使用XmlWriter附加现有XML文件

Question

我使用以下代码创建XML文件：XmlWriterSettings xmlWriterSettings = new XmlWriterSettings();xmlWriterSettings.Indent = true;xmlWriterSettings.NewLineOnAttributes = true;using (XmlWriter xmlWriter = XmlWriter.Create("Test.xml", xmlWriterSettings)){   xmlWriter.WriteStartDocument();   xmlWriter.WriteStartElement("School");   xmlWriter.WriteEndElement();   xmlWriter.WriteEndDocument();   xmlWriter.Close(); }我需要动态创建以下结构来插入节点：<?xml version="1.0" encoding="utf-8"?><School />   <Student>      <FirstName>David</FirstName>      <LastName>Smith</LastName>   </Student>   ...   <Teacher>      <FirstName>David</FirstName>      <LastName>Smith</LastName>   </Teacher>   ...</School>我该怎么做？应该从键盘上读取“ FirstName”和“ LastName”的值，并且可以随时输入这些值，当然在现有的情况下。

Answer 1

终于我成功了:)

if (!File.Exists("Test.xml"))

{

   XmlWriterSettings xmlWriterSettings = new XmlWriterSettings();

   xmlWriterSettings.Indent = true;

   xmlWriterSettings.NewLineOnAttributes = true;

   using (XmlWriter xmlWriter = XmlWriter.Create("Test.xml", xmlWriterSettings))

   {

      xmlWriter.WriteStartDocument();

      xmlWriter.WriteStartElement("School");

      xmlWriter.WriteStartElement("Student");

      xmlWriter.WriteElementString("FirstName", firstName);

      xmlWriter.WriteElementString("LastName", lastName);

      xmlWriter.WriteEndElement();

      xmlWriter.WriteEndElement();

      xmlWriter.WriteEndDocument();

      xmlWriter.Flush();

      xmlWriter.Close();

   }

}

else

{

   XDocument xDocument = XDocument.Load("Test.xml");

   XElement root= xDocument.Element("School");

   IEnumerable<XElement> rows = root.Descendants("Student");

   XElement firstRow= rows.First();

   firstRow.AddBeforeSelf(

      new XElement("Student",

      new XElement("FirstName", firstName),

      new XElement("LastName", lastName)));

   xDocument.Save("Test.xml");

}

Answer 2

让我给你一个建议。创建xml文件时，请给学生一个唯一的ID，如下所示：

// to store the id variable, if you create more than one student you can increase it

count = 0; 

xmlWriter.WriteStartElement("School");

xmlWriter.WriteAttributeString("ID",count.ToString());

xmlWriter.WriteEndElement();

然后，当您需要向该学生添加信息时，您可以获得ID，Firstname并且Lastname可以使用LINQ to XML编辑XML文件，如下所示：

int id = Convert.ToInt32(txtStudentId.Text);

XDocument xDoc = XDocument.Load("Test.xml");

XElement student = xDoc.Descendants("Student").Where(x => (string) x.Attribute("ID") == id).FirstOrDefault();

if (student != null)

{

   string firstName = txtFirstName.Text;

   string lastName = txtLastName.Text;

   XElement first = new XElement("FirstName", firstName);

   XElement last = new XElement("LastName", lastName);

   student.Add(first);

   student.Add(last);

   xDoc.Save("Test.xml");

}