Linq to XML – 更新/更改XML文档的节点

我有两个问题：

1.我已经开始使用Linq来处理XML，我想知道是否可以通过Linq更改XML文档。 我的意思是，有什么喜欢的

XDocument xmlDoc = XDocument.Load("sample.xml"); update item in xmlDoc.Descendants("item") where (int)item .Attribute("id") == id ... 

2.我已经知道如何通过简单地使用创建和添加新的XMLElement

 xmlDoc.Element("items").Add(new XElement(......); 

但是如何删除单个条目？

XML示例数据：

Answer 1

谢谢您的回答。 一切正常。

就像我的问题的完整性一样，下面的代码显示了如何修改单个条目：

 string xml = @""; StringReader sr = new StringReader(xml); XDocument d = XDocument.Load(sr); d.Descendants("record").Where(x => x.Attribute("id").Value == "2").Single().SetAttributeValue("info", "new sample info"); 

Answer 2

这是你的想法吗？

 using System; using System.Linq; using System.Xml.Linq; static void Main(string[] args) { string xml = @""; StringReader sr = new StringReader(xml); XDocument d = XDocument.Load(sr); // the verbose way, if you will be removing many elements (though in // this case, we're only removing one) var list = from XElement e in d.Descendants("record") where e.Attribute("id").Value == "2" select e; // convert the list to an array so that we're not modifying the // collection that we're iterating over foreach (XElement e in list.ToArray()) { e.Remove(); } // the concise way, which only works if you're removing a single element // (and will blow up if the element isn't found) d.Descendants("record").Where(x => x.Attribute("id").Value == "3").Single().Remove(); XmlWriter xw = XmlWriter.Create(Console.Out); d.WriteTo(xw); xw.Flush(); Console.ReadLine(); } 

Answer 3

答案在这个post中…你只需要做很多排序就可以找到它们，所以我已经完成了为你拼凑它们的工作：

1. 是的，你可以编辑元素
2. 删除元素很简单：element.Remove（）; （记得在那之后保存xDocument）

现在，如果您正在阅读此主题，您可能想知道如何编辑元素。 数据存储在xml中有两种不同的方式，例如：

 another value 

1. 作为标签上的ATTRIBUTE
2. 作为标签的内容（读取值）

为了编辑属性的值，knox回答了他自己的问题：

 d.Descendants("record").Where(x => x.Attribute("id").Value == "2").Single().SetAttributeValue("info", "new sample info"); 

换句话说，获取要更改的XElement，并调用element.SetAttributeValue（“AttributeName”，“属性的新值”）

如果你想编辑标签的值或内容 ，那么Ajay会回答它（如果你仔细检查他的所有代码）：

 persondata.Element("City").Value = txtCity.Text; 

或者，换句话说，一旦你拥有了你想要的XElement，只需使用.Value并分配。

请记住，在对内存中的元素执行任何这些修改之后，如果要将这些更改保留到磁盘，则必须在XDocument上调用.Save（）。

Answer 4

使用系统; 使用System.Collections.Generic; 使用System.Linq; 使用System.Text; 使用System.Xml.Linq; //使用System.Xml;

