C# 对xml数据的增删改差学习代码

<?xml version="1.0" standalone="yes"?> <person> <student> <id_no>9096036</id_no> <name>蔡文龙</name> <tel>04-32345671</tel> <mail>lung67@giga.net.tw</mail> </student> <student> <id_no>9096001</id_no> <name>许百宏</name> <tel>04-12345671</tel> <mail>em@ms37.hient.net</mail> </student> <student> <id_no>9096002</id_no> <name>林宜美</name> <tel>04-78955671</tel> <mail>em@ms37.yam.net</mail> </student> <student> <id_no>9096003</id_no> <name>赖玲英</name> <tel>049-6345671</tel> <mail>pc@ms56.hient.net</mail> </student> <student> <id_no>9096004</id_no> <name>丁胜勇</name> <tel>02-12344471</tel> <mail>em@ms37.hient.seed.tw</mail> </student> <student> <id_no>9096005</id_no> <name>刘晓珍</name> <tel>049-1345671</tel> <mail>yy@ms45.hient.net</mail> </student> <student> <id_no>9096006</id_no> <name>李逢源</name> <tel>06-11235671</tel> <mail>et@ms37.yam.net</mail> </student> <student> <id_no>9096007</id_no> <name>卓水信</name> <tel>02-17896671</tel> <mail>em@ms37.pchome.net</mail> </student> <student> <id_no>9096008</id_no> <name>谢沂臻</name> <tel>049-1234571</tel> <mail>em@ms56.pchome.net</mail> </student> <student> <id_no>9096009</id_no> <name>徐志宏</name> <tel>04-15465671</tel> <mail>pp@ms69.hient.net</mail> </student> <student> <id_no>9096010</id_no> <name>吴广信</name> <tel>04-12349999</tel> <mail>em@ms37.yahoo.net</mail> </student> <student> <id_no>9096011</id_no> <name>王富民</name> <tel>049-1478523</tel> <mail>em@ms69.hient.net</mail> </student> <student> <id_no>9096012</id_no> <name>蔡佳宣</name> <tel>04-78965671</tel> <mail>yy@ms69.pchome.net</mail> </student> <student> <id_no>9096013</id_no> <name>陈姿伶</name> <tel>04-65475671</tel> <mail>em@ms69.hient.net.tw</mail> </student> <student> <id_no>9096014</id_no> <name>林宜慧</name> <tel>06-2345671</tel> <mail>em@ms11.hient.net</mail> </student> <student> <id_no>9096015</id_no> <name>黄其政</name> <tel>04-545555671</tel> <mail>em@ms69.hient.net</mail> </student> <student> <id_no>9096016</id_no> <name>周小旬</name> <tel>04－1234567</tel> <mail>anlta@aaa.com.tw</mail> </student> </person>