LINQ to XML一些基本查询

最新推荐文章于 2025-08-03 16:22:45 发布

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最新推荐文章于 2025-08-03 16:22:45 发布

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原文链接：http://www.cnblogs.com/zwl12549/archive/2008/11/02/1324571.html

本文介绍如何使用 LINQ to XML 进行 XML 数据的查询、筛选、排序及转换等操作，并展示了如何修改 XML 树结构，包括添加、删除元素及属性。

Code

/**/////根据元素的名称进行筛选（有命名空间）

//XNamespace aw = "http://www.adventure-works.com";

//XElement po = XElement.Load("PurchaseOrderInNamespace.xml");

//IEnumerable<XElement> items =

// from el in po.Descendants(aw + "ProductName")

// select el;

//foreach (XElement prdName in items)

// Console.WriteLine(prdName.Name + ":" + (string)prdName);

/**/////链接轴方法

//XElement purchaseOrders = XElement.Load("PurchaseOrders.xml");

//IEnumerable<XElement> names =

// from el in purchaseOrders

// .Elements("PurchaseOrder")

// .Elements("Address")

// .Elements("Name")

// select el;

//foreach (XElement e in names)

// Console.WriteLine(e);

/**/////链接轴方法,有时，当可能存在或不存在间隔上级时，您希望在特定的元素深度，检索所有的元素

//XElement root = XElement.Load("Irregular.xml");

//IEnumerable<XElement> configParameters =

// root.Elements("Customer").Elements("Config").

// Elements("ConfigParameter");

//foreach (XElement cp in configParameters)

// Console.WriteLine(cp);

/**/////检索单个子元素

//XElement po = XElement.Load("PurchaseOrder.xml");

//XElement e = po.Element("DeliveryNotes");

//Console.WriteLine(e);

/**/////检索索性的集合

//XElement val = new XElement("Value",

// new XAttribute("ID", "1243"),

// new XAttribute("Type", "int"),

// new XAttribute("ConvertableTo", "double"),

// "100");

//IEnumerable<XAttribute> listOfAttributes =

// from att in val.Attributes()

// select att;

//foreach (XAttribute a in listOfAttributes)

// Console.WriteLine(a);

/**/////检索单个属性

//XElement cust = new XElement("PhoneNumbers",

// new XElement("Phone",

// new XAttribute("type", "home"),

// "555-555-5555"),

// new XElement("Phone",

// new XAttribute("type", "work"),

// "555-555-6666")

// );

//IEnumerable<XElement> elList =

// from el in cust.Descendants("Phone")

// select el;

//foreach (XElement el in elList)

// Console.WriteLine((string)el.Attribute("type"));

/**/////检索属性值

//XElement root = new XElement("Root",

// new XAttribute("Attr", "abcde")

// );

//Console.WriteLine(root);

//string str = (string)root.Attribute("Attr");

//Console.WriteLine(str);

#endregion

基本查询#region 基本查询

/**/////查找具有特定属性的元素

//XElement root = XElement.Load("PurchaseOrder.xml");

//IEnumerable<XElement> address =

// from el in root.Elements("Address")

// where (string)el.Attribute("Type") == "Billing"

// select el;

//foreach (XElement el in address)

// Console.WriteLine(el);

/**/////查找具有特定子元素的元素

//XElement root = XElement.Load("TestConfig.xml");

//IEnumerable<XElement> tests =

// from el in root.Elements("Test")

// where (string)el.Element("CommandLine") == "Examp2.EXE"

// select el;

//foreach (XElement el in tests)

// Console.WriteLine((string)el.Attribute("TestId"));

//查询 XDocument 与查询 XElement

// //Create a simple document and write it to a file

// File.WriteAllText("Test.xml", @"<Root>

// <Child1>1</Child1>

// <Child2>2</Child2>

// <Child3>3</Child3>

// </Root>");

//Console.WriteLine("Querying tree loaded with XElement.Load");

//Console.WriteLine("----");

//XElement doc = XElement.Load("Test.xml");

//IEnumerable<XElement> childList =

// from el in doc.Elements()

// select el;

//foreach (XElement e in childList)

// Console.WriteLine(e);

//Console.WriteLine("Querying tree loaded with XDocument.Load");

//Console.WriteLine("----");

//XDocument doc = XDocument.Load("Test.xml");

//IEnumerable<XElement> childList =

// from el in doc.Elements()

