ASP.NET Core 一步步搭建个人网站（3）_菜单管理

2018-06-22 07:55:27来源：未知阅读 ()

上一章，我们实现了用户的注册和登录，登录之后展示的是我们的主页，页面的左侧是多级的导航菜单，定位并展示用户需要访问的不同页面。目前导航菜单是写死的，考虑以后菜单管理的便捷性，我们这节实现下可视化配置菜单的功能，这样以后我们可以动态的配置导航菜单，不用再编译发布网站程序了。

增加后台管理模块

第1步，左侧导航菜单中，添加后台管理模块，用作管理员登录后，可以进行一些后台管理的操作，当然，目前还没有权限控制（后期加入），所以对所有用户可见。大概菜单结构如下：

有了菜单项，我们还需要控制视图的跳转，所以，接下来需要写对应的控制器和视图。

为了将相关功能组织成一组单独命名空间（路由）和文件夹结构（视图），解决方案中右键添加区域（Area）,取名后台管理（Configuration），代表后台管理模块，.Net Core脚手架（scaffold）自动帮我们实现了目录划分：控制器（Controllers）、模型（Models）、视图（Views）

菜单模型定义

菜单的基本属性有：菜单名称、菜单类型、菜单的图标样式、菜单url路径。另外，菜单在逻辑上是树状结构，但是要在物理数据库中存储，需要进行扁平化处理，每个菜单项有个父菜单属性（根节点的父菜单为空），还有同一父节点底下，在组类的排序属性，定义如下：

 1 /// <summary>
 2 /// 菜单
 3 /// </summary>
 4 public class Menu
 5 {
 6     /// <summary>
 7     /// 主键ID
 8     /// </summary>
 9     [DatabaseGenerated(DatabaseGeneratedOption.None)]
10     [Required(ErrorMessage = "请输入菜单编号")]
11     public string Id { get; set; }
12 
13     /// <summary>
14     /// 菜单名称
15     /// </summary>
16     [Required(ErrorMessage = "请输入菜单名称")]
17     [StringLength(256)]
18     public string Name { get; set; }
19 
20     /// <summary>
21     /// 父级ID
22     /// </summary>
23     [DisplayFormat(NullDisplayText = "无")]
24     public string ParentId { get; set; }
25 
26     /// <summary>
27     /// 菜单组内排序
28     /// </summary>
29     [Range(0, 99, ErrorMessage = "请选择1-99范围内的整数")]
30     public int IndexCode { get; set; }
31 
32     /// <summary>
33     /// 菜单路径
34     /// </summary>
35     [StringLength(256)]
36     [DisplayFormat(NullDisplayText = "无")]
37     public string Url { get; set; }
38 
39     /// <summary>
40     /// 类型：0导航菜单；1操作按钮。
41     /// </summary>
42     [Required(ErrorMessage = "请选择菜单类型")]
43     public MenuTypes? MenuType { get; set; }
44 
45     /// <summary>
46     /// 菜单图标名称
47     /// </summary>
48     [Required(ErrorMessage = "请输入菜单图标")]
49     [StringLength(50)]
50     public string Icon { get; set; }
51 
52     /// <summary>
53     /// 菜单备注
54     /// </summary>
55     public string Remarks { get; set; }
56 }
57 /// <summary>
58 /// 菜单类型
59 /// </summary>
60 public enum MenuTypes
61 {
62     /// <summary>
63     /// 导航菜单
64     /// </summary>
65     导航菜单,
66     /// <summary>
67     /// 操作菜单
68     /// </summary>
69     操作菜单
70 }

有了我们的菜单模型，在控制器目录中，我们右键建立第1个自己的控制器，取名MenuController，用来菜单管理，上下文选取定义好的Menu模型，还是利用脚手架，自动帮我们生成增删改查对应的后来逻辑和视图。此时，我们把菜单导向该控制器，其实是可以正常访问的，不过还远远达不到我们的要求，所以我们还得完善下自动生成的代码。

菜单控制器改写

为了方便今后的拓展，新增一个AppController控制器，继承Controller，以后所有的控制器，都继承于AppController，方便一些公共的方法调用。

