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，有什么像
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
来创建和添加新的XMLElementxmlDoc.Element("items").Add(new XElement(......);
但如何删除单个条目？
XML示例数据：
<items>
<item id="1" name="sample1" info="sample1 info" web="" />
<item id="2" name="sample2" info="sample2 info" web="" />
</itmes>
答案 0 :(得分：16)
谢谢你的回答。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 = @"<data><record id='1' info='sample Info'/><record id='2' info='sample Info'/><record id='3' info='sample Info'/></data>";
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");
答案 1 :(得分：7)
这是你的想法吗？
using System;
using System.Linq;
using System.Xml.Linq;
static void Main(string[] args)
{
string xml = @"<data><record id='1'/><record id='2'/><record id='3'/></data>";
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();
}
答案 2 :(得分：1)
答案在这个帖子中......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：
现在，如果您正在阅读此主题，您可能想知道如何编辑元素。数据以两种不同的方式存储在xml中，例如：
<tagName attributeName="some value">another value</tagName>
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（如果你仔细查看他的所有代码）：
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后，如果要将这些更改保存到磁盘，则必须在XDocument上调用.Save（）。
答案 3 :(得分：0)
使用System; 使用System.Collections.Generic; 使用System.Linq; 使用System.Text; 使用System.Xml.Linq; //使用System.Xml;
命名空间XMLtoLinqApp { 课程 { 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<XElement> 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（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<XElement> elements = xDocument.Descendants("BookParticipant");
foreach (XElement element in elements)
{
Console.WriteLine("Element: {0} : value = {1}",
element.Name, element.Value);
}
//-- Descendants with Where Clause
IEnumerable<XElement> 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<XElement> 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<XElement> 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<decimal> 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<XElement> 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 - ＆GT; 一个 3 24.50 乙 1 89.99 一个 五 4.95 一个 3 66.00 乙 10 0.99 一个 15 29.00 乙 8 6.99
答案 4 :(得分：-1)
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<XElement> 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<XElement> elements = xDocument.Descendants("BookParticipant");
foreach (XElement element in elements)
{
Console.WriteLine("Element: {0} : value = {1}",
element.Name, element.Value);
}
IEnumerable<XElement> 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);
}
}
答案 5 :(得分：-2)
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 + "<br/>";
litResults.Text = litResults.Text + "City: " + person.City + "<br/>";
litResults.Text = litResults.Text + "Age: " + person.Age + "<br/><br/>";
}
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;
}
}
}
}