// select el;

//foreach (XElement e in childList)

// Console.WriteLine(e);

// //查找具有特定元素名称的子代

// XElement root = XElement.Parse(@"<root>

// <para>

// <r>

// <t>Some text </t>

// </r>

// <n>

// <r>

// <t>that is broken up into </t>

// </r>

// </n>

// <n>

// <r>

// <t>multiple segments.</t>

// </r>

// </n>

// </para>

// </root>");

// IEnumerable<string> textSegs =

// from seg in root.Descendants("t")

// select (string)seg;

// string str = textSegs.Aggregate(new StringBuilder(),

// (sb, i) => sb.Append(i),

// sp => sp.ToString()

// );

// Console.WriteLine(str);

// //使用 Descendants 方法查找单个后代

// XElement root = XElement.Parse(@"<Root>

// <Child1>

// <GrandChild1>GC1 Value</GrandChild1>

// </Child1>

// <Child2>

// <GrandChild2>GC2 Value</GrandChild2>

// </Child2>

// <Child3>

// <GrandChild3>GC3 Value</GrandChild3>

// </Child3>

// <Child4>

// <GrandChild4>GC4 Value</GrandChild4>

// </Child4>

// </Root>");

// string grandChild3 = (string)

// (from el in root.Descendants("GrandChild3")

// select el).First();

// Console.WriteLine(grandChild3);

/**/////编写使用复杂筛选的查询

//XElement root = XElement.Load("PurchaseOrders.xml");

//IEnumerable<XElement> purchaseOrders =

// from el in root.Elements("PurchaseOrder")

// where

// (from add in el.Elements("Address")

// where

// (string)add.Attribute("Type") == "Shipping" &&

// (string)add.Element("State") == "NY"

// select add)

// .Any()

// select el;

//foreach (XElement el in purchaseOrders)

// Console.WriteLine((string)el.Attribute("PurchaseOrderNumber"));

// //筛选可选元素

// XElement root = XElement.Parse(@"<Root>

// <Child1>

// <Text>Child One Text</Text>

// <Type Value=""Yes""/>

// </Child1>

// <Child2>

// <Text>Child Two Text</Text>

// <Type Value=""Yes""/>

// </Child2>

// <Child3>

// <Text>Child Three Text</Text>

// <Type Value=""No""/>

// </Child3>

// <Child4>

// <Text>Child Four Text</Text>

// <Type Value=""Yes""/>

// </Child4>

// <Child5>

// <Text>Child Five Text</Text>

// </Child5>

// </Root>");

// var cList =

// from typeElement in root.Elements().Elements("Type")

// where (string)typeElement.Attribute("Value") == "Yes"

// select (string)typeElement.Parent.Element("Text");

// foreach (string str in cList)

// Console.WriteLine(str);

/**/////对元素进行排序

//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);

/**/////对多个键上的元素进行排序

//XElement co = XElement.Load("CustomersOrders.xml");

//var sortedElements =

// from c in co.Element("Orders").Elements("Order")

// orderby (string)c.Element("ShipInfo").Element("ShipPostalCode"),

// (DateTime)c.Element("OrderDate")

// select new

// {

// CustomerID = (string)c.Element("CustomerID"),

// EmployeeID = (string)c.Element("EmployeeID"),

// ShipPostalCode = (string)c.Element("ShipInfo").Element("ShipPostalCode"),

// OrderDate = (DateTime)c.Element("OrderDate")

// };

//foreach (var r in sortedElements)

// Console.WriteLine("CustomerID:{0} EmployeeID:{1} ShipPostalCode:{2} OrderDate:{3:d}",

// r.CustomerID, r.EmployeeID, r.ShipPostalCode, r.OrderDate);

//计算中间值

//XElement root = XElement.Load("Data.xml");

//IEnumerable<decimal> extensions =

// from el in root.Elements("Data")

// let extension = (decimal)el.Element("Quantity") * (decimal)el.Element("Price")

// where extension >= 25

// orderby extension

// select extension;

//foreach (decimal ex in extensions)

// Console.WriteLine(ex);

// // 编写基于上下文查找元素的查询

// XElement doc = XElement.Parse(@"<Root>

//

// <ul>abc</ul>

// <Child>

//

// <notul/>

//

// <ul>def</ul>

//

// </Child>

// <Child>

//

// <notul/>

//

// <ul>abc</ul>

//

// </Child>

// </Root>");

