返璞归真 asp.net mvc (1) - 添加、查询、更新和删除的 Demo

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Web;

namespace  MVC.Models
{
    /**//// <summary>
    /// MVC 之 Model
    /// Category 业务层逻辑
    /// </summary>
    public class CategeorySystem
    {
        // Northwind 的 ObjectContext
        private NorthwindEntities ctx = new NorthwindEntities();

        /**//// <summary>
        /// 获取 Category 列表
        /// </summary>
        /// <returns></returns>
        public List<Categories> GetCategory()
        {
            return ctx.Categories.ToList();
        }

        /**//// <summary>
        /// 获取 Category 实体
        /// </summary>
        /// <param name="categoryId">类别 ID</param>
        /// <returns></returns>
        public Categories GetCategory(int categoryId)
        {
            return ctx.Categories.FirstOrDefault(p => p.CategoryID == categoryId);
        }
    }
}

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Web;

namespace  MVC.Models
{
    /**//// <summary>
    /// MVC 之 Model
    /// Product 业务层逻辑
    /// </summary>
    public class ProductSystem
    {
        // // Northwind 的 ObjectContext
        private NorthwindEntities ctx = new NorthwindEntities();

        /**//// <summary>
        /// 获取产品列表
        /// </summary>
        /// <param name="pageIndex">页索引</param>
        /// <param name="pageSize">页大小</param>
        /// <returns></returns>
        public List<Products> GetProduct(int pageIndex, int pageSize)
        {
            return ctx.Products.OrderBy(p => p.ProductID).Skip(pageIndex * pageSize).Take(pageSize).ToList();
        }

        /**//// <summary>
        /// 获取产品
        /// </summary>
        /// <param name="productId">产品 ID</param>
        /// <returns></returns>
        public Products GetProduct(int productId)
        {
            return ctx.Products.FirstOrDefault(p => p.ProductID == productId);
        }

        /**//// <summary>
        /// 新增产品
        /// </summary>
        /// <param name="product">产品的 Entity</param>
        public void AddProduct(Products product)
        {
            ctx.AddToProducts(product);
        }

        /**//// <summary>
        /// 删除产品
        /// </summary>
        /// <param name="product">产品的 Entity</param>
        public void DeleteProduct(Products product)
        {
            product.Order_Details.Load();
            ctx.DeleteObject(product);
        }

        /**//// <summary>
        /// 在此对象的上下文中保存修改（增/删/改的操作）
        /// </summary>
        public void Save()
        {
            ctx.SaveChanges();
        }

        /**//// <summary>
        /// 在此对象的上下文中创建 EntityKey
        /// </summary>
        /// <param name="entitySetName">实体集的名称</param>
        /// <param name="entity">实体</param>
        /// <returns></returns>
        public System.Data.EntityKey CreateEntityKey(string entitySetName, object entity)
        {
            return ctx.CreateEntityKey(entitySetName, entity);
        }
    }
}

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Web;

namespace  MVC.Models
{
    /**//// <summary>
    /// 验证信息的实体
    /// </summary>
    public class ValidationEntity
    {
        /**//// <summary>
        /// 验证的错误信息
        /// </summary>
        public string ErrorMessage { get; set; }
        /**//// <summary>
        /// 产生错误信息的属性名称
        /// </summary>
        public string PropertyName { get; set; }
        
        public ValidationEntity(string errorMessage)
        {
            ErrorMessage = errorMessage;
        }

        public ValidationEntity(string errorMessage, string propertyName)
        {
            ErrorMessage = errorMessage;
            PropertyName = propertyName;
        }
    }
}

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Web;

namespace  MVC.Models
{
    /**//// <summary>
    /// 扩展 Product 实体
    /// 主要是为了对 Product 实体的各个属性做输入的合法性验证
    /// </summary>
    public partial class Products
    {
        List<ValidationEntity> info = new List<ValidationEntity>();

        /**//// <summary>
        /// 对 Product 实体所做的修改是否通过了合法性验证
        /// </summary>
        public bool IsValid
        {
            get 
            {
                return GetValidation().Count() == 0;
            }
        }
        
        /**//// <summary>
        /// 返回验证信息列表
        /// </summary>
        /// <returns></returns>
        public List<ValidationEntity> GetValidation()
        {
            return info;
        }

