LINQ XML的基本操作

来源：互联网发布：linux openoffice日志编辑：程序博客网时间：2024/06/06 17:36

转自： http://blog.csdn.net/chinajiyong/article/details/7485019

这几天想写点基础的博客内容，正好最近在用XML，就写了一点XML的基本操作。

通过函数的形式表现出来。

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/*
-------------------------------------
Context：LINQ TO XML
-------------------------------------
Author：Chinajiyong
-------------------------------------
DateTime：2012-04-21
-------------------------------------
通过函数的形式表现出来
-------------------------------------
*/

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/// <summary>
/// 1、创建BookStore.xml的XML文件，由函数CreateXmlFile()完成
/// </summary>

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/// <param name="xmlpath">XML文件的路径</param>
private static void CreateXmlFile(string xmlpath)
{
XDocument doc = new XDocument( ///创建XDocument类的实例
new XDeclaration("1.0", "utf-8", "yes"),///XML的声明，包括版本，编码，xml文件是否独立
new XElement("Books", ///添加根节点
new XElement("Book", ///添加一个节点
new XAttribute("BookID", "001"),///添加属性BookID
new XElement("BookNo", "0001"), ///添加元素BookNo
new XElement("BookName", "Book 0001"),///添加元素BookName
new XElement("BookPrice", "40"),///添加元素BookPrice
new XElement("BookRemark", "This is a book 0001")///添加元素BookRemark
)
)
);
///保存XML文件到指定地址
doc.Save(xmlpath);
Console.WriteLine(doc);
}

调用函数CreateXmlFile(string xmlpath)

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static void Main(string[] args)
{
///创建一个名为BookStore.xml的xml文件
Program.CreateXmlFile(@"C:\BookStore.xml");
}

运行结果：

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/// <summary>
/// 2、添加元素
/// </summary>
/// <param name="xmlpath">XML文件的路径</param>
private static void AddXmlElement(string xmlpath)
{
///导入XML文件
XElement xe = XElement.Load(xmlpath);
///创建一个新节点
XElement book1 = new XElement("Book",
new XAttribute("BookID", "002"),
new XElement("BookNo", "0002"),
new XElement("BookName", "Book 0002"),
new XElement("BookPrice", "50"),
new XElement("BookRemark", "This is a book 0002")
);
///添加节点到XML文件中，并保存
xe.Add(book1);
///创建一个新节点
XElement book2 = new XElement("Book",
new XAttribute("BookID", "003"),
new XElement("BookNo", "0003"),
new XElement("BookName", "Book 0003"),
new XElement("BookPrice", "30"),
new XElement("BookRemark", "This is a book 0003")
);
///添加节点到XML文件中，并保存
xe.Add(book2);
///创建一个新节点
XElement book3 = new XElement("Book",
new XAttribute("BookID", "004"),
new XElement("BookNo", "0004"),
new XElement("BookName", "Book 0004"),
new XElement("BookPrice", "60"),
new XElement("BookRemark", "This is a book 0004")
);
///添加节点到XML文件中
xe.Add(book3);
///保存到XML文件中
xe.Save(xmlpath);
Console.WriteLine(xe);
}

调用函数AddXmlElement(string xmlpath)

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///添加XML元素
Program.AddXmlElement(@"C:\BookStore.xml");

运行结果：

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/// <summary>
/// 3、修改XML文件的元素
/// </summary>
/// <param name="xmlpath">XML文件的路径</param>
/// <param name="strElement">指定的修改元素</param>
private static void ModifyXmlElement(string xmlpath, string strElement)
{
XElement xe = XElement.Load(xmlpath);
///查询修改的元素
IEnumerable<XElement> element = from e in xe.Elements("Book")
where e.Attribute("BookID").Value == strElement
select e;
///修改元素
if (element.Count() > 0)
{
XElement firstelement = element.First();
///设置新的属性
firstelement.SetAttributeValue("BookID", "new004");
///替换成新的节点
firstelement.ReplaceNodes(
new XElement("BookNo", "new0004"),
new XElement("BookName", "Book new0004"),
new XElement("BookPrice", "45"),
new XElement("BookRemark", "This is a book new0004")
);
}
xe.Save(xmlpath);
Console.WriteLine(xe);
}