// IEnumerable<XElement> items =

// from e in doc.Descendants("p")

// let z = e.ElementsAfterSelf().FirstOrDefault()

// where z != null && z.Name.LocalName == "ul"

// select e;

// foreach (XElement e in items)

// Console.WriteLine("id = {0}", (string)e.Attribute("id"));

//调试空查询结果集

// XElement root = XElement.Parse(

// @"<Root xmlns='http://www.adventure-works.com'>

// <Child>1</Child>

// <Child>2</Child>

// <Child>3</Child>

// <AnotherChild>4</AnotherChild>

// <AnotherChild>5</AnotherChild>

// <AnotherChild>6</AnotherChild>

// </Root>");

// IEnumerable<XElement> c1 =

// from el in root.Elements("Child")

// select el;

// Console.WriteLine("Result set follows:");

// foreach (XElement el in c1)

// Console.WriteLine((int)el);

// Console.WriteLine("End of result set");

// XElement root = XElement.Parse(

// @"<Root xmlns='http://www.adventure-works.com'>

// <Child>1</Child>

// <Child>2</Child>

// <Child>3</Child>

// <AnotherChild>4</AnotherChild>

// <AnotherChild>5</AnotherChild>

// <AnotherChild>6</AnotherChild>

// </Root>");

// XNamespace aw = "http://www.adventure-works.com";

// IEnumerable<XElement> c1 =

// from el in root.Elements(aw + "Child")

// select el;

// Console.WriteLine("Result set follows:");

// foreach (XElement el in c1)

// Console.WriteLine((int)el);

// Console.WriteLine("End of result set");

#endregion

投影和转换#region 投影和转换

//通过 LINQ to XML 使用字典

//Dictionary<string, string> dict = new Dictionary<string, string>();

//dict.Add("Child1", "Value1");

//dict.Add("Child2", "Value2");

//dict.Add("Child3", "Value3");

//dict.Add("Child4", "Value4");

//XElement root = new XElement("Root",

// from keyValue in dict

// select new XElement(keyValue.Key, keyValue.Value)

//);

//Console.WriteLine(root);

//XElement root = new XElement("Root",

// new XElement("Child1", "Value1"),

// new XElement("Child2", "Value2"),

// new XElement("Child3", "Value3"),

// new XElement("Child4", "Value4")

//);

//Dictionary<string, string> dict = new Dictionary<string, string>();

//foreach (XElement el in root.Elements())

// dict.Add(el.Name.LocalName, el.Value);

//foreach (string str in dict.Keys)

// Console.WriteLine("{0}:{1}", str, dict[str]);

/**/////转换 XML 树的形状

//XElement co = XElement.Load("CustomersOrders.xml");

//XElement newCustOrd =

// new XElement("Root",

// from cust in co.Element("Customers").Elements("Customer")

// select new XElement("Customer",

// cust.Attributes(),

// cust.Elements(),

// new XElement("Orders",

// from ord in co.Element("Orders").Elements("Order")

// where (string)ord.Element("CustomerID") == (string)cust.Attribute("CustomerID")

// select new XElement("Order",

// ord.Attributes(),

// ord.Element("EmployeeID"),

// ord.Element("OrderDate"),

// ord.Element("RequiredDate"),

// ord.Element("ShipInfo")

// )

// );

//Console.WriteLine(newCustOrd);

/**/////投影匿名类型

//XElement custOrd = XElement.Load("CustomersOrders.xml");

//var custList =

// from el in custOrd.Element("Customers").Elements("Customer")

// select new

// {

// CustomerID = (string)el.Attribute("CustomerID"),

// CompanyName = (string)el.Element("CompanyName"),

// ContactName = (string)el.Element("ContactName")

// };

//foreach (var cust in custList)

// Console.WriteLine("{0}:{1}:{2}", cust.CustomerID, cust.CompanyName, cust.ContactName);

/**/////从 XML 生成文本文件

//XElement custOrd = XElement.Load("CustomersOrders.xml");

//string csv =

// (from el in custOrd.Element("Customers").Elements("Customer")

// select

// String.Format("{0},{1},{2},{3},{4},{5},{6},{7},{8},{9}{10}",

// (string)el.Attribute("CustomerID"),

// (string)el.Element("CompanyName"),

// (string)el.Element("ContactName"),

// (string)el.Element("ContactTitle"),

// (string)el.Element("Phone"),

// (string)el.Element("FullAddress").Element("Address"),

// (string)el.Element("FullAddress").Element("City"),

// (string)el.Element("FullAddress").Element("Region"),

// (string)el.Element("FullAddress").Element("PostalCode"),

// (string)el.Element("FullAddress").Element("Country"),

// Environment.NewLine

// )

// .Aggregate(

// new StringBuilder(),

// (sb, s) => sb.Append(s),

// sb => sb.ToString()

// );

//Console.WriteLine(csv);

// //从 CSV 文件生成 XML

// // Create the text file.

