LINQ 从 CSV 文件生成 XML

本文参考：http://msdn.microsoft.com/zh-cn/library/bb387090.aspx

下面的代码对字符串数组执行 LINQ 查询。
在 C# 版本中，该查询使用 let 子句将每个字符串分隔成字段数组。
C#VB
// 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);
这段代码产生以下输出：
XML
<Root>
  <Customer CustomerID="GREAL">
    <CompanyName>Great Lakes Food Market</CompanyName>
    <ContactName>Howard Snyder</ContactName>
    <ContactTitle>Marketing Manager</ContactTitle>
    <Phone>(503) 555-7555</Phone>
    <FullAddress>
      <Address>2732 Baker Blvd.</Address>
      <City>Eugene</City>
      <Region>OR</Region>
      <PostalCode>97403</PostalCode>
      <Country>USA</Country>
    </FullAddress>
  </Customer>
  <Customer CustomerID="HUNGC">
    <CompanyName>Hungry Coyote Import Store</CompanyName>
    <ContactName>Yoshi Latimer</ContactName>
    <ContactTitle>Sales Representative</ContactTitle>
    <Phone>(503) 555-6874</Phone>
    <FullAddress>
      <Address>City Center Plaza 516 Main St.</Address>
      <City>Elgin</City>
      <Region>OR</Region>
      <PostalCode>97827</PostalCode>
      <Country>USA</Country>
    </FullAddress>
  </Customer>
  <Customer CustomerID="LAZYK">
    <CompanyName>Lazy K Kountry Store</CompanyName>
    <ContactName>John Steel</ContactName>
    <ContactTitle>Marketing Manager</ContactTitle>
    <Phone>(509) 555-7969</Phone>
    <FullAddress>
      <Address>12 Orchestra Terrace</Address>
      <City>Walla Walla</City>
      <Region>WA</Region>
      <PostalCode>99362</PostalCode>
      <Country>USA</Country>
    </FullAddress>
  </Customer>
  <Customer CustomerID="LETSS">
    <CompanyName>Let's Stop N Shop</CompanyName>
    <ContactName>Jaime Yorres</ContactName>
    <ContactTitle>Owner</ContactTitle>
    <Phone>(415) 555-5938</Phone>
    <FullAddress>
      <Address>87 Polk St. Suite 5</Address>
      <City>San Francisco</City>
      <Region>CA</Region>
      <PostalCode>94117</PostalCode>
      <Country>USA</Country>
    </FullAddress>
  </Customer>
</Root>

　　二、LINQ 从XML文件中生成csv格式的文本文件

http://msdn.microsoft.com/zh-cn/library/bb387094.aspx

本示例的 C# 版本使用方法语法和 Aggregate 运算符通过一个表达式从 XML 文档生成 CSV 文件。 有关更多信息，请参见LINQ 中的查询语法和方法语法 (C#)。
Visual Basic 版本使用过程代码将字符串集合聚合为一个字符串。
本示例使用下面的 XML 文档：示例 XML 文件：Customers 和 Orders (LINQ to XML)。
C#VB
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);
这段代码产生以下输出：
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