.Net Core有个比较方便的一点，就是实现了构造器的依赖注入，这样我们不用像以前那样手工New一个DBContext对象，直接在控制器将需要的DBContext注入，调用的时候，直接访问注入的对象即可，有关依赖注入的知识，这里就不在多说了，有兴趣大家可以了解一下：.Net Core依赖注入

首先，在ApplicationDbContext添加Menu数据集

 1 public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
 2 {
 3     public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
 4         : base(options)
 5     {
 6     }
 7 
 8     protected override void OnModelCreating(ModelBuilder builder)
 9     {
10         base.OnModelCreating(builder);
11     }
12 
13     public DbSet<ApplicationUser> ApplicationUsers { get; set; }
14 
15     public DbSet<Menu> Menus { get; set; }
16 }

这里我们修改下MenuController构造器：

1 private readonly ApplicationDbContext _context;
2 
3 public MenuController(ApplicationDbContext context, INavMenuService navMenuService)
4 {
5     _context = context;
6     _NavMenuService = navMenuService;
7 }

为了后面方便统一提供下拉框选择，这里实现一个下拉框初始化方法：

 1 /// <summary>
 2 /// 初始化下拉选择框
 3 /// </summary>
 4 /// <param name="menu"></param>
 5 private void UpdateDropDownList(Menu menu = null)
 6 {
 7     var menusParent = _context.Menus.AsNoTracking().Where(s => s.MenuType == MenuTypes.导航菜单);
 8     List<SelectListItem> listMenusParent = new List<SelectListItem>();
 9     foreach (var menuParent in menusParent)
10     {
11         listMenusParent.Add(new SelectListItem
12         {
13             Value = menuParent.Id,
14             Text = menuParent.Id + $"({menuParent.Name})",
15             Selected = (menu != null && menuParent.Id == menu.ParentId)
16         });
17     }
18     ViewBag.ParentIds = listMenusParent;
19 
20     if (menu == null)
21     {
22         ViewBag.MenuTypes = MenuTypes.导航菜单.GetSelectListByEnum();
23     }
24     else
25     {
26         ViewBag.MenuTypes = MenuTypes.导航菜单.GetSelectListByEnum(Convert.ToInt32(menu.MenuType));
27     }
28 }

列表页改写

控制器调整：增加查询传入参数，根据参数筛选查询结果；

 1 /// <summary>
 2 /// 列表页
 3 /// </summary>
 4 /// <param name="query"></param>
 5 /// <returns></returns>
 6 public async Task<IActionResult> Index(MenuIndexQuery query)
 7 {
 8     var menus = _context.Menus.AsNoTracking();
 9     if (!string.IsNullOrEmpty(query.QName))
10     {
11         menus = menus.Where(s => s.Name.Contains(query.QName.Trim()));
12     }
13     if (!string.IsNullOrEmpty(query.QId))
14     {
15         menus = menus.Where(s => s.Id.Contains(query.QId.Trim()));
16     }
17     if (!string.IsNullOrEmpty(query.QParentId))
18     {
19         menus = menus.Where(s => s.ParentId == query.QParentId.Trim());
20     }
21     if (query.QMenuType != null)
22     {
23         menus = menus.Where(s => s.MenuType == query.QMenuType);
24     }
25 
26     UpdateDropDownList();
27     return View(new MenuIndexVM { Menus = await menus.ToListAsync(), Query = query });
28 }

