. NET operations XML file (Add. Modify, delete, read) __.net

 There is a requirement today to manipulate an XML node. Suddenly see a lot of forgotten. The internet has read some information. The head is really not enough. I'll share the information I found here. This article belongs to the net pick/
 

1  first, Brief introduction 2 using system.xml;
3 //Initializes an XML instance 4 xmldocument xml=new xmldocument (); 5 //Import the specified XML file 6 xml.
Load (path); 7 xml.
Load (HttpContext.Current.Server.MapPath ("~/file/bookstore.xml")); 8 //Specifies a node 9 xmlnode root=xml.
selectSingleNode ("/root"); 10 //gets all the direct child nodes under the node 11 xmlnodelist childlist=root.
ChildNodes; 12 //determine if there is a child node under the node 13 root.
HasChildNodes; 14 //gets the same sibling node collection 15 xmlnodelist nodelist=xml with the same name.
SelectNodes ("/root/news");
16 //generates a new node 17 xmlelement node=xml.createelement_x ("News"); 18 //the node to the specified node as its child node 19 root.
AppendChild (node); 20 //adds a node to 21 root before a child node under the specified node. InsertBefore (Node,root.
Childenodes[i]); 22 //the new attribute for the specified node and assigns a 23 node value.
SetAttribute ("id", "11111"); 24 //adds a child node 25 root to the specified node.
AppendChild (node); 26 //gets the specified property value 27 string id=node for the specified node. attributes["id"].
Value; 28 //gets the text 29 string content=node in the specified node.
InnerText; 30 //Save XML file 31 string path=server.mappath ("~/file/bookstore.xml"); 32 xml.
Save (path); 33 //or Use:xml. Save (HttpContext.Current.Server.MapPath ("~/file/bookstore.xml"));  34  II, concrete instance 35  how to manipulate XML 36 in C#.net
  Namespaces to add: 37 using system.xml;
38  defines several common objects: 39 xmldocument xmldoc;
40 xmlnode XmlNode;
41 xmlelement Xmlelem;
42 1, create an XML file to the server directory with the same name: 43  44  method One: 45 xmldoc = new xmldocument ();
46 //joins the declaration paragraph of XML, <?xml version= "1.0" encoding= "gb2312"?> 47 xmldeclaration; 48 xmldecl = xmldoc.
Createxmldeclaration ("1.0", "gb2312", null); 49 xmldoc.
AppendChild (XMLDECL); 50 //Add a root element 51 xmlelem = xmldoc.createelement_x (  ""  ,  "Employees"  ,  " )
; 52 xmldoc.
AppendChild (Xmlelem); 53 //adds another element 54 for (int i=1;i<3;i++) 55 {56 xmlnode Root=xmldoc. selectSingleNode ("Employees")/Find <Employees>  57 xmlelement xe1=xMldoc.createelement_x ("node");//Create a <Node> node   58 xe1. SetAttribute ("Genre", "Li Zhanhong");/set the node genre properties   59 xe1. SetAttribute ("ISBN", "2-3631-4");/set this node ISBN property 60 xmlelement xesub1=xmldoc.createelement_x ("title");  61  xesub1. Innertext= "CS from entry to Mastery";/Set text node   62&NBSP;XE1.
AppendChild (XESUB1);//Add to <Node> node   63 xmlelement xesub2=xmldoc.createelement_x ("author");  64 xesub2. innertext= "Hou Jie";  65 xe1. AppendChild (XESUB2);  66 xmlelement xesub3=xmldoc.createelement_x ("price");  67 xesub3. innertext= "58.3";  68 xe1.
AppendChild (XESUB3); 69 root. AppendChild (XE1);//Add to <Employees> node   70&NBSP} 71 //Save the created XML document 72 xmldoc.
