C＃將節點附加到現有的xml文件

我正在使用XMLWriter創建聊天xml。該文件應通過將收到的消息追加到現有的聊天文件中進行更新。例如在下面的xml文件中，我想在msg_id = 5的節點之後附加一個新的消息節點。我的問題是我得到的代碼創建了一個新的XMl文件。請指教。C＃將節點附加到現有的xml文件

我的XML文件

<?xml version="1.0" encoding="utf-8"?> 
<client> 
    <name>client_name</name> 
    <url>client_name.myapp.com</url> 
    <ver>1</ver> 
    <conversation> 
     <sender_id>5</sender_id> 
     <fname>First</fname> 
     <mname>Middle</mname> 
     <lname>Last</lname> 
     <last_seen>l, d-M-y H:i:s T</last_seen> 
     <messages> 
      <message> 
       <msg_id>1</msg_id> 
       <recepient_id /> 
       <message>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</message> 
      </message> 
      <message> 
       <msg_id>2</msg_id> 
       <recepient_id /> 
       <message>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</message> 
      </message> 
      <message> 
       <msg_id>3</msg_id> 
       <recepient_id /> 
       <message>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</message> 
      </message> 
      <message> 
       <msg_id>4</msg_id> 
       <recepient_id /> 
       <message>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</message> 
      </message> 
      <message> 
       <msg_id>5</msg_id> 
       <recepient_id /> 
       <message>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</message> 
      </message> 
     </messages> 
    </conversation> 
</client>

我的代碼

chat = JsonConvert.DeserializeObject<Chat>(json_data); 

      for (int conversations_count = 0; conversations_count < chat.conversations.Count; conversations_count++) // Loop through List with for 
      { 
       var conversation = chat.conversations[conversations_count]; 
       var conversation_file_name = conversation.fname + " " + conversation.mname + " " + conversation.lname; 
       var messages = conversation.messages; 
       if (File.Exists(conversation_file_name)) 
       { 

       using (XmlWriter writer = XmlWriter.Create(conversation_file_name+".xml")) 
        { 
         writer.WriteStartDocument(); 
         writer.WriteStartElement("client"); 
         writer.WriteElementString("name", "client_name"); 
         writer.WriteElementString("url", "client_name.myapp.com"); 
         writer.WriteElementString("ver", "1.0"); 
         writer.WriteStartElement("conversation"); 
         writer.WriteElementString("sender_id", conversation.sender_id.ToString()); 
         writer.WriteElementString("fname", conversation.fname.ToString()); 
         writer.WriteElementString("mname", conversation.mname.ToString()); 
         writer.WriteElementString("lname", conversation.lname.ToString()); 
         writer.WriteElementString("last_seen", conversation.last_seen.ToString()); 
         writer.WriteStartElement("messages"); 
         for (int messages_count = 0; messages_count < messages.Count; messages_count++) // Loop through List with for 
         { 
          writer.WriteStartElement("message"); 

          writer.WriteElementString("msg_id", messages[messages_count].msg_id.ToString());       
          writer.WriteElementString("recepient_id", messages[messages_count].recepient_id.ToString()); 
          writer.WriteElementString("message", messages[messages_count].message.ToString()); 

          writer.WriteEndElement(); 
         } 
         writer.WriteEndElement(); 
         writer.WriteEndElement(); 
         writer.WriteEndElement(); 
         writer.WriteEndDocument(); 
        } 

       }    
      }

來源

2014-09-13 sammyukavi

這答案對我有用http：// stack overflow.com/questions/20922835/appending-an-existing-xml-file-with-xmlwriter?rq=1 – 2014-09-13 11:31:37

您是否必須使用'XmlWriter'來執行此操作，或者您可以移動到更簡單的API，如'XDocument'或'XmlDocument '？你使用的是什麼.NET框架版本？ – har07 2014-09-13 12:40:14

我正在使用.Net 2.0 – sammyukavi 2014-09-13 13:48:13

我建議你使用起來更加輕鬆XML API，例如，使用XmlDocument：

var doc = new XmlDocument(); 
doc.Load(conversation_file_name); 
var messagesNode = doc.DocumentElement 
         .SelectSingleNode("/client/conversation/messages"); 
var lastMessageId = messagesNode.SelectSingleNode("./message[last()]/msg_id"); 
var id = lastMessageId != null ? int.Parse(lastMessageId.InnerText.Trim()) : 0; 

for (int messages_count = 0; messages_count < messages.Count; messages_count++) // Loop through List with for 
{ 
    //create nodes to be added to existing XML 
    var newMessage = doc.CreateElement("message"); 
    var newId = doc.CreateElement("msg_id"); 
    var newRecepient = doc.CreateElement("recepient_id"); 
    var newMessageContent = doc.CreateElement("message"); 

    //set new nodes content 
    newId.InnerText = messages[messages_count].msg_id.ToString(); 
    newRecepient.InnerText = messages[messages_count].recepient_id.ToString(); 
    newMessageContent.InnerText = messages[messages_count].message.ToString(); 

    //append each node to desired parent node 
    newMessage.AppendChild(newId); 
    newMessage.AppendChild(newRecepient); 
    newMessage.AppendChild(newMessageContent); 
    messagesNode.AppendChild(newMessage); 
} 

doc.Save(conversation_file_name);

來源

2014-09-13 22:26:32 har07

C＃將節點附加到現有的xml文件

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