关于Linq的query类型的认识

                 var query =
                 from c in Customers
                 where c.Country == "USA"
                 select new { c.CompanyName,c.Country};
//查看query的类型

System.Data.Linq.DataQuery`1[[<>f__AnonymousType0`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]], ConsoleApplication1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]

里面包含了 System.Data.Linq.DataQuery`1[String，String] 

 foreach (var company in query)
            {
                Console.WriteLine(company.GetType());
                Console.WriteLine(company);
            }

而company的类型如下，可以简化看成[String,String]

<>f__AnonymousType0`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]

并且如上的foreach代码则在实际执行中，等价于如下代码：

 //IEnumerator<string> enumerator = query.GetEnumerator();
 var enumerator = query.GetEnumerator();   //用var代替IEnumerator<string>，因为上面查询的是new形式select new { c.CompanyName,c.Country};

while (enumerator.MoveNext())
 {
       Console.WriteLine(enumerator.Current);
 }