调用函数ModifyXmlElement(string xmlpath, string strElement)

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///修改XML文件的元素
Program.ModifyXmlElement(@"C:\BookStore.xml", "004");

运行结果：

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/// <summary>
/// 4、删除XML文件的元素
/// </summary>
/// <param name="xmlpath">XML文件的路径</param>
/// <param name="strElement">指定删除元素</param>
private static void DeleteXmlElement(string xmlpath, string strElement)
{
XElement xe = XElement.Load(xmlpath);
///查询修改的元素
IEnumerable<XElement> element = from e in xe.Elements("Book")
where e.Attribute("BookID").Value == strElement
select e;
///修改元素
if (element.Count() > 0)
{
XElement firstelement = element.First();
///删除此元素的所有节点和属性
firstelement.RemoveAll();
///删除此元素的属性
//firstelement.RemoveAttributes();
///删除此元素的子节点
//firstelement.RemoveNodes();
}
xe.Save(xmlpath);
Console.WriteLine(xe);
}

调用函数 DeleteXmlElement(string xmlpath, string strElement)

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///删除XML元素
Program.DeleteXmlElement(@"C:\BookStore.xml","new004");

运行结果：

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/// <summary>
/// 5、将XML文件中的属性更换成元素
/// </summary>
/// <param name="xmlpath">XML文件的路径</param>
/// <param name="strAttribute">指定要更换的属性</param>
private static void ConvertAttributeToElement(string xmlpath, string strAttribute)
{
XElement xe = XElement.Load(xmlpath);
///查询更换的元素
IEnumerable<XElement> element = from e in xe.Elements("Book")
where e.Attribute("BookID").Value == strAttribute
select e;
///更换为元素
if (element.Count() > 0)
{
XElement firstelement = element.First();
//获取第一个属性
XAttribute attr = firstelement.FirstAttribute;
//XAttribute attr = firstelement.Attribute("BookID");
///将属性转换成元素
firstelement.AddFirst(
new XElement(attr.Name, attr.Value)//添加BookID元素
);
///删除属性
firstelement.RemoveAttributes();
}
xe.Save(xmlpath);
Console.WriteLine(xe);
}

调用函数：ConvertAttributeToElement(string xmlpath, string strAttribute)

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///删除XML元素
//Program.DeleteXmlElement(@"C:\BookStore.xml","new004");//注释这一样
///将文件中的属性更换成元素
Program.ConvertAttributeToElement(@"C:\BookStore.xml","new004");

运行结果：

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/// <summary>
/// 6、查询根元素
/// </summary>
/// <param name="xmlpath">XML文件的路径</param>
private static void QueryRootElement(string xmlpath)
{
XDocument doc = XDocument.Load(xmlpath);
Console.WriteLine(doc.Root.Name);
//IEnumerable<XElement> RootElement = from root in doc.Elements("Books")
// select root;
/////输出根元素
//foreach (XElement xe in RootElement)
//{
// Console.WriteLine(xe.Name);
//}
}

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调用函数：QueryRootElement(string xmlpath)

