1. 读取XML文件
XDocument和XElement类都提供了导入XML文件的Load()方法，可以读取XML文件的内容，并转换为XDocument或XElement类的实例。
示例XML文件：Product.xml
<?xml version="1.0" encoding="utf-8"?>
<Products>
<Product>
<ProductID>1</ProductID>
<ProductName>LINQ to XML</ProductName>
<UnitPrice>10</UnitPrice>
</Product>
<Product>
<ProductID>2</ProductID>
<ProductName>LINQ to SQL</ProductName>
<UnitPrice>20</UnitPrice>
</Product>
</Products>
XElement root = XElement.Load(Server.MapPath("Product.xml"));
2. 查询根元素
XDocument doc = XDocument.Load(Server.MapPath("Product.xml"));
IEnumerable<XElement> elements = from e in doc.Elements("Products")
select e;
foreach (XElement e in elements)
{
Console.WriteLine("{0}-{1}", e.Name, e.Value);
}
XDocument doc = XDocument.Load(Environment.CurrentDirectory + @"\Product.xml");
IEnumerable<XElement> elements = from e in doc.Elements("Products")
select e;
foreach (XElement e in elements)
{
Console.WriteLine("{0}-{1}", e.Name, e.Value);
}
3. 查询节点
XDocument doc = XDocument.Load(Environment.CurrentDirectory + @"\" + "Product.xml");
var query = from p in doc.Element("Products").Elements("Product")
where (int)p.Element("ProductID") ==
select p; query.ToList().ForEach(item =>
{
Console.WriteLine("{0}-{1}-{2}", item.Element("ProductID").Value, item.Element("ProductName").Value, item.Element("UnitPrice").Value);
});
XElement xml = XElement.Load(Environment.CurrentDirectory + @"\" + "Product.xml");
var query = from p in xml.Elements("Product")
where (int)p.Element("ProductID") ==
select p;
4. 查询子孙节点
Descendants轴方法与Elements类型，不过Elements只查找当前元素下的直接子节点，而Descendants则会遍历当前元素下任意层级的子元素。
示例xml文件:
<?xml version="1.0" encoding="utf-8"?>
<Products>
<Product>
<Book>
<ProductID>1</ProductID>
<ProductName>LINQ to XML</ProductName>
<UnitPrice>10</UnitPrice>
</Book>
</Product>
<Product>
<Book>
<ProductID>2</ProductID>
<ProductName>LINQ to SQL</ProductName>
<UnitPrice>20</UnitPrice>
</Book>
</Product>
</Products>
使用Descendants()方法查询：
XElement root = XElement.Load(Environment.CurrentDirectory + @"\" + "Product.xml");
var query = from b in root.Descendants("Book")
select b;
foreach (var item in query)
{
Console.WriteLine(item.Element("ProductName").Value);
}
5. 查询属性
示例xml文件：
<?xml version="1.0" encoding="utf-8"?>
<Products>
<Product ID="1">
<ProductID>1</ProductID>
<ProductName>LINQ to XML</ProductName>
<UnitPrice>10</UnitPrice>
</Product>
<Product ID="2">
<ProductID>2</ProductID>
<ProductName>LINQ to SQL</ProductName>
<UnitPrice>20</UnitPrice>
</Product>
</Products>
XElement xml = XElement.Load(Environment.CurrentDirectory + @"\" + "Product.xml");
var query = from p in xml.Elements("Product")
where (int)p.Attribute("ID") ==
select p;
XElement xml = XElement.Load(Environment.CurrentDirectory + @"\" + "Product.xml");
var query = from p in xml.Elements("Product")
where (int)p.Attribute("ID") ==
select new
{
ID = p.Attribute("ID").Value,
ProductID = p.Element("ProductID").Value,
ProductName = p.Element("ProductName").Value
};
XElement xml = XElement.Load(Environment.CurrentDirectory + @"\" + "Product.xml");
var query = from p in xml.Nodes().OfType<XElement>()
where (int)p.Attribute("ID") ==
select new
{
ID = p.Attribute("ID").Value,
ProductID = p.Element("ProductID").Value,
ProductName = p.Element("ProductName").Value
};