MVC学习笔记_ORM_框架_解耦

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ORM （Object Relational Mapping）

EF
匿名表达式：筛选部分列

db.UserInfo.Where<UserInfo>(u=>u.Id==1).Select(c=>new{Name=c.UserName,Pwd=c.UserPwd});

MVC

HTMLHelper

<%=Html.ActionLink("首页","Index")%>

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//等号输出=渲染Html标签<%=Html.ActionLink("首页","Index")%>//冒号输出：Server.HtmlEncode 操作 (纯文本输出)//可避免XSS攻击<%:Html.ActionLink("首页","Index")%>

自带的Ajax方法

<%using(Ajax.BeginForm("Index",new AjaxOptions{Confirm="确定？",InsertionMode=System.Web.Mvc.Ajax.InsertionMode.Replace,UpdateTargetId="div1"}))%>

分页
- HTmlHelper 扩展：分页 //可简单引入样式

        HtmlHelper的扩展：        注意点：扩展方法必须是静态方法，所在的类必须是静态类，所在的命名空间改成System.Web.MVC则能省略页面中必须添加命名空间的约束。        //主要就是输出分页的超级链接的标签        //自定义分页Helper扩展        public static HtmlString ShowPageNavigate(this HtmlHelper htmlHelper, int currentPage, int pageSize, int totalCount)        {            var redirectTo = htmlHelper.ViewContext.RequestContext.HttpContext.Request.Url.AbsolutePath;            pageSize = pageSize == 0 ? 3 : pageSize;            var totalPages = Math.Max((totalCount + pageSize - 1) / pageSize, 1); //总页数            var output = new StringBuilder();            if (totalPages > 1)            {                //if (currentPage != 1)                {//处理首页连接                    output.AppendFormat("<a class='pageLink' href='{0}?pageIndex=1&pageSize={1}'>首页</a> ", redirectTo, pageSize);                }                if (currentPage > 1)                {//处理上一页的连接                    output.AppendFormat("<a class='pageLink' href='{0}?pageIndex={1}&pageSize={2}'>上一页</a> ", redirectTo, currentPage - 1, pageSize);                }                else                {                   // output.Append("<span class='pageLink'>上一页</span>");                }                output.Append(" ");                int currint = 5;                for (int i = 0; i <= 10; i++)                {//一共最多显示10个页码，前面5个，后面5个                    if ((currentPage + i - currint) >= 1 && (currentPage + i - currint) <= totalPages)                    {                        if (currint == i)                        {//当前页处理                            //output.Append(string.Format("[{0}]", currentPage));                            output.AppendFormat("<a class='cpb' href='{0}?pageIndex={1}&pageSize={2}'>{3}</a> ", redirectTo, currentPage , pageSize, currentPage );                        }                        else                        {//一般页处理                            output.AppendFormat("<a class='pageLink' href='{0}?pageIndex={1}&pageSize={2}'>{3}</a> ", redirectTo, currentPage + i - currint, pageSize, currentPage + i - currint);                        }                    }                    output.Append(" ");                }                if (currentPage < totalPages)                {//处理下一页的链接                    output.AppendFormat("<a class='pageLink' href='{0}?pageIndex={1}&pageSize={2}'>下一页</a> ", redirectTo, currentPage + 1, pageSize);                }                else                {                    //output.Append("<span class='pageLink'>下一页</span>");                }                output.Append(" ");                if (currentPage != totalPages)                {                    output.AppendFormat("<a class='pageLink' href='{0}?pageIndex={1}&pageSize={2}'>末页</a> ", redirectTo, totalPages, pageSize);                }                output.Append(" ");            }            output.AppendFormat("第{0}页 / 共{1}页", currentPage, totalPages);//这个统计加不加都行            return new HtmlString(output.ToString());        }        //样式部分：        body{}.paginator{    font: 12px Arial, Helvetica, sans-serif;    padding: 10px 20px 10px 0;    margin: 0px;}.paginator a{    border: solid 1px #ccc;    color: #0063dc;    cursor: pointer;    text-decoration: none;}.paginator a:visited{    padding: 1px 6px;    border: solid 1px #ddd;    background: #fff;    text-decoration: none;}.paginator .cpb{    border: 1px solid #F50;    font-weight: 700;    color: #F50;    background-color: #ffeee5;}.paginator a:hover{    border: solid 1px #F50;    color: #f60;    text-decoration: none;}.paginator a, .paginator a:visited, .paginator .cpb, .paginator a:hover{    float: left;    height: 16px;    line-height: 16px;    min-width: 10px;    _width: 10px;    margin-right: 5px;    text-align: center;    white-space: nowrap;    font-size: 12px;    font-family: Arial,SimSun;    padding: 0 3px;}

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架构构建

引用 Model 需引用 EntityFramework & Date.Entity;
DBSession
- 数据访问会话层，负责创建所有的数据操作类对象，业务层制药获取到DBSession，就拿到了所有的数据操作类的实例，让业务层与数据层进行解耦。
- ExecuteSql 执行特殊sql语句
- 数据层不再执行SaveChanges

  public class DBSession:IDBSession    {        DbContext db = new ReportServerEntities();        private Users _usersDAL;        public Users UsersDAL        {            get            {                if (_usersDAL == null)                {                    _usersDAL = AbstractFactory.CreateUsers();//抽象工程                }                return _usersDAL;            }            set { _usersDAL = value; }        }        /// <summary>        /// 执行特殊sql语句        /// </summary>        /// <param name="sql"></param>        /// <param name="pars"></param>        /// <returns></returns>        public int ExecuteSql(string sql, params SqlParameter pars)        {            return db.Database.ExecuteSqlCommand(sql, pars);        }        public int SaveChanges()        {            return db.SaveChanges();        }    }

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DbContextFactory

负责创建EF上下文对象、保证线程内唯一、多次请求只创建一个对象

    public class DbContextFactory    {        public static DbContext GetCurrentDbContext()        {            DbContext dbContext = (DbContext)CallContext.GetData("DbContext");            if (dbContext==null)            {                dbContext =  new ReportServerEntities();                CallContext.SetData("DbContext", dbContext);            }             return dbContext;        }     }

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封装Base注意项_IEnumerable

System.Linq.Expressions.Expression<>
IEnumerable 直接获取数据
IQueryable 转换为Sql语句、使用时再进行获取数据

//默认直接获取  IEnumerable  IQueryable<T> LoadEntities(Func<T, bool> whereLambda);//获取         IQueryable  IQueryable<T> LoadEntities(System.Linq.Expressions.Expression<Func<T, bool>> whereLambda);

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