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  • MVC中对VIEW的理解,通过前台BaseController来理解面向对象

    首先它是一个具有返回类型为ViewResult的一个方法,也就是说,我们可以通过返回ViewResult对象来代替View()方法,下面的操作是合法的
         ViewData.Model = model;
                return new ViewResult
                {
                    ViewName = viewName,
                    MasterName = this.MasterFile,
                    ViewData = ViewData,
                    TempData = TempData
                };
        它在一般情况下等同于return view(model),这是微软为我们封装好的方法,让我们省去了不少代码,它的view(object model)方法原型可能是这样的
            protected internal ViewResult View(object model)
            {
              ViewData.Model = model;
                return new ViewResult
                {
                    ViewName = viewName,
                    MasterName = this.MasterFile,
                    ViewData = ViewData,
                    TempData = TempData
                };
            }
            呵呵,我们有时,希望在后台通过调用masterfile的方法来动态改变模版页,可以这样来实现
          public abstract class BaseController : Controller
           {
            /// <summary>
            /// 根据用户角色,返回它的模版页
            /// 子类可以直接访问本属性
            /// </summary>
            protected string MasterFile
            {
                get
                {
                    return UIHelper.GetMasterPage(Tsingda.XXB.Common.WebSession.UserRole);
                }
            }
            /// <summary>
            /// 重写controller的View方法,使它可以根据用户角色应用指定视图
            /// </summary>
            protected new ViewResult View(string viewName, object model)
            {
                ViewData.Model = model;
                return new ViewResult
                {
                    ViewName = viewName,
                    MasterName = this.MasterFile,
                    ViewData = ViewData,
                    TempData = TempData
                };
            }
     }

       /// <summary>
        /// 前台通用方法
        /// </summary>
        public partial class UIHelper
        {
            /// <summary>
            /// 根据用户角色,得到指定的模板
            /// <param name="role"></param>
            /// <returns></returns>
            public static string GetMasterPage(Tsingda.XXB.Common.CustomEnum.UserRole role)
            {
                string masterPageFile = "";
                switch (role)
                {
                    case Common.CustomEnum.UserRole.Student:
                        masterPageFile = "~/Views/Shared/StudentCenter.Master";
                        break;
                    case Common.CustomEnum.UserRole.Teacher:
                        masterPageFile = "~/Views/Shared/TeacherCenter.Master";
                        break;
                    case Common.CustomEnum.UserRole.Parents:
                        masterPageFile = "~/Views/Shared/ParentCenter.Master";
                        break;
                    case Common.CustomEnum.UserRole.Agents:
                        break;
                    case Common.CustomEnum.UserRole.Visitor:
                        masterPageFile = "~/Views/Shared/StudentCenter.Master";
                        break;
                }
                return masterPageFile;
            }
    }

    而在同一个controller中,如果你的View视图不希望去应用任何模板页,可以写这样一个方法,呵呵
          /// <summary>
            /// 返回没有母板页的视图
            /// </summary>
            /// <param name="model"></param>
            /// <returns></returns>
            protected ViewResult ViewNotMasterFile(object model)
            {
                ViewData.Model = model;
                return new ViewResult
                {
                    MasterName = string.Empty,
                    ViewData = ViewData,
                    TempData = TempData
                };
            }
    呵呵,多么灵活法,(因为ASCX视图不能有母板页的,呵呵)

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  • 原文地址:https://www.cnblogs.com/lori/p/2235756.html
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