namespace XMLtoLinqApp {class Program {static void Main（string [] args）{

  //XmlDocument doc = new XmlDocument(); //XmlElement newBook=doc.CreateElement("BookParticipant"); //newBook.SetAttribute("Author"); //Using Functional Construction to Create an XML Schema XElement xBookParticipant = new XElement("BookParticipant", new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")); Console.WriteLine(xBookParticipant.ToString()); //Creates the Same XML Tree as Listing 6-1 but with Far Less Code XElement xBookParticipants = new XElement("BookParticipants", new XElement("BookParticipant", new XAttribute("type", "Author"), new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")), new XElement("BookParticipant", new XAttribute("type", "Editor"), new XElement("FirstName", "Ewan"), new XElement("LastName", "Buckingham"))); Console.WriteLine(xBookParticipants.ToString()); //-- Disadvatages of XML document //System.Xml.XmlElement xmlBookParticipant = new System.Xml.XmlElement("BookParticipant"); XElement xeBookParticipant = new XElement("BookParticipant"); XDocument xDocument = new XDocument(new XElement("BookParticipants", new XElement("BookParticipant", new XAttribute("type", "Author"), new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")))); Console.WriteLine(xDocument.ToString()); //--Calling the ToString Method on an Element Produces the XML Tree XElement name = new XElement("Name", "Joe"); Console.WriteLine(name.ToString()); //--Console.WriteLine Implicitly Calling the ToString Method on an Element to Produce an XML Tree XElement name1 = new XElement("Person", new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")); Console.WriteLine(name1); //-- Casting an Element to Its Value's Data Type Outputs the Value Console.WriteLine(name); Console.WriteLine((string)name); //--Different Node Value Types Retrieved via Casting to the Node Value's Type XElement count = new XElement("Count", 12); Console.WriteLine(count); Console.WriteLine((int)count); XElement smoker = new XElement("Smoker", false); Console.WriteLine(smoker); Console.WriteLine((bool)smoker); XElement pi = new XElement("Pi", 3.1415926535); Console.WriteLine(pi); Console.WriteLine((double)pi); DeferredQryProblem(); GenerateXMlFromLinqQry(); WithoutReaching(); Ancestors(); AncestorsAndSelf(); SortSample(); FindElementwithSpecificChild(); } private static void DeferredQryProblem() { XDocument xDocument = new XDocument( new XElement("BookParticipants", new XElement("BookParticipant", new XAttribute("type", "Author"), new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")), new XElement("BookParticipant", new XAttribute("type", "Editor"), new XElement("FirstName", "Ewan"), new XElement("LastName", "Buckingham")))); IEnumerable elements = xDocument.Element("BookParticipants").Elements("BookParticipant"); foreach (XElement element in elements) { Console.WriteLine("Source element: {0} : value = {1}", element.Name, element.Value); } foreach (XElement element in elements) { Console.WriteLine("Removing {0} = {1} ...", element.Name, element.Value); element.Remove(); } Console.WriteLine(xDocument); foreach (XElement element in elements) { Console.WriteLine("Source element: {0} : value = {1}", element.Name, element.Value); } foreach (XElement element in elements.ToArray()) { Console.WriteLine("Removing {0} = {1} ...", element.Name, element.Value); element.Remove(); } Console.WriteLine(xDocument); } //-- Creating an Attribute and Adding It to Its Element private static void CreatingAttribute() { XElement xBookParticipant = new XElement("BookParticipant", new XAttribute("type", "Author")); Console.WriteLine(xBookParticipant); } //--Creating a Comment with Functional Construction private static void CreatingComment() { XElement xBookParticipant = new XElement("BookParticipant", new XComment("This person is retired.")); Console.WriteLine(xBookParticipant); } //--Creating a Declaration with Functional Construction private static void CreateXmlDeclaration() { XDocument xDocument = new XDocument(new XDeclaration("1.0", "UTF-8", "yes"), 