视图调整：用户点击删除时，弹出确认框，调用Ajax方式删除数据，不再通过页面跳转；

  1 @using MyWebSite.ViewModels
  2 @addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
  3 
  4 @model MyWebSite.Areas.Configuration.ViewModels.MenuIndexVM
  5 @{
  6     ViewData["Title"] = "菜单列表";
  7 
  8     var breadcrumb = new BreadCrumb("菜单列表", "Version 2.0", new List<NavCrumb>
  9     {
 10         new NavCrumb(name:"菜单管理",url: "/Configuration/Menu"),
 11         new NavCrumb(name:"菜单列表"),
 12     });
 13     ViewBag.BreadCrumb = breadcrumb;
 14 
 15     Layout = "~/Views/Shared/_Layout.cshtml";
 16 }
 17 
 18 <div class="row">
 19     <div class="col-xs-12">
 20         <div class="box with-border">
 21             <form class="form" asp-action="Index">
 22                 <div class="box-header">
 23                     <h3 class="box-title"><i class="fa fa-search margin-r-5">查询条件</i></h3>
 24                     <div class="box-tools pull-right">
 25                         <button type="submit" class="btn btn-success margin-r-5"><i class="fa fa-search margin-r-5"></i>查询</button>
 26                         <a class="btn btn-primary" href="/Configuration/Menu/Create"><i class="fa fa-plus margin-r-5"></i>新建</a>
 27                     </div>
 28                     <div asp-validation-summary="All" class="text-danger"></div>
 29                     <div class="row">
 30                         <div class="col-md-3">
 31                             <div class="form-group">
 32                                 <label asp-for="Query.QName">菜单名称:</label>
 33                                 <input asp-for="Query.QName" class="form-control input-sm">
 34                             </div>
 35                         </div>
 36                         <div class="col-md-3">
 37                             <div class="form-group">
 38                                 <label asp-for="Query.QId">菜单编码:</label>
 39                                 <input asp-for="Query.QId" class="form-control input-sm">
 40                             </div>
 41                         </div>
 42                         <div class="col-md-3">
 43                             <div class="form-group">
 44                                 <label asp-for="Query.QParentId">父级菜单:</label>
 45                                 <select asp-for="Query.QParentId" class="form-control input-sm select2" asp-items="ViewBag.ParentIds">
 46                                     <option value="">-- 请选择 --</option>
 47                                 </select>
 48                             </div>
 49                         </div>
 50                         <div class="col-md-3">
 51                             <div class="form-group">
 52                                 <label asp-for="Query.QMenuType">菜单类型:</label>
 53                                 <select asp-for="Query.QMenuType" class="form-control input-sm select2" asp-items="ViewBag.MenuTypes">
 54                                     <option value="">-- 请选择 --</option>
 55                                 </select>
 56                             </div>
 57                         </div>
 58                     </div>
 59                 </div>
 60             </form>
 61             <div class="box-body">
 62                 <table class="table table-bordered table-hover" style="width: 100%">
 63                     <thead>
 64                         <tr>
 65                             <th>#</th>
 66                             <th>菜单名称</th>
 67                             <th>菜单编号</th>
 68                             <th>父级编号</th>
 69                             <th>组内排序</th>
 70                             <th>菜单类型</th>
 71                             <th>菜单图标</th>
 72                             <th>菜单路径</th>
 73                             <th>操作</th>
 74                         </tr>
 75                     </thead>
 76                     <tbody>
 77                         @{
 78                             var index = 0;
 79                         }
 80                         @foreach (var item in Model.Menus)
 81                         {
 82                             index++;
 83                             <tr>
 84                                 <td>
 85                                     @index.ToString("D3")
 86                                 </td>
 87                                 <td>
 88                                     @Html.ActionLink(@item.Name, "Details", new { id = @item.Id })
 89                                 </td>
 90                                 <td>
 91                                     <span>@item.Id</span>
 92                                 </td>
 93                                 <td>
 94                                     <span>@Html.DisplayFor(modelItem => item.ParentId)</span>
 95                                 </td>
 96                                 <td>
 97                                     <span>@item.IndexCode</span>
 98                                 </td>
 99                                 <td>
100                                     <span>@item.MenuType</span>
101                                 </td>
102                                 <td>
103                                     <i class="fa @item.Icon" data-toggle="tooltip" data-placement="right" title="@item.Icon"></i>
104                                 </td>
105                                 <td>
106                                     <i class="fa fa-ellipsis-h" data-toggle="tooltip" data-placement="top" title="@Html.DisplayFor(modelItem => item.Url)"></i>
107                                 </td>
108                                 <td>
109                                     @Html.ActionLink("编辑", "Edit", new { id = @item.Id })|
110                                     @Html.ActionLink("详情", "Details", new { id = @item.Id })|
111                                     <a href="#" onclick="onDelete('@item.Id', '@item.Name');">删除</a>
112                                 </td>
113                             </tr>
114                         }
115                     </tbody>
116                 </table>
117             </div>
118         </div>
119     </div>
120 </div>
121 
122 @section Scripts{
123     @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
124     <script>
125         function onDelete(id, name) {
126             BootstrapDialog.show({
127                 message: '确认删除菜单-' + name + '[' + id + ']？',
128                 size: BootstrapDialog.SIZE_SMALL,
129                 draggable: true,
130                 buttons: [
131                     {
132                         icon: 'fa fa-check',
133                         label: '确定',
134                         cssClass: 'btn-primary',
135                         action: function (dialogRef) {
136                             dialogRef.close();
137                             $.ajax({
138                                 type: 'POST',
139                                 url: '/Configuration/Menu/Delete',
140                                 data: { id: id },
141                                 success: function () {
142                                     location.reload();
143                                 }
144                             });
145                         }
146                     }, {
147                         icon: 'fa fa-close',
148                         label: '取消',
149                         action: function (dialogRef) {
150                             dialogRef.close();
151                         }
152                     }
153                 ]
154             });
155         }
156     </script>
157 }