        /**//// <summary>
        /// 重写部分方法 OnProductNameChanging
        /// 用于在 ProductName 属性改变前，对其做合法性验证
        /// </summary>
        /// <param name="value"></param>
        partial void OnProductNameChanging(string value)
        {
            if (string.IsNullOrEmpty(value))
                info.Add(new ValidationEntity("请输入产品名称", "ProductName"));
        }

        /**//// <summary>
        /// 重写部分方法 OnUnitPriceChanging
        /// 用于在 UnitPrice 属性改变前，对其做合法性验证
        /// </summary>
        /// <param name="value"></param>
        partial void OnUnitPriceChanging(global::System.Nullable<decimal> value)
        {
            if (value == null)
                info.Add(new ValidationEntity("请输入单价", "UnitPrice"));
            else if (((decimal)value) > 100)
                info.Add(new ValidationEntity("输入的单价过高", "UnitPrice"));
        }
    }
}

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Web;
using  System.Web.Mvc;
using  System.Web.Mvc.Ajax;

using  MVC.Models;

namespace  MVC.Controllers
{
    /**//// <summary>
    /// MVC 之 Controller
    /// 这里体现了 Convention over Configuration
    /// Controller 类必须以字符串 Controller 做类名称的结尾，字符串 Controller 之前的字符串为 Controller 的名称，类中的方法名为 Action 的名称
    /// 例如 ProductController, Controller 的名称为：Product；其中的 Action 名称有 Index, Details, Edit 等
    /// </summary>
    public class ProductController : Controller // 需要继承自 System.Web.Mvc.Controller 或者实现 IController 接口
    {
        ProductSystem ps = new ProductSystem();

        // Action 的返回值必须为 ActionResult 或 void 

        /**//// <summary>
        /// 获取 Product 的列表
        /// </summary>
        /// <param name="pageIndex">页索引</param>
        /// <returns></returns>
        public ActionResult Index(int pageIndex)
        {
            int pageSize = 10;
            var products = ps.GetProduct(pageIndex, pageSize);

            // 此 Action 对应的 View 为（按查找的先后顺序） Views/Product/Index.aspx, Views/Product/Index.ascx, Views/Shared/Index.aspx, Views/Shared/Index.ascx
            // 其所对应的 View 的关联对象为 products
            return View("Index", products);
        }

        public ActionResult Details(int id)
        {
            var product = ps.GetProduct(id);

            if (product == null)
                return View("NotFound");
            else
                // 对应的 View 的名称默认为 Action 的名称，所以此处所对应的 View 的名称为 Details
                return View(product);
        }

        public ActionResult Edit(int id)
        {
            var product = ps.GetProduct(id);

            if (product == null)
            {
                return View("NotFound");
            }
            else
            {
                product.CategoriesReference.Load();

                // 编辑 Product 的时候需要在一个 DropDownList 中选择其所对应的 Category, 所以这里要构造一个名为 CategoryAll 的 ViewData
                // 因为 Categories 已经是 Product 的属性了，所以这里的 ViewData 的 key 不能为 Categories
                if (product.Categories == null)
                    ViewData["CategoryAll"] = new SelectList(new CategeorySystem().GetCategory(), "CategoryId", "CategoryName");
                else
                    ViewData["CategoryAll"] = new SelectList(new CategeorySystem().GetCategory(), "CategoryId", "CategoryName", product.Categories.CategoryID);

                return View("Edit", product);
            }
        }

        // 可以用 AcceptVerbs 来声明 Action 所对应的 http 方法
        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult Edit(int id, FormCollection formValues)
        {
            var product = ps.GetProduct(id);

            // 可以通过这种方式一一为 Product 对象的属性赋值
            // product.ProductName = Request.Form["ProductName"];

            // 也可以通过 UpdateModel, 让系统自动为属性赋值（通过反射的方式，取得对象的属性名称，然后和 Request 的 key 做匹配，匹配成功的则赋值）
            UpdateModel<Products>(product);

            var category = new CategeorySystem().GetCategory(int.Parse(Request.Form["MyCategory"]));
            product.CategoriesReference.EntityKey = ps.CreateEntityKey("Categories", category);