// string csvString = @"GREAL,Great Lakes Food Market,Howard Snyder,Marketing Manager,(503) 555-7555,2732 Baker Blvd.,Eugene,OR,97403,USA

// HUNGC,Hungry Coyote Import Store,Yoshi Latimer,Sales Representative,(503) 555-6874,City Center Plaza 516 Main St.,Elgin,OR,97827,USA

// LAZYK,Lazy K Kountry Store,John Steel,Marketing Manager,(509) 555-7969,12 Orchestra Terrace,Walla Walla,WA,99362,USA

// LETSS,Let's Stop N Shop,Jaime Yorres,Owner,(415) 555-5938,87 Polk St. Suite 5,San Francisco,CA,94117,USA";

// File.WriteAllText("cust.csv", csvString);

// // Read into an array of strings.

// string[] source = File.ReadAllLines("cust.csv");

// XElement cust = new XElement("Root",

// from str in source

// let fields = str.Split(',')

// select new XElement("Customer",

// new XAttribute("CustomerID", fields[0]),

// new XElement("CompanyName", fields[1]),

// new XElement("ContactName", fields[2]),

// new XElement("ContactTitle", fields[3]),

// new XElement("Phone", fields[4]),

// new XElement("FullAddress",

// new XElement("Address", fields[5]),

// new XElement("City", fields[6]),

// new XElement("Region", fields[7]),

// new XElement("PostalCode", fields[8]),

// new XElement("Country", fields[9])

// )

// );

// Console.WriteLine(cust);

#endregion

高级查询技术#region 高级查询技术

/**/////联接两个集合

//XmlSchemaSet schemas = new XmlSchemaSet();

//schemas.Add("", "CustomersOrders.xsd");

//Console.Write("Attempting to validate, ");

//XDocument custOrdDoc = XDocument.Load("CustomersOrders.xml");

//bool errors = false;

//custOrdDoc.Validate(schemas, (o, e) =>

//{

// Console.WriteLine("{0}", e.Message);

// errors = true;

//});

//Console.WriteLine("custOrdDoc {0}", errors ? "did not validate" : "validated");

//if (!errors)

//{

// // Join customers and orders, and create a new XML document with

// // a different shape.

// // The new document contains orders only for customers with a

// // CustomerID > 'K'

// XElement custOrd = custOrdDoc.Element("Root");

// XElement newCustOrd = new XElement("Root",

// from c in custOrd.Element("Customers").Elements("Customer")

// join o in custOrd.Element("Orders").Elements("Order")

// on (string)c.Attribute("CustomerID") equals

// (string)o.Element("CustomerID")

// where ((string)c.Attribute("CustomerID")).CompareTo("K") > 0

// select new XElement("Order",

// new XElement("CustomerID", (string)c.Attribute("CustomerID")),

// new XElement("CompanyName", (string)c.Element("CompanyName")),

// new XElement("ContactName", (string)c.Element("ContactName")),

// new XElement("EmployeeID", (string)o.Element("EmployeeID")),

// new XElement("OrderDate", (DateTime)o.Element("OrderDate"))

// )

// );

// Console.WriteLine(newCustOrd);

//}

/**/////使用分组创建层次结构

//XElement doc = XElement.Load("Data.xml");

//var newData =

// new XElement("Root",

// from data in doc.Elements("Data")

// group data by (string)data.Element("Category") into groupedData

// select new XElement("Group",

// new XAttribute("ID", groupedData.Key),

// from g in groupedData

// select new XElement("Data",

// g.Element("Quantity"),

// g.Element("Price")

// )

// );

//Console.WriteLine(newData);

/**/////执行文本到 XML 的流式转换

//StreamReader sr = new StreamReader("People.txt");

//XStreamingElement xmlTree = new XStreamingElement("Root",

// from line in sr.Lines()

// let items = line.Split(',')