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<pre name="code" class="csharp"> /// 查询根元素
Program.QueryRootElement(@"C:\BookStore.xml");</pre>运行结果：
<pre></pre>
<pre name="code" class="csharp" style="background-color: rgb(255, 255, 255); ">Books</pre><pre name="code" class="csharp"> /// <summary>
/// 7、查询指定名称的元素
/// </summary>
/// <param name="xmlpath">XML文件的路径</param>
/// <param name="strName">查询元素名称</param>
private static void QueryElementByName(string xmlpath, string strName)
{
XElement xe = XElement.Load(xmlpath);
///查询元素
var elements = xe.Elements("Book")
.Where(e => (string)e.Element("BookName") == strName)
.OrderBy(e => e.Element("BookName"))
.ToList();
elements.ForEach(e => Console.WriteLine(e));
}</pre>调用函数：QueryElementByName(string xmlpath, string strName)
<pre name="code" class="csharp"> ///查询指定名称的元素
Program.QueryElementByName(@"C:\BookStore.xml", "Book 0003");</pre>运行结果：
<img src="http://my.csdn.net/uploads/201204/21/1335011713_3231.png" alt="">
<pre name="code" class="csharp"> /// <summary>
/// 8、查询指定属性的元素
/// </summary>
/// <param name="xmlpath">XML文件的路径</param>
/// <param name="strName">指定的属性</param>
private static void QueryElementByAttribute(string xmlpath, string strAttribute)
{
XElement xe = XElement.Load(xmlpath);
///查询元素
var eAttribute = xe.Elements("Book")
.Where(e => (string)e.Attribute("BookID") == strAttribute)
.OrderBy(e => e.Element("BookID"))
.ToList();
eAttribute.ForEach(e => Console.WriteLine(e));
}</pre>调用函数：QueryElementByAttribute(string xmlpath, string strAttribute)
<pre name="code" class="csharp"> ///查询指定属性的元素
Program.QueryElementByAttribute(@"C:\BookStore.xml", "003");</pre>运行结果：
<img src="http://my.csdn.net/uploads/201204/21/1335011840_7341.png" alt="">
<pre name="code" class="csharp"> /// <summary>
/// 9、查询指定元素的子元素
/// </summary>
/// <param name="xmlpath">XML文件的路径</param>
/// <param name="strSubElement">指定元素</param>
private static void QuerySubElement(string xmlpath, string strSubElement)
{
XElement xe = XElement.Load(xmlpath);
var elements = xe.Elements("Book")
.Descendants("BookRemark")
.ToList();
foreach (var e in elements)
{
Console.WriteLine(e.Name.LocalName + "\t" + e.Value);
}
}</pre>调用函数：QuerySubElement(string xmlpath, string strSubElement)
<pre name="code" class="csharp"> ///查询指定元素的子元素
Program.QuerySubElement(@"C:\BookStore.xml", "BookRemark");</pre>运行结果：
<img src="http://my.csdn.net/uploads/201204/21/1335011970_6889.png" alt="">
<pre name="code" class="csharp"> /// <summary>
/// 10、查询元素并排序
/// </summary>
/// <param name="xmlpath">XML文件的路径</param>
private static void QueryElementByOrder(string xmlpath)
{
XElement xe = XElement.Load(xmlpath);
var elements = xe.Elements("Book")
.Where(e => Convert.ToInt32(e.Attribute("BookID").Value.Substring(e.Attribute("BookID").Value.Length - 1, 1)) > 1)
.OrderByDescending(e => (string)e.Element("BookName"))
.ToList();
elements.ForEach(e => Console.WriteLine(e.Element("BookName").Value));
}</pre>调用函数：QueryElementByOrder(string xmlpath)
<pre name="code" class="csharp"> /// 查询元素并排序
Program.QueryElementByOrder(@"C:\BookStore.xml");</pre>运行结果：
<img src="http://my.csdn.net/uploads/201204/21/1335012340_2136.png" alt="">
<pre name="code" class="csharp"> /// <summary>
/// 11、查询元素并计算Price平均值
/// </summary>
/// <param name="xmlpath">XML文件的路径</param>
private static void QueryElementByCoeompute(string xmlpath)
{
XElement xe = XElement.Load(xmlpath);
var elements = xe.Elements("Book")
.Where(e => Convert.ToInt32(e.Attribute("BookID").Value.Substring(e.Attribute("BookID").Value.Length - 1, 1)) > 1)
.OrderByDescending(e => (string)e.Element("BookName"))
.ToList();
Console.WriteLine("Average:" + elements.Average(e => Convert.ToInt32(e.Element("BookPrice").Value)));
}</pre>调用函数：QueryElementByCoeompute(string xmlpath)
<pre name="code" class="csharp"> /// 查询元素并计算Price平均值
Program.QueryElementByCoeompute(@"C:\BookStore.xml");</pre>运行结果：
<img src="http://my.csdn.net/uploads/201204/21/1335012463_5700.png" alt="">
到此为止全部操作已经完成。整个操作仍然很简单。

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