Save (Server.MapPath ("Data.xml")); 73//////////////////////////////////////////////////////////////////////////////////////74  Results: A file named Data.xml was generated under the same directory, with the following contents, 75 <?xml version= "1.0"  encoding= "gb2312"?> 76 <employees > 77 &Lt Node genre= "Li Zhanhong"  isbn= "2-3631-4" > 78 <title>cs from Entry to Mastery </title> 79 <author> Hou Jie </author> 80 <price>58.3</price> 81 </node> 82 <node genre= "李赞红"   isbn= "2-3631-4" > 83 <title>cs from entry to proficiency </title> 84 <author> Hou Jie </author> 85  <price>58.3</price> 86 </node> 87 </employees> 88  89  Method II: 90 
xmltextwriter xmlwriter;
91 string strfilename = Server.MapPath ("Data1.xml"); 92 xmlwriter = new xmltextwriter (Strfilename,encoding.default);//Create an XML document 93 
xmlwriter.formatting = formatting.indented;
94 xmlwriter.writestartdocument ();
95 xmlwriter.writestartelement ("Employees");
96 xmlwriter.writestartelement ("Node");
97 xmlwriter.writeattributestring ("Genre", "Li Zhanhong");
98 xmlwriter.writeattributestring ("ISBN", "2-3631-4");
99 xmlwriter.writestartelement ("title"); 100 xmlwriter.wrItestring ("CS from Introduction to proficiency");
101 xmlwriter.writeendelement ();
102 xmlwriter.writestartelement ("author");
103 xmlwriter.writestring ("Hou Jie");
104 xmlwriter.writeendelement ();
105 xmlwriter.writestartelement ("Price");
106 xmlwriter.writestring ("58.3");
107 xmlwriter.writeendelement ();
108 xmlwriter.writeendelement ();
109 xmlwriter.close (); 110//////////////////////////////////////////////////////////////////////////////////////111  Results: 112  <?xml version= "1.0"  encoding= "gb2312"?> 113 <employees> 114 <node genre= "李赞红"   isbn= "2-3631-4" > 115 <title>cs from entry to proficiency </title> 116 <author> Hou Jie </author> 117  <price>58.3</price> 118 </node> 119 </employees> 120 2, add a node: 121
 xmldocument xmldoc=new xmldocument ();  122 xmldoc.load (Server.MapPath ("Data.xml"));  123 xmlnode Root=xmldoc.selectsinglenode ("Employees");/Find <employees>  124 xmlelement xe1=xmldoc.createelement_x ("node");//Create a <Node> node   125&NBSP;XE1 . SetAttribute ("Genre", "John");/set the node genre properties   126 xe1. SetAttribute ("ISBN", "1-1111-1");/set the Node ISBN property 127 xmlelement xesub1=xmldoc.createelement_x ("title");   128&NBSP;XESUB1. Innertext= "C # Getting Started help";//Setting up text nodes   129 xe1. AppendChild (XESUB1);//Add to <Node> node   130 xmlelement xesub2=xmldoc.createelement_x ("author");   131&NBSP;XESUB2. innertext= "Master";  132 xe1. AppendChild (XESUB2);  133 xmlelement xesub3=xmldoc.createelement_x ("price");  134 xesub3. innertext= "158.3";  135 xe1.
AppendChild (XESUB3); 136 root.
AppendChild (XE1);//Add to <Employees> node   137 xmldoc.save (Server.MapPath ("Data.xml")); 138//////////////////////////////////////////////////////////////////////////////////////139  Results: A node is added to the original content of XML, and the contents are as follows, 140 <?xml version= "1.0"  encoding= "gb2312"?> 141 &Lt
employees> 142 <node genre= "Li Zhanhong"  isbn= "2-3631-4" > 143 <title>cs from Getting started to mastering </title> 144 <author> </author> 145 <price>58.3</price> 146 </node> 147  <node genre= "Li Zhanhong"  isbn= "2-3631-4" > 148 <title>cs from Entry to Mastery </title> 149 < author> </author> 150 <price>58.3</price> 151 </node> 152 <node Genre= "John"  isbn= "1-1111-1" > 153 <title>c# Introductory Help </title> 154 <author> master </ author> 155 <price>158.3</price> 156 </node> 157 </employees> 158  3, modify the node values (attributes and child nodes): 159 xmldocument xmldoc=new xmldocument ();  160 xmldoc.load (Server.MapPath ("
Data.xml ")); 161 xmlnodelist Nodelist=xmldoc.selectsinglenode ("Employees"). childnodes;//gets all child nodes of the Employees node 162 foreach (XmlNode xn in nodelist)//traverses all child nodes   163 {   164 xmlelement XE= (XmlElement) xn;//Converts a child node type to a XmlElement type   165 if (XE. GetAttribute ("genre") = = "John")//If genre property value is "John"   166 {  167 xe. SetAttribute ("Genre", "Update John");//Modify this property to "update John" 168 xmlnodelist Nls=xe. CHILDNODES;//continues to fetch all child nodes of the XE child node   169 foreach (XmlNode xn1 in nls)/traversal   170 {  171  xmlelement xe2= (XmlElement) xn1;//conversion type   172&NBSP;IF (xe2. name== "Author")//If found   173 {  174 xe2. innertext= "Ya sheng";//Modify 175 }  176 }  177 }  178 }  179 xmldoc.save (
