Linq toXML-XMLドキュメントのノードを更新/変更します
2つの質問があります：
1.私はLinq to XMLを使って作業しましたが、Linqを介してXMLドキュメントを変更できるかどうか疑問に思っています。つまり、何かのようなものがありますか
XDocument xmlDoc = XDocument.Load("sample.xml");
update item in xmlDoc.Descendants("item")
where (int)item .Attribute("id") == id
...
2.を使用して、新しいXMLElementを作成および追加する方法をすでに知っています。
xmlDoc.Element("items").Add(new XElement(......);
しかし、どうすれば単一のエントリを削除できますか？
XMLサンプルデータ：
<items>
<item id="1" name="sample1" info="sample1 info" web="" />
<item id="2" name="sample2" info="sample2 info" web="" />
</itmes>
答えてくれてありがとう。すべてが正常に動作します。
私の質問との競争と同じように、以下のコードは単一のエントリを変更する方法を示しています。
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");
これはあなたが考えていることですか？
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();
}
答えはこのスレッドにあります...あなたはそれらを見つけるためにたくさんのソートをしなければならないので、私はあなたのためにそれらをコンパイルする仕事をしました：
- はい、要素を編集できます
- 要素の削除は簡単です：element.Remove（）; （その後、xDocumentを保存することを忘れないでください）
このスレッドを読んでいる場合は、要素を編集する方法を知りたいと思うでしょう。データをxmlに保存する方法は2つあります。例：
<tagName attributeName="some value">another value</tagName>
- タグの属性として
- タグの内容（読み取り値）として
属性の値を編集するために、knoxは彼自身の質問に答えました：
d.Descendants("record").Where(x => x.Attribute("id").Value == "2").Single().SetAttributeValue("info", "new sample info");
つまり、変更するXElementを取得し、element.SetAttributeValue（ "AttributeName"、 "属性の新しい値"）を呼び出します。
タグの値または内容を編集したい場合、Ajayはそれに答えました（彼のすべてのコードを掘り下げた場合）：
persondata.Element("City").Value = txtCity.Text;
または、言い換えると、目的のXElementを取得したら、.Valueを使用して割り当てます。
メモリ内の要素に対してこれらの変更のいずれかを実行した後、それらの変更をディスクに永続化する場合は、XDocumentで.Save（）を呼び出す必要があることに注意してください。
システムを使用する; System.Collections.Generic;を使用します。 System.Linqを使用する; System.Textを使用します。 System.Xml.Linqを使用します。 //System.Xmlを使用します;
名前空間XMLtoLinqApp {クラスプログラム{staticvoid 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（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-> 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