新建页改写

控制器调整：这里控制器有2个Create方法，一个是Http Get类型，用户列表页点新建时，跳转到该方法，另外一个是Http Post类型，用户填完新建的菜单信息后，点击保存，跳转到该方法。在Http Post方法中，为了防止页面over post，需要指定绑定的属性Bind("Id,Name,ParentId,IndexCode,Url,MenuType,Icon,Remarks")，当然，也可以用TryUpdateModel()实现，以后再介绍；

 1 /// <summary>
 2 /// 新建空白页面
 3 /// </summary>
 4 /// <returns></returns>
 5 public IActionResult Create()
 6 {
 7     var model = new Menu
 8     {
 9         Id = "MXX_XX_XX",
10         IndexCode = 1,
11         Icon = "fa-circle-o"
12     };
13     UpdateDropDownList();
14     return View(model);
15 }
16 
17 /// <summary>
18 /// 新建保存页面
19 /// </summary>
20 /// <param name="menu"></param>
21 /// <returns></returns>
22 [HttpPost]
23 public async Task<IActionResult> Create([Bind("Id,Name,ParentId,IndexCode,Url,MenuType,Icon,Remarks")] Menu menu)
24 {
25     if (ModelState.IsValid)
26     {
27         if (!MenuExists(menu.Id))
28         {
29             _context.Add(menu);
30             await _context.SaveChangesAsync();
31 
32             _NavMenuService.InitOrUpdate();
33             return RedirectToAction(nameof(Index));
34         }
35         else
36         {
37             ModelState.AddModelError("Id", "菜单编号已存在，请修改菜单编号.");
38         }
39     }
40     UpdateDropDownList(menu);
41     return View(menu);
42 }