Server.MapPath ("Data.xml"))//save. 180//////////////////////////////////////////////////////////////////////////////////////181  Result: The information of all the original nodes has been modified, the contents of XML are as follows, 182 <?xml version= "1.0"  encoding= "gb2312"?> 183 <employees > 184 <node genre= "Li Zhanhong"  isbn= "2-3631-4" > 185 <title>cs from Getting Started to mastering </title> 186  <author> Hou Jie </author> 187 <price>58.3</price> 188 </node> 189 <node genre= "Li Zhanhong"  isbn= "2-3631-4" > 190 <title>cs from entry to Mastery </ title> 191 <author> </author> 192 <price>58.3</price> 193 </node > 194 <node genre= "Update John"  isbn= "1-1111-1" > 195 <title>c# Getting Started help </title> 196  <author> Asia wins </author> 197 <price>158.3</price> 198 </node> 199 
</Employees> 200 4, modify the node (Add node properties and add nodes from the node): 201 xmldocument xmldoc=new xmldocument (); 
202 xmldoc.load (Server.MapPath ("Data.xml")); 203 xmlnodelist Nodelist=xmldoc.selectsinglenode ("Employees"). childnodes;//gets all the subnodes of the Employees Node 204 foreach (XmlNode xn in nodelist)   205 {  206  xmlelement xe= (XmlElement) xn;  207 xe.
SetAttribute ("Test", "111111"); 208 xmlelement xesub=xmldoc.createelement_x ("flag");  209 xesub. innertext= "1";  210 xe. AppendChild (XESub);  211 }  212 xmldoc.save (Server.MapPath ("Data.xml")); 213//////////////////////////////////////////////////////////////////////////////////////214  Result: The attributes of each node are added one, and the child nodes are added as follows, 215 <?xml version= "1.0"  encoding= "gb2312"?> employees> 217 <node genre= "Li Zhanhong"  isbn= "2-3631-4"  test= "111111" > 218 <title> CS from getting started to proficient </title> 219 <author> </author> 220 <price>58.3</price> 221  <flag>1</flag> 222 </node> 223 <node genre= "Li Zhanhong"  isbn= "2-3631-4"   test= "111111" > 224 <title>cs from entry to proficiency </title> 225 <author> Hou Jie </author> 226  <price>58.3</price> 227 <flag>1</flag> 228 </node> 229 <node Genre = "Update John"  isbn= "1-1111-1"  test= "111111" > 230 <title>c# Getting Started help </title> 231 < Author> </author> 232 <price>158.3</price> 233 <flag>1</flag> 234 </node> 235 </Employees> 236 5, delete one of the properties in the node: 237 xmldocument xmldoc=new xmldocument ();  238 xmldoc.load ( Server.MapPath ("Data.xml"));  239 xmlnodelist xnl=xmldoc.selectsinglenode ("Employees"). childnodes;  240 foreach (XmlNode xn in xnl)   241 {  242 xmlelement xe= ( XmlElement) xn;  243 xe. RemoveAttribute ("genre");//Delete genre property 244 xmlnodelist Nls=xe. CHILDNODES;//continues to fetch all child nodes of the XE child node   245 foreach (XmlNode xn1 in nls)/traversal   246 {  247  xmlelement xe2= (XmlElement) xn1;//conversion type   248&NBSP;IF (xe2. name== "flag")//If found   249 {  250 xe. RemoveChild (XE2);//delete 251 }  252 }  253 }  254 xmldoc.save ("
Data.xml ")); 255//////////////////////////////////////////////////////////////////////////////////////] 256  Result: Delete One of the attributes of the endpoint and one of the nodesThe child node, the contents are as follows, 257 <?xml version= "1.0"  encoding= "gb2312"?> 258 <employees> 259 < Node isbn= "2-3631-4"  test= "111111" > 260 <title>cs from Getting Started to mastering </title> 261 <author> Hou Jie </author> 262 <price>58.3</price> 263 </node> 264 <node ISBN= "2-3631-4
" test=" 111111 > 265 <title>cs from entry to proficiency </title> 266 <author> Hou Jie </author> 267 <price>58.3</price> 268 </node> 269 <node ISBN= "1-1111-1"  test= " 111111 "> 270 <title>c# Getting Started help </title> 271 <author> </author> 272 < Price>158.3</price> 273 </node> 274 </employees> 275 6, delete node: 276  XmlDocument xmldoc=new xmldocument ();  277 xmldoc.load (Server.MapPath ("Data.xml"));  278
 xmlnode Root=xmldoc.selectsinglenode ("Employees"); 279 xmlnodelist Xnl=xmldoc.selectsinglenode ("Employees"). childnodes;  280 for (int i=0;i<xnl. count;i++) 281 {282 xmlelement xe= (XmlElement) xnl. Item (i);  283 if (XE. GetAttribute ("genre") = = "John")   284 {  285 root.
