genre", "update Zhang San"); // modify the attribute to "update Zhang San"

XmlNodeList nls = xe. ChildNodes; // continue to obtain all the child nodes of the xe subnode
Foreach (XmlNode xn1 in nls) // traverse
{
XmlElement xe2 = (XmlElement) xn1; // Conversion Type
If (xe2.Name = "author") // if you find
{
Xe2.InnerText = "Yasheng"; // modify
}
}
}
}
XmlDoc. Save (Server. MapPath ("data. xml"); // Save.

//////////////////////////////////////// /////////////

Result: The information of all the original nodes is modified. The xml content is as follows,

<? Xml version = "1.0"?>
<Employees>
<Node genre = "Li zanhong" ISBN = "2-3631-4">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
<Node genre = "Li zanhong" ISBN = "2-3631-4">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
<Node genre = "update zhangsan" ISBN = "1-1111-1">
<Title> C # Getting Started </title>
<Author> Yasheng </author>
<Price> 158.3 </price>
</Node>
</Employees>

4. Modify the node (adding node attributes and adding the node's self-node ):

XmlDocument xmlDoc = new XmlDocument ();
XmlDoc. Load (Server. MapPath ("data. xml "));

XmlNodeList nodeList = xmlDoc. SelectSingleNode ("Employees"). ChildNodes; // obtain all child nodes of the Employees Node

Foreach (XmlNode xn in nodeList)
{
XmlElement xe = (XmlElement) xn;
Xe. SetAttribute ("test", "111111 ");

XmlElement xesub = xmlDoc. CreateElement ("flag ");
Xesub. InnerText = "1 ";
Xe. AppendChild (xesub );
}
XmlDoc. Save (Server. MapPath ("data. xml "));

//////////////////////////////////////// //////////////////////

Result: an attribute is added for each node, and a subnode is added as follows,

<? Xml version = "1.0"?>
<Employees>
<Node genre = "Li zanhong" ISBN = "2-3631-4" test = "111111">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
<Flag> 1 </flag>
</Node>
<Node genre = "Li zanhong" ISBN = "2-3631-4" test = "111111">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
<Flag> 1 </flag>
</Node>
<Node genre = "update zhangsan" ISBN = "1-1111-1" test = "111111">
<Title> C # Getting Started </title>
<Author> Yasheng </author>
<Price> 158.3 </price>
<Flag> 1 </flag>
</Node>
</Employees>

5. delete an attribute in a node:

XmlDocument xmlDoc = new XmlDocument ();
XmlDoc. Load (Server. MapPath ("data. xml "));
XmlNodeList xnl = xmlDoc. SelectSingleNode ("Employees"). ChildNodes;
Foreach (XmlNode xn in xnl)
{
XmlElement xe = (XmlElement) xn;
Xe. RemoveAttribute ("genre"); // Delete genre attributes

XmlNodeList nls = xe. ChildNodes; // continue to obtain all the child nodes of the xe subnode
Foreach (XmlNode xn1 in nls) // traverse
{
XmlElement xe2 = (XmlElement) xn1; // Conversion Type
If (xe2.Name = "flag") // if
{
Xe. RemoveChild (xe2); // Delete
}
}
}
XmlDoc. Save (Server. MapPath ("data. xml "));

//////////////////////////////////////// /// //]

Result: A node attribute and a subnode of the node are deleted as follows,

<? Xml version = "1.0"?>
<Employees>
<Node ISBN = "2-3631-4" test = "111111">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
<Node ISBN = "2-3631-4" test = "111111">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
<Node ISBN = "1-1111-1" test = "111111">
<Title> C # Getting Started </title>
<Author> Yasheng </author>
<Price> 158.3 </price>
</Node>
</Employees>

6. delete a node:
XmlDocument xmlDoc = new XmlDocument ();
XmlDoc. Load (Server. MapPath ("data. xml "));
XmlNode root = xmlDoc. SelectSingleNode ("Employees ");
XmlNodeList xnl = xmlDoc. SelectSingleNode ("Employees"). ChildNodes;
For (int I = 0; I <xnl. Count; I ++)
{
XmlElement xe = (XmlElement) xnl. Item (I );
If (xe. GetAttribute ("genre") = "Zhang San ")
{
Root. RemoveChild (xe );
If (I <xnl. Count) I = I-1;
}
}
XmlDoc. Save (Server. MapPath ("data. xml "));

//////////////////////////////////////// ////]

Result: All nodes that meet the conditions are deleted. The original content is as follows:

<? Xml version = "1.0"?>
<Employees>
<Node genre = "Li zanhong" ISBN = "2-3631-4">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
<Node genre = "Li zanhong" ISBN = "2-3631-4">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
<Node genre = "zhangsan" ISBN = "1-1111-1">
<Title> C # Getting Started </title>
<Author> expert </author>
<Price> 158.3 </price>
</Node>
<Node genre = "zhangsan" ISBN = "1-1111-1">
<Title> C # Getting Started </title>
<Author> expert </author>
<Price> 158.3 </price>
</Node>
</Employees>

Deleted content:

<? Xml version = "1.0"?>
<Employees>
<Node genre = "Li zanhong" ISBN = "2-3631-4">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
<Node genre = "Li zanhong" ISBN = "2-3631-4">
<Title> CS from entry to entry </title>
<Author> Hou Jie </author>
<Price> 58.3 </price>
</Node>
</Employees>