Linq语句简单应用

    select p;
    q.Dump();
//查询
    var w= from p in Products
           where p.CateoryId==1
           select new {p.ProductName,p.UnitPrice};
    w.Dump();
//按照是否供应分组，显示数量
    var hh= from p in Products
           group p by p.IsAbord into g
           select new {g.Key,Nums=g.Count()};
//按类别分组，显示数量
    var ww= from p in Products
           group p by p.Category.CategoryName into g
           select new {g.Key,Nums=g.Count()};
//阻抗失调,所有数据文件都用from读写
    var xml=new XElement("Products",
          from p in Products
          select new XElement("Product",
          new XElement("ProductName",p.ProductName),
          new XElement("UnitPrice",p.UnitPrice),
          new XAttribute("Category",p.Category.CategoryName))
          );
    xml.Dump();
    xml.Save(@"E:\Products.xml");
//XML文档查询
xml.Elements("Product").Where(e=>e.Element("ProductName").Value.Contains("肉")).Dump();//XML代表根节点
//新增
    Shipper s=new Shipper{ShipperName="EMS",Tel="010-12345678"};
    Shippers.InsertOnSubmit(s);
    SubmitChanges();
//修改
    Shippers.FirstOrDefault(s=>s.ShipperId==5).ShipperName="EMSEMS";
    SubmitChanges();
//删除
    Shipper sss=Shippers.FirstOrDefault(sh=>sh.ShipperId==6);
    Shippers.DeleteOnSubmit(sss);
    SubmitChanges();
//批量删除
    var qq=Shippers.Where(sq=>sq.ShipperId>=3);
    Shippers.DeleteAllOnSubmit(qq);
// Define other methods and classes here