首先在Program.cs的Main()方法下添加如下代码：
string[]
names = { "heh", "haha", "huahua", "kuku" };
1、取得以h开头的名称：
(查询语法)
var queryResult = from n in names
where
n.StartsWith("h")
select n;
(方法语法)
var queryResult = names.Where(n =>
n.StartsWith("h"));
2、将查询结果排序
(降序):
(查询语法,由于首字母一样，所以按第二个字母的顺序进行降序)
var queryResult = from n in names
where
n.StartsWith("h")
orderby n descending
select n;
(方法语法)
var queryResult =
names.Where(n=>n.StartsWith("h")).OrderByDescending(n=>n);
在Main()方法中添加如下代码：
int[]
numbers = {2,4,5,1,55,11,32,134,11,333,245 };
1、找出大于100的数：
(查询语法)
var queryResult = from n in numbers
where n
> 100
select n;
(方法语法)
var queryResult = numbers.Where(n=>n>100);
2、分别输出结果的个数，结果中的最小值，结果中的最大值，数字结果的平均值，所有数字结果的总和：
Console.WriteLine("结果的个数:"+queryResult.Count());
Console.WriteLine("结果中的最小值:"+queryResult.Min());
Console.WriteLine("结果中的最大值:"+queryResult.Max());
Console.WriteLine("结果中的平均值:"+queryResult.Average());
Console.WriteLine("数字结果的总和:"+queryResult.Sum());
查询复杂对象，在Program类的开头，给Customer类添加如下类定义:
class Customer
{
public string ID { get; set; }
public string City { get; set; }
public string Country { get; set; }
public string Region { get; set; }
public decimal Sales { get; set; }
public override string ToString()
{
return "ID:" + ID + "City:" + City + "Country:" + Country + "Region:"
+ Region + "Sales:" + Sales;
}
}
在Main()方法中添加如下代码：
List<Customer> customers = new List<Customer> {
new Customer{ID="A",City="New
York1",Country="USA1",Region="North1",Sales=111},
new Customer{ID="B",City="New
York2",Country="USA2",Region="North2",Sales=222},
new Customer{ID="C",City="New
York3",Country="USA3",Region="North3",Sales=333},
new Customer{ID="D",City="New
York4",Country="USA4",Region="North4",Sales=444},
new Customer{ID="E",City="New
York5",Country="USA5",Region="North5",Sales=555},
new Customer{ID="F",City="New
York6",Country="USA6",Region="North6",Sales=666},
new Customer{ID="G",City="New
York7",Country="USA7",Region="North7",Sales=777}
};
1、选择来自North1的顾客：
(查询语法)
var queryResults = from c in customers
where c.Region == "North1"
select c;
(方法语法)
var queryResults = customers.Where(n=>n.Region=="North1");
2、投射--在查询中创建新的对象：
(查询语法)
var queryResults = from c in customers
where c.Region == "North7"
select new
{c.City,c.Country,c.ID };
(方法语法,在查询语法中需要select子句，但在之前的例子中没有看到Select()方法，因为在Linq方法语法中不需要它，除非在进行投射)
var queryResults = customers.Where(n => n.Region == "North7").Select(c
=> new {c.City,c.Country,c.ID });
3、投射--单值选择查询(取得不重复的Region值)
(查询语法)
var queryResults=(from n in customers select c.Region).Distinct();
(方法语法)
var queryResults=customers.Select(c=>c.Region).Distinct();