Read and Write XML files in C #

Read:
// Open a file (assuming that web. config is in the root directory)
String filename = server. mappath ("/") + @ "webapplication1/Web. config ";
Xmldocument xmldoc = new xmldocument ();
Xmldoc. Load (filename );

// Obtain the list of top-level nodes
Xmlnodelist topm = xmldoc. documentelement. childnodes;
Foreach (xmlelement element in topm)
{
If (element. Name. tolower () = "appsettings ")
{

// Obtain the subnode of the node
Xmlnodelist nodelist = element. childnodes;

If (nodelist. Count> 0)
{
// Dropdownlist1.items. Clear ();

Foreach (xmlelement El in nodelist) // read the element value
{
// Dropdownlist1.items. Add (El. attributes ["key"]. innerxml );
// This. textbox2.text = El. attributes ["key"]. innertext;
This. textbox2.text = El. attributes ["key"]. value;
This. label1.text = El. attributes ["value"]. value;

// You can modify the element value here and save it later.
// El. attributes ["value"]. value = This. textbox2.text;
}

}

}

}

Xmldoc. Save (filename );

Add an element to a node and set the value:

If (element. Name. tolower () = "appsettings ")
{

Xmlelement ELEM = xmldoc. createelement ("add ");

Element. appendchild (ELEM );
ELEM. innertext = "LTP ";

Xmldoc. Save (filename );

}

Effect:
<Deleetask>
<Add key = "password" value = "admin"/>
<Add> LTP </Add>
</Appsettings>

Add an element under a node and add two attributes:
If (element. Name. tolower () = "appsettings ")
{

Xmlelement ELEM = xmldoc. createelement ("add ");
Element. appendchild (ELEM );

Xmlattribute XA = xmldoc. createattribute ("key ");
Xa. value = "LTP ";

Xmlattribute xa2 = xmldoc. createattribute ("value ");
Xa2.value = "first ";

ELEM. setattributenode (xa );
ELEM. setattributenode (xa2 );

Xmldoc. Save (filename );

}

Effect:
<Deleetask>
<Add key = "password" value = "admin"/>
<Add key = "LTP" value = "first"/>
</Appsettings>

// Add an empty element:
Xmlnode node = Doc. createelement (groupname );
Node. innertext = "";
Doc. lastchild. appendchild (node );

Doc. Save (xmlfile );

Delete a node Element
String itemname = This. listbox1.selecteditem. tostring ();

This. listbox1.items. Remove (this. listbox1.selecteditem );

// Begin del xmlfile
Xmldocument Doc = new xmldocument ();
Doc. Load (xmlfile );

Xmlnodelist topm = Doc. documentelement. childnodes;
Foreach (xmlelement element in topm)
{
If (element. Name = This. combobox1.text)
{

// Obtain the subnode of the node
Xmlnodelist nodelist = element. childnodes;

Foreach (xmlelement El in nodelist) // read the element value
{
If (El. attributes ["key"]. value = itemname)
{
Element. removechild (EL );
}

} // Cyclic Element

} // Get the group

} // Cycle Group

Doc. Save (xmlfile); // be sure to save it; otherwise, it will not work.

// Filter data
Private void reader_xml (string pathflie)
{
Xmldocument xmldoc = new xmldocument ();
Xmldoc. Load (pathflie );
Xmlnodelist record1 = xmldoc. documentelement. selectnodes (code [@ ID = '1'])
Int f = 0;
Foreach (xmlnode xnode in record1)
{

}
}/** // * Two XML methods for reading XML data */
<AAA>
<BB> something </BB>
<CC> something </CC>
</AAA>

<AAA>
<Add key = "123" value = "321"/>
</AAA>

/** // * Method 1 */
DS. readxml ("Your xmlfile name ");
Container. dataitem ("BB ");
Container. dataitem ("cc ");
DS. readxmlschema ("Your xmlfile name ");

/** // * Method 2 */
<AAA>
<Add key = "123" value = "321"/>
</AAA>
What should I do if I want to find 123 and get 321?

Using system. xml;
Xmldatadocument xmldoc = new system. xml. xmldatadocument ();
Xmldoc. Load (@ "C:/config. xml ");
Xmlelement ELEM = xmldoc. getelementbyid ("add ");
String STR = ELEM. attributes ["value"]. Value

/** // * Method 3: selectsinglenode reads XML in two formats *---/
--------------------------------------------------------------------
<? XML version = "1.0" encoding = "UTF-8"?>
<Configuration>
<Deleetask>
<Connectionstring> Data Source = YF; user id = ctm_dbo; Password = 123 </connectionstring>
</Appsettings>
</Configuration>
--------------------------------------------------------------------------
Xmldocument Doc = new xmldocument ();
Doc. Load (strxmlname );

Xmlnode node = Doc. selectsinglenode ("/configuration/etettings/connectionstring ");
If (node! = NULL)
{
String k1 = node. value; // null
String k2 = node. innertext; // data source = YF; user id = ctm_dbo; Password = 123
String K3 = node. innerxml; // data source = YF; user id = ctm_dbo; Password = 123
Node = NULL;
}

**************************************** ****************************
<? XML version = "1.0" encoding = "UTF-8"?>
<Configuration>
<Deleetask>
<Add key = "connectionstring" value = "Data Source = YF; user id = ctm_dbo; Password = 123"/>
</Appsettings>
</Configuration>
**--------------------------------------------------------------------**
Xmlnode node = Doc. selectsinglenode ("/configuration/etettings/Add ");
If (node! = NULL)
{
String K = node. attributes ["key"]. value;
String v = node. attributes ["value"]. value;
Node = NULL;
}
*--------------------------------------------------------------------*
Xmlnode node = Doc. selectsinglenode ("/configuration/etettings/Add ");
If (node! = NULL)
{
Xmlnodereader Nr = new xmlnodereader (node );
Nr. movetocontent ();
// Check whether the current node is a content node. If this node is not a content node, the reader jumps forward to the next content node or the end of the file.
Nr. movetoattribute ("value ");
String S = Nr. value;
Node = NULL;
}