LinQ各种方式查询、组合查询、IQueryable集合类型

1、模糊查询（包含）

Repeater1.DataSource = con.car.Where(r =>r.name.Contains(s)).ToList();

2、开头查询

Repeater1.DataSource = con.car.Where(r =>r.name.StartsWith(s)).ToList();

3、结尾查询

Repeater1.DataSource = con.car.Where(r =>r.name.EndsWith(s)).ToList();

4、个数显示

IEnumerable<car> clist = con.car;
int count =clist.Count;

5、最大最小值平均值

con.car.Max(r => r.price);
con.car.Min(r => r.price);
con.car.Average(r => r.price);

6、求和、升序、降序

con.car.Sum(r => r.price);
Repeater1.DataSource = con.car.OrderBy(r => r.price);
Repeater1.DataSource = con.car.OrderByDescending(r => r.price);

7、分页

　　集合的Skip方法：跳过多少条数据

　　Take方法：取前多少条数据　　

int count = 4;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            using (Data0928DataContext con = new Data0928DataContext())
            {
                Repeater1.DataSource = con.Users.Take(count).ToList();
                Repeater1.DataBind();
            }
        }
    }

8、组合查询

using (DataClassesDataContextcon = new DataClassesDataContext())
        {
            IQueryable<Users> ulist = con.Users;
            if (name.Length > 0)
            {
                ulist = ulist.Where(r => r.UserName.Contains(name));
            }
            if (nick.Length > 0)
            {
                ulist = ulist.Where(r => r.NickName.Contains(nick));
            }
           if (brt.Length > 0)
        {
            string aa = DropDownList1.SelectedValue;
            if (aa == "=")
                clist = clist.Where(r => Convert.ToDateTime(r.birthday).Year == Convert.ToInt32(brt));
            if (aa == ">")
                clist = clist.Where(r => Convert.ToDateTime(r.birthday).Year >Convert.ToInt32(brt));
            if (aa == "<")
                clist = clist.Where(r => Convert.ToDateTime(r.birthday).Year < Convert.ToInt32(brt));
        }
            Repeater1.DataSource = ulist.Take(count);
            Repeater1.DataBind();
        }    

9、集合的交集

　　集合的Intersect方法，取两个集合的交集

var allList = nameList.Intersect(brandList);