视图调整：引入前端数据验证，并增加一些数据控制，比如菜单类型非操作菜单时，菜单路径不可编辑等等；

 1 @using MyWebSite.ViewModels
 2 @using MyWebSite.Areas.Configuration.Models
 3 @model MyWebSite.Areas.Configuration.Models.Menu
 4 
 5 @addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
 6 
 7 @{
 8     ViewData["Title"] = "菜单新建";
 9 
10     var breadcrumb = new BreadCrumb("菜单新建", "Version 2.0", new List<NavCrumb>
11     {
12         new NavCrumb(name:"菜单管理",url: "/Configuration/Menu"),
13         new NavCrumb(name:"菜单新建"),
14     });
15     ViewBag.BreadCrumb = breadcrumb;
16 
17     Layout = "~/Views/Shared/_Layout.cshtml";
18 }
19 <section class="content">
20     <div class="row">
21         <div class="col-md-8">
22             <div class="box">
23                 <div class="box-header with-border">
24                     <h3 class="box-title">新建</h3>
25                 </div>
26                 <form asp-action="Create">
27                     <div asp-validation-summary="All" class="text-danger"></div>
28                     <div class="box-body">
29                         <div class="form-group col-md-6">
30                             <label asp-for="Id">菜单编号</label>
31                             <input asp-for="Id" class="form-control input-sm">
32                         </div>
33                         <div class="form-group  col-md-6">
34                             <label asp-for="Name">菜单名称</label>
35                             <input asp-for="Name" class="form-control input-sm">
36                         </div>
37                         <div class="form-group  col-md-6">
38                             <label asp-for="ParentId">父级菜单</label>
39                             <select asp-for="ParentId" class="form-control input-sm select2" asp-items="ViewBag.ParentIds">
40                                 <option value="">-- 请选择 --</option>
41                             </select>
42                         </div>
43                         <div class="form-group  col-md-6">
44                             <label asp-for="IndexCode">组内排序</label>
45                             <input asp-for="IndexCode" class="form-control input-sm">
46                         </div>
47                         <div class="form-group  col-md-6">
48                             <label asp-for="MenuType">菜单类型</label>
49                             <select asp-for="MenuType" class="form-control input-sm" asp-items="ViewBag.MenuTypes">
50                                 <option value="">-- 请选择 --</option>
51                             </select>
52                         </div>
53                         <div class="form-group  col-md-6">
54                             <label asp-for="Icon">菜单图标</label>
55                             <div class="input-group">
56                                 <span class="input-group-addon"><i id="IconfShow" class="fa @Model.Icon"></i></span>
57                                 <input asp-for="Icon" class="form-control input-sm">
58                             </div>
59                         </div>
60                         <div class="form-group  col-md-6">
61                             <label asp-for="Url">菜单路径</label>
62                             @if (Model.MenuType == MenuTypes.操作菜单)
63                             {
64                                 <input asp-for="Url" class="form-control input-sm">
65                             }
66                             else
67                             {
68                                 <input asp-for="Url" class="form-control input-sm" readonly>
69                             }
70                         </div>
71                         <div class="form-group  col-md-6">
72                             <label asp-for="Remarks">备注</label>
73                             <input asp-for="Remarks" class="form-control input-sm">
74                         </div>
75                     </div>
76                     <div class="box-footer">
77                         <button type="submit" class="btn btn-primary"><i id="IconfShow" class="fa fa-save"></i> 保存</button>
78                         <a asp-action="Index" class="btn btn-default"><i id="IconfShow" class="fa fa-undo"></i> 返回</a>
79                     </div>
80                 </form>
81             </div>
82 
83         </div>
84     </div>
85 </section>
86 @section Scripts {
87     <script src="~/js/Configuration/Menu.js"></script>
88     @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
89 }

详情页改写

控制器调整：不用大的调整，只是增加了下拉框的初始化工作；

 1 /// <summary>
 2 /// 详情页
 3 /// </summary>
 4 /// <param name="id"></param>
 5 /// <returns></returns>
 6 public async Task<IActionResult> Details(string id)
 7 {
 8     if (id == null)
 9     {
10         return NotFound();
11     }
12 
13     var menu = await _context.Menus
14     .SingleOrDefaultAsync(m => m.Id == id);
15     if (menu == null)
16     {
17         return NotFound();
18     }
19 
20     UpdateDropDownList(menu);
21     return View(menu);
22 }

视图调整：跟创建界面大体差不多，只是控制属性字段不允许编辑，也不用数据验证；

@using MyWebSite.ViewModels
@model MyWebSite.Areas.Configuration.Models.Menu

@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers

@{
    ViewData["Title"] = "菜单详情";

    var breadcrumb = new BreadCrumb("菜单详情", "Version 2.0", new List<NavCrumb>
    {
        new NavCrumb(name:"菜单管理",url: "/Configuration/Menu"),
        new NavCrumb(name:"菜单详情"),
        new NavCrumb(name:Model.Id),
    });
    ViewBag.BreadCrumb = breadcrumb;