RemoveChild (XE); 286 if (I&LT;XNL.
Count) i=i-1;
287 }  288 } 289 xmldoc.save (Server.MapPath ("Data.xml")); 290//////////////////////////////////////////////////////////////////////////////////////] 291  Results: Delete all the nodes that match the condition, the original content: 292 <?xml version= "1.0"  encoding= "gb2312"?> 293 <employees> 294  <node genre= "Li Zhanhong"  isbn= "2-3631-4" > 295 <title>cs from Entry to Mastery </title> 296 < author> </author> 297 <price>58.3</price> 298 </node> 299 <node Genre= "Li Zhanhong"  isbn= "2-3631-4" > 300 <title>cs from entry to proficiency </title> 301 <author> Hou Jie </ author> 302 <price>58.3</price> 303 </node> 304 <node genre= "John"  ISBN= "1-1111-1" > 305 <title>c# Introductory Help </title> 306 <author> master </author> 307 < price>158.3</price> 308 </node> 309 <node genre= "John"  isbn= "1-1111-1" > 310  <title>c# Getting Started help </title> 311 <author> master </author> 312 <price>158.3< /price> 313 </node> 314 </employees> 315  deleted content: 316 <?xml version= "1.0"  encoding= "gb2312"?> 317 <employees> 318 <node genre= "Li Zhanhong"  isbn= "2-3631-4" > 319  <title>cs from getting started to proficient </title> 320 <author> </author> 321 <price>58.3 </price> 322 </node> 323 <node genre= "Li Zhanhong"  isbn= "2-3631-4" > 324 <title >cs from entry to Mastery </title> 325 <author> </author> 326 <price>58.3</price> 327  </Node> 328 </employees> 329 7, reading XML by text file 330 system.io.streamreader myFile =new  331 system.io.streamreader (Server.MapPath ("Data.xml"), System.Text.Encoding.Default); 332 //Note System.Text.Encoding.Default 333 string mystring = Myfile.readtoend ();//mystring is read out string 334
 myfile.close (); 335  336  III, advanced applications   337  338 <aaa> 339 <bb>something</bb> 340  <cc>something</cc> 341 </aaa> 342  343 <aaa> 344 <add key= "123"  value= "321"/> 345 </aaa> 346  347 ds.
READXML ("Your xmlfile name");
348 container.dataitem ("BB");
349 container.dataitem ("CC"); 350 ds.
ReadXmlSchema ("Your xmlfile name"); 351  352  353 <aaa> 354 <add key= "123"  value= "321"/> 355 </aaa> 356
  What should I write if I have to find 123 and then get 321?
357  358 using system.xml;
359 xmldatadocument xmldoc = new system.xml.xmldatadocument ();
360 xmldoc.load (@ "C:\Config.xml"); 361 xmlelement elem = Xmldoc.getelementbyid ("add"); 362 string str = Elem. attributes["Value"].
Value 363  364  365  366 --------------------------------------------------------------------
367 <?xml version= "1.0" encoding= "Utf-8"?> 368 <configuration> 369 <appsettings> 370 <connectionstring>data SOURCE=YF; User id=ctm_dbo;password=123</connectionstring>  371 </appsettings> 372 </ Configuration> 373 -----------------------