新的XElement（“BookParticipant”））; Console.WriteLine（的XDocument）; }

  private static void GenerateXMlFromLinqQry() { BookParticipant[] bookParticipants = new[] {new BookParticipant {FirstName = "Joe", LastName = "Rattz", ParticipantType = ParticipantTypes.Author}, new BookParticipant {FirstName = "Ewan", LastName = "Buckingham", ParticipantType = ParticipantTypes.Editor} }; XElement xBookParticipants = new XElement("BookParticipants", bookParticipants.Select(p => new XElement("BookParticipant", new XAttribute("type", p.ParticipantType), new XElement("FirstName", p.FirstName), new XElement("LastName", p.LastName)))); Console.WriteLine(xBookParticipants); } //-- Obtaining Elements Without Reaching private static void WithoutReaching() { XDocument xDocument = new XDocument(new XElement("BookParticipants", new XElement("BookParticipant", new XAttribute("type", "Author"), new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")), new XElement("BookParticipant", new XAttribute("type", "Editor"), new XElement("FirstName", "Ewan"), new XElement("LastName", "Buckingham")))); //-- Simple Descendants IEnumerable elements = xDocument.Descendants("BookParticipant"); foreach (XElement element in elements) { Console.WriteLine("Element: {0} : value = {1}", element.Name, element.Value); } //-- Descendants with Where Clause IEnumerable elements1 = xDocument.Descendants("BookParticipant") .Where(e => ((string)e.Element("FirstName")) == "Ewan"); foreach (XElement element1 in elements1) { Console.WriteLine("Element: {0} : value = {1}", element1.Name, element1.Value); } } //-- Ancestors Prototype private static void Ancestors() { XDocument xDocument = new XDocument(new XElement("BookParticipants", new XElement("BookParticipant", new XAttribute("type", "Author"), new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")), new XElement("BookParticipant", new XAttribute("type", "Editor"), new XElement("FirstName", "Ewan"), new XElement("LastName", "Buckingham")))); IEnumerable elements = xDocument.Element("BookParticipants").Descendants("FirstName"); // First, I will display the source elements. foreach (XElement element in elements) { Console.WriteLine("Source element: {0} : value = {1}", element.Name, element.Value); } // Now, I will display the ancestor elements for each source element. foreach (XElement element in elements.Ancestors()) { Console.WriteLine("Ancestor element: {0}", element.Name); } // Now, I will display the ancestor elements for each source element. foreach (XElement element in elements.Ancestors("BookParticipant")) { Console.WriteLine("Ancestor element: {0}", element.Name); } } //-- AncestorsAndSelf private static void AncestorsAndSelf() { XDocument xDocument = new XDocument( new XElement("BookParticipants", new XElement("BookParticipant", new XAttribute("type", "Author"), new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")), new XElement("BookParticipant", new XAttribute("type", "Editor"), new XElement("FirstName", "Ewan"), new XElement("LastName", "Buckingham")))); IEnumerable elements = xDocument.Element("BookParticipants").Descendants("FirstName"); // First, I will display the source elements. foreach (XElement element in elements) { Console.WriteLine("Source element: {0} : value = {1}", element.Name, element.Value); } // Now, I will display the ancestor elements for each source element. foreach (XElement element in elements.AncestorsAndSelf()) { Console.WriteLine("Ancestor element: {0}", element.Name); } // Now, I will display the ancestor elements for each source element. foreach (XElement element in elements.AncestorsAndSelf("BookParticipant")) { Console.WriteLine("Ancestor element: {0}", element.Name); } } //-- Sort Smaple private static void SortSample() { XElement root = XElement.Load("Data.xml"); IEnumerable prices = from el in root.Elements("Data") let price = (decimal)el.Element("Price") orderby price select price; foreach (decimal el in prices) Console.WriteLine(el); } //-- Find an Element with a Specific Child private static void FindElementwithSpecificChild() { XElement root = XElement.Load("data.xml"); IEnumerable tests = from el in root.Elements("Data") where (int)el.Element("Quantity") > 3 select el; foreach (XElement el in tests) Console.WriteLine((string)el.Attribute("TestId"); } } 