// where !line.StartsWith("#")

// select new XElement("Person",

// new XAttribute("ID", items[0]),

// new XElement("First", items[1]),

// new XElement("Last", items[2]),

// new XElement("Occupation", items[3])

// )

//);

//Console.WriteLine(xmlTree);

//sr.Close();

/**/////使用 XPath 查询 LINQ to XML

//XElement root = new XElement("Root",

// new XElement("Child1", 1),

// new XElement("Child1", 2),

// new XElement("Child1", 3),

// new XElement("Child2", 4),

// new XElement("Child2", 5),

// new XElement("Child2", 6)

//);

//IEnumerable<XElement> list = root.XPathSelectElements("./Child2");

//foreach (XElement el in list)

// Console.WriteLine(el);

#endregion

修改XML树#region 修改XML树

/**/////将属性转换为元素

//XElement root = XElement.Load("Data1.xml");

//foreach (XAttribute att in root.Attributes())

//{

// root.Add(new XElement(att.Name, (string)att));

//}

//root.Attributes().Remove();

//Console.WriteLine(root);

/**/////函数构造

//XElement root = XElement.Load("Data1.xml");

//XElement newTree = new XElement("Root",

// root.Element("Child1"),

// from att in root.Attributes()

// select new XElement(att.Name, (string)att)

//);

//Console.WriteLine(newTree);

/**/////向树中添加元素

//XElement srcTree = new XElement("Root",

// new XElement("Element1", 1),

// new XElement("Element2", 2),

// new XElement("Element3", 3),

// new XElement("Element4", 4),

// new XElement("Element5", 5)

//);

//XElement xmlTree = new XElement("Root",

// new XElement("Child1", 1),

// new XElement("Child2", 2),

// new XElement("Child3", 3),

// new XElement("Child4", 4),

// new XElement("Child5", 5)

//);

//xmlTree.Add(new XElement("NewChild", "new content"));

//xmlTree.Add(

// from el in srcTree.Elements()

// where (int)el > 3

// select el

//);

/**///// Even though Child9 does not exist in srcTree, the following statement will not

//// throw an exception, and nothing will be added to xmlTree.

//xmlTree.Add(srcTree.Element("Child9"));

//Console.WriteLine(xmlTree);

//移除元素

// XElement root = XElement.Parse(@"<Root>

// <Child1>

// <GrandChild1/>

// <GrandChild2/>

// <GrandChild3/>

// </Child1>

// <Child2>

// <GrandChild4/>

// <GrandChild5/>

// <GrandChild6/>

// </Child2>

// <Child3>

// <GrandChild7/>

// <GrandChild8/>

// <GrandChild9/>

// </Child3>

// </Root>");

// root.Element("Child1").Element("GrandChild1").Remove();

// root.Element("Child2").Elements().ToList().Remove();

// root.Element("Child3").Elements().Remove();

// Console.WriteLine(root);

/**/////维护名称/值对

//// Create an element with no content.

//XElement root = new XElement("Root");

/**///// Add a number of name/value pairs as attributes.

//root.SetAttributeValue("Top", 22);

//root.SetAttributeValue("Left", 20);

//root.SetAttributeValue("Bottom", 122);

//root.SetAttributeValue("Right", 300);

//root.SetAttributeValue("DefaultColor", "Color.Red");

//Console.WriteLine(root);

/**///// Replace the value of Top.

//root.SetAttributeValue("Top", 10);

//Console.WriteLine(root);

/**///// Remove DefaultColor.

//root.SetAttributeValue("DefaultColor", null);

//Console.WriteLine(root);

/**/////元素名称/值对

//// Create an element with no content.

//XElement root = new XElement("Root");

/**///// Add a number of name/value pairs as elements.

//root.SetElementValue("Top", 22);

//root.SetElementValue("Left", 20);

//root.SetElementValue("Bottom", 122);

//root.SetElementValue("Right", 300);

//root.SetElementValue("DefaultColor", "Color.Red");

//Console.WriteLine(root);

//Console.WriteLine("----");

/**///// Replace the value of Top.

//root.SetElementValue("Top", 10);

//Console.WriteLine(root);

//Console.WriteLine("----");

/**///// Remove DefaultColor.

//root.SetElementValue("DefaultColor", null);

//Console.WriteLine(root);

#endregion

转载于:https://www.cnblogs.com/zwl12549/archive/2008/11/02/1324571.html