Linq to Entity-执行存储过程

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1.在model中创建存储过程Model，将存储过程与实体进行映射，名称为存储过程名_Result:其中的属性是存储过程的返回值

create procedure "Ten Most Expensive Products" AS  SET ROWCOUNT 10SELECT Products.ProductName AS TenMostExpensiveProducts, Products.UnitPrice  FROM Products  ORDER BY Products.UnitPrice DESC

    public partial class Ten_Most_Expensive_Products_Result    {        public string TenMostExpensiveProducts { get; set; }        public Nullable<decimal> UnitPrice { get; set; }    }

2.在DbContext子类中创建执行方法:传递存储过程名：Ten_Most_Expensive_Products

       public virtual ObjectResult<Ten_Most_Expensive_Products_Result> Ten_Most_Expensive_Products()        {            return ((IObjectContextAdapter)this).ObjectContext.ExecuteFunction<Ten_Most_Expensive_Products_Result>("Ten_Most_Expensive_Products");        }

3.测试执行存储过程：

        static void TestProc()        {            using (NorthwindEntities NWEntities = new TestLINQToEntitiesApp.NorthwindEntities())            {                IEnumerable<Ten_Most_Expensive_Products_Result> tenProducts = from p in                                  NWEntities.Ten_Most_Expensive_Products()                                  select p;                foreach (Ten_Most_Expensive_Products_Result p in tenProducts)                {                    Console.WriteLine("Product Name: {0}, Price: {1}", p.TenMostExpensiveProducts, p.UnitPrice);                }            }                   }

4.如果存储过程返回的实体在model中已经存在了，则可以不用新建一个model, 直接利用原来的Model，并直接在Dbcontext子类中创建执行方法：

Create PROCEDURE [dbo].[GetProduct]   (   @ProductID int   ) AS   SET NOCOUNT ON   Select * from Products where ProductID = @ProductID

       public virtual ObjectResult<Product> GetProduct(Nullable<int> productID)        {            var productIDParameter = productID.HasValue ?                new ObjectParameter("ProductID", productID) :                new ObjectParameter("ProductID", typeof(int));                return ((IObjectContextAdapter)this).ObjectContext.ExecuteFunction<Product>("GetProduct", productIDParameter);        }

Product getProduct = NWEntities.GetProduct(1).FirstOrDefault();

此时由GetProduct得到的product是与Dbcontext关联的，对它进行任何操作都会执行数据库操作从而修改数据库的数据。

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