            // 通过以下的方式让 UpdateModel 只更新指定属性
            // string[] allowedProperties = new[] { "ProductName", "UnitPrice" };
            // UpdateModel(product, allowedProperties);

            if (!product.IsValid)
            {
                foreach (var validation in product.GetValidation())
                {
                    // 设置验证信息
                    ModelState.AddModelError(validation.PropertyName, validation.ErrorMessage);
                }

                if (product.Categories == null)
                    ViewData["CategoryAll"] = new SelectList(new CategeorySystem().GetCategory(), "CategoryId", "CategoryName");
                else
                    ViewData["CategoryAll"] = new SelectList(new CategeorySystem().GetCategory(), "CategoryId", "CategoryName", product.Categories.CategoryID);

                return View(product);
            }

            ps.Save();

            // 跳转到指定的 Action
            return RedirectToAction("Details", new { id = product.ProductID });
        }

        public ActionResult Create()
        {
            Products product = new Products()
            {
                ProductName = "请输入产品名称"
            };

            return View(product);
        }

        // 可以为参数添加声明，如下例：[Bind(Include = "ProductName")]，客户端提交的数据中，只有 ProductName 会被绑定到 Product 对象上
        // [Bind(Include = "ProductName")] 这样的 attribute 也可以声明在类上，用于指定类中需要被绑定的属性
        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult Create([Bind(Include = "ProductName")] Products product)
        {
            if (!product.IsValid)
            {
                foreach (var issue in product.GetValidation())
                {
                    ModelState.AddModelError(issue.PropertyName, issue.ErrorMessage);
                }

                return View(product);
            }

            ps.AddProduct(product);
            ps.Save();

            return RedirectToAction("Details", new { id = product.ProductID });
        }

        public ActionResult Delete(int id)
        {
            var product = ps.GetProduct(id);

            if (product == null)
                return View("NotFound");
            else
                return View(product);
        }

        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult Delete(int id, string confirmButton)
        {
            var product = ps.GetProduct(id);

            if (product == null)
                return View("NotFound");

            ps.DeleteProduct(product);
            ps.Save();

            return View("Deleted");
        }
    }
}

<% @ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<IEnumerable<MVC.Models.Products>>"  %>

< asp:Content  ID ="Content1"  ContentPlaceHolderID ="TitleContent"  runat ="server" >
    Index
</ asp:Content >
< asp:Content  ID ="Content2"  ContentPlaceHolderID ="MainContent"  runat ="server" >
     < h2 >
        Index </ h2 >
     < table >
         < tr >
             < th >
             </ th >
             < th >
                ProductID
             </ th >
             < th >
                ProductName
             </ th >
             < th >
                UnitPrice
             </ th >
         </ tr >
         <%   // 因为本页集成了 System.Web.Mvc.ViewPage<IEnumerable<MVC.Models.Products>>
            // 所以这里的 Model 就是 System.Web.Mvc.ViewPage<IEnumerable<MVC.Models.Products>> 的 Model 属性
            foreach (var item in Model)
            {  %>
         < tr >
             < td >
                 <!-- 这里的 Html 属性类型为 System.Web.Mvc.HtmlHelper -->
                 <% =  Html.ActionLink( " Delete " ,  " Delete " ,  new  { id  =  item.ProductID }) %>
                |
                 <% =  Html.ActionLink( " Edit " ,  " Edit " ,  new  { id  =  item.ProductID })  %>
             </ td >
             < td >
                 <% =  Html.ActionLink(item.ProductID.ToString(),  " Details " ,  new  { id = item.ProductID }) %>
             </ td >
             < td >
                 <% =  Html.Encode(item.ProductName)  %>
             </ td >
             < td >
                 <% =  Html.Encode( String .Format( " {0:F} " , item.UnitPrice))  %>
             </ td >
         </ tr >
         <%  }  %>
     </ table >
     < p >
         <% =  Html.RouteLink( " 上一页 " ,  " Products " ,  new  { pageIndex  =  Convert.ToInt32(Html.ViewContext.RouteData.Values[ " pageIndex " ])  -   1  }) %>
        |
         <% =  Html.RouteLink( " 下一页 " ,  " Products " ,  new  { pageIndex  =  Convert.ToInt32(Html.ViewContext.RouteData.Values[ " pageIndex " ])  +   1  }) %>
     </ p >
</ asp:Content >