}

http://msdn.microsoft.com/en-us/library/bb387053.aspx

7.25 – > A 3 24.50 B 1 89.99 A 5 4.95 A 3 66.00 B 10 .99 A 15 29.00 B 8 6.99

Answer 5

 static void Main(string[] args) { //XmlDocument doc = new XmlDocument(); //XmlElement newBook=doc.CreateElement("BookParticipant"); //newBook.SetAttribute("Author"); //Using Functional Construction to Create an XML Schema XElement xBookParticipant = new XElement("BookParticipant", new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")); Console.WriteLine(xBookParticipant.ToString()); //Creates the Same XML Tree as Listing 6-1 but with Far Less Code XElement xBookParticipants = new XElement("BookParticipants", new XElement("BookParticipant", new XAttribute("type", "Author"), new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")), new XElement("BookParticipant", new XAttribute("type", "Editor"), new XElement("FirstName", "Ewan"), new XElement("LastName", "Buckingham"))); Console.WriteLine(xBookParticipants.ToString()); //-- Disadvatages of XML document //System.Xml.XmlElement xmlBookParticipant = new System.Xml.XmlElement("BookParticipant"); XElement xeBookParticipant = new XElement("BookParticipant"); XDocument xDocument = new XDocument(new XElement("BookParticipants", new XElement("BookParticipant", new XAttribute("type", "Author"), new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")))); Console.WriteLine(xDocument.ToString()); //--Calling the ToString Method on an Element Produces the XML Tree XElement name = new XElement("Name", "Joe"); Console.WriteLine(name.ToString()); //--Console.WriteLine Implicitly Calling the ToString Method on an Element to Produce an XML Tree XElement name1 = new XElement("Person", new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")); Console.WriteLine(name1); //-- Casting an Element to Its Value's Data Type Outputs the Value Console.WriteLine(name); Console.WriteLine((string)name); //--Different Node Value Types Retrieved via Casting to the Node Value's Type XElement count = new XElement("Count", 12); Console.WriteLine(count); Console.WriteLine((int)count); XElement smoker = new XElement("Smoker", false); Console.WriteLine(smoker); Console.WriteLine((bool)smoker); XElement pi = new XElement("Pi", 3.1415926535); Console.WriteLine(pi); Console.WriteLine((double)pi); DeferredQryProblem(); GenerateXMlFromLinqQry(); } private static void DeferredQryProblem() { XDocument xDocument = new XDocument( new XElement("BookParticipants", new XElement("BookParticipant", new XAttribute("type", "Author"), new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")), new XElement("BookParticipant", new XAttribute("type", "Editor"), new XElement("FirstName", "Ewan"), new XElement("LastName", "Buckingham")))); IEnumerable elements = xDocument.Element("BookParticipants").Elements("BookParticipant"); foreach (XElement element in elements) { Console.WriteLine("Source element: {0} : value = {1}", element.Name, element.Value); } foreach (XElement element in elements) { Console.WriteLine("Removing {0} = {1} ...", element.Name, element.Value); element.Remove(); } Console.WriteLine(xDocument); foreach (XElement element in elements) { Console.WriteLine("Source element: {0} : value = {1}", element.Name, element.Value); } foreach (XElement element in elements.ToArray()) { Console.WriteLine("Removing {0} = {1} ...", element.Name, element.Value); element.Remove(); } Console.WriteLine(xDocument); } //-- Creating an Attribute and Adding It to Its Element private static void CreatingAttribute() { XElement xBookParticipant = new XElement("BookParticipant", new XAttribute("type", "Author")); Console.WriteLine(xBookParticipant); } //--Creating a Comment with Functional Construction private static void CreatingComment() { XElement xBookParticipant = new XElement("BookParticipant", new XComment("This person is retired.")); Console.WriteLine(xBookParticipant); } //--Creating a Declaration with Functional Construction private static void CreateXmlDeclaration() { XDocument xDocument = new XDocument(new XDeclaration("1.0", "UTF-8", "yes"), new XElement("BookParticipant")); Console.WriteLine(xDocument); } private static void GenerateXMlFromLinqQry() { BookParticipant[] bookParticipants = new[] {new BookParticipant {FirstName = "Joe", LastName = "Rattz", ParticipantType = ParticipantTypes.Author}, new BookParticipant {FirstName = "Ewan", LastName = "Buckingham", ParticipantType = ParticipantTypes.Editor} }; XElement xBookParticipants = new XElement("BookParticipants", bookParticipants.Select(p => new XElement("BookParticipant", new XAttribute("type", p.ParticipantType), new XElement("FirstName", p.FirstName), new XElement("LastName", p.LastName)))); Console.WriteLine(xBookParticipants); } //-- Obtaining Elements Without Reaching private static void WithoutReaching() { XDocument xDocument = new XDocument(new XElement("BookParticipants", new XElement("BookParticipant", new XAttribute("type", "Author"), new XElement("FirstName", "Joe"), new XElement("LastName", "Rattz")), new XElement("BookParticipant", new XAttribute("type", "Editor"), new XElement("FirstName", "Ewan"), new XElement("LastName", "Buckingham")))); IEnumerable elements = xDocument.Descendants("BookParticipant"); foreach (XElement element in elements) { Console.WriteLine("Element: {0} : value = {1}", element.Name, element.Value); } IEnumerable elements1 = xDocument.Descendants("BookParticipant") .Where(e => ((string)e.Element("FirstName")) == "Ewan"); foreach (XElement element1 in elements1) { Console.WriteLine("Element: {0} : value = {1}", element1.Name, element1.Value); } } 

Answer 6

 using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Xml.Linq; namespace LinqToXmlTest { public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void ReadXml() { XDocument xdocument = XDocument.Load(Server.MapPath("People.xml")); var persons = from person in xdocument.Descendants("Person") select new { Name = person.Element("Name").Value, City = person.Element("City").Value, Age = person.Element("Age").Value }; litResults.Text = ""; foreach (var person in persons) { litResults.Text = litResults.Text + "Name: " + person.Name + "
"; litResults.Text = litResults.Text + "City: " + person.City + "
"; litResults.Text = litResults.Text + "Age: " + person.Age + "

"; } if (litResults.Text == "") litResults.Text = "No Results..."; } protected void butAdd_Click(object sender, EventArgs e) { try { if (txtName.Text == "" || txtCity.Text == "" || txtAge.Text == "") { lblStatus.ForeColor = System.Drawing.Color.Red; lblStatus.Text = "Please Complete the form"; } else { XDocument xdocumnet = XDocument.Load(Server.MapPath("People.xml")); xdocumnet.Element("Persons").Add(new XElement("Person", new XElement("Name", txtName.Text), new XElement("City", txtCity.Text), new XElement("Age", txtAge.Text))); xdocumnet.Save(Server.MapPath("People.xml")); lblStatus.ForeColor = System.Drawing.Color.Green; lblStatus.Text = "Data Successfully loaded to xml file"; txtName.Text = ""; txtCity.Text = ""; txtAge.Text = ""; ReadXml(); } } catch { lblStatus.ForeColor = System.Drawing.Color.Red; lblStatus.Text = "Sorry unable to precess request.Please try again"; } } protected void butRead_Click(object sender, EventArgs e) { ReadXml(); lblStatus.Text = ""; } protected void btnUpdate_Click(object sender, EventArgs e) { try { if (txtName.Text == "" || txtCity.Text == "" || txtAge.Text == "") { lblStatus.ForeColor = System.Drawing.Color.Red; lblStatus.Text = "Please enter all details in the form"; } else { XDocument xdocument = XDocument.Load(Server.MapPath("People.xml")); var persondata = (from person in xdocument.Descendants("Person") where person.Element("Name").Value.Equals(txtName.Text) select person).Single(); persondata.Element("City").Value = txtCity.Text; persondata.Element("Age").Value = txtAge.Text; xdocument.Save(Server.MapPath("People.xml")); lblStatus.ForeColor = System.Drawing.Color.Green; lblStatus.Text = "The data updated successfully"; ReadXml(); } } catch(Exception ex) { lblStatus.ForeColor = System.Drawing.Color.Red; lblStatus.Text = ex.Message; } } protected void btnDelete_Click(object sender, EventArgs e) { try { if (txtName.Text == "") { lblStatus.ForeColor = System.Drawing.Color.Red; lblStatus.Text = "Please enter the name of the person to delete..."; } else { XDocument xdocument = XDocument.Load(Server.MapPath("People.xml")); var persondata = (from person in xdocument.Descendants("Person") where person.Element("Name").Value.Equals(txtName.Text) select person).Single(); persondata.Remove(); xdocument.Save(Server.MapPath("People.xml")); lblStatus.ForeColor = System.Drawing.Color.Green; lblStatus.Text = "The data deleted successfully..."; txtName.Text = ""; txtCity.Text = ""; txtAge.Text = ""; ReadXml(); } } catch (Exception ex) { lblStatus.ForeColor = System.Drawing.Color.Red; lblStatus.Text = ex.Message; } } } }