    Layout = "~/Views/Shared/_Layout.cshtml";
}
<section class="content">
    <div class="row">
        <div class="col-md-8">
            <div class="box">
                <div class="box-header with-border">
                    <h3 class="box-title">详情</h3>
                </div>
                <form>
                    <div class="box-body">
                        <div class="form-group col-md-6">
                            <label asp-for="Id">菜单编号</label>
                            <input asp-for="Id" class="form-control input-sm" readonly>
                        </div>
                        <div class="form-group  col-md-6">
                            <label asp-for="Name">菜单名称</label>
                            <input asp-for="Name" class="form-control input-sm" readonly>
                        </div>
                        <div class="form-group  col-md-6">
                            <label asp-for="ParentId">父级菜单</label>
                            <select asp-for="ParentId" class="form-control input-sm" asp-items="ViewBag.ParentIds" disabled>
                            </select>
                        </div>
                        <div class="form-group  col-md-6">
                            <label asp-for="IndexCode">组内排序</label>
                            <input asp-for="IndexCode" class="form-control input-sm" readonly>
                        </div>
                        <div class="form-group  col-md-6">
                            <label asp-for="MenuType">菜单类型</label>
                            <input asp-for="MenuType" class="form-control input-sm" readonly>
                        </div>
                        <div class="form-group  col-md-6">
                            <label asp-for="Icon">菜单图标</label>
                            <div class="input-group">
                                <span class="input-group-addon"><i id="IconfShow" class="fa @Model.Icon"></i></span>
                                <input asp-for="Icon" class="form-control input-sm" readonly>
                            </div>
                        </div>
                        <div class="form-group  col-md-6">
                            <label asp-for="Url">菜单路径</label>
                            <input asp-for="Url" class="form-control input-sm" readonly>
                        </div>
                        <div class="form-group  col-md-6">
                            <label asp-for="Remarks">备注</label>
                            <input asp-for="Remarks" class="form-control input-sm" readonly>
                        </div>
                    </div>
                    <div class="box-footer">
                        <a asp-action="Edit" asp-route-id="@Model.Id" class="btn btn-primary"><i id="IconfShow" class="fa fa-edit"></i> 编辑</a>
                        <a asp-action="Index" class="btn btn-default"><i id="IconfShow" class="fa fa-undo"></i> 返回</a>
                    </div>
                </form>
            </div>

        </div>
    </div>
</section>

编辑页面改写

控制器调整：也是有Http Get和Http Post方法，分别是开始编辑和编辑保存跳转的方法，同时加上防止over post字段绑定；

 1 /// <summary>
 2 /// 开始编辑
 3 /// </summary>
 4 /// <param name="id"></param>
 5 /// <returns></returns>
 6 public async Task<IActionResult> Edit(string id)
 7 {
 8     if (id == null)
 9     {
10         return NotFound();
11     }
12 
13     var menu = await _context.Menus.SingleOrDefaultAsync(m => m.Id == id);
14     if (menu == null)
15     {
16         return NotFound();
17     }
18 
19     UpdateDropDownList(menu);
20     return View(menu);
21 }
22 
23 /// <summary>
24 /// 编辑保存
25 /// </summary>
26 /// <param name="id"></param>
27 /// <param name="menu"></param>
28 /// <returns></returns>
29 [HttpPost]
30 public async Task<IActionResult> Edit(string id, [Bind("Id,Name,ParentId,IndexCode,Url,MenuType,Icon,Remarks")] Menu menu)
31 {
32     if (id != menu.Id)
33     {
34         return NotFound();
35     }
36 
37     if (ModelState.IsValid)
38     {
39         try
40         {
41             _context.Update(menu);
42             await _context.SaveChangesAsync();
43         }
44         catch (DbUpdateConcurrencyException)
45         {
46             if (!MenuExists(menu.Id))
47             {
48                 return NotFound();
49             }
50             else
51             {
52                 throw;
53             }
54         }
55         _NavMenuService.InitOrUpdate();
56         return RedirectToAction(nameof(Index));
57     }
58 
59     UpdateDropDownList(menu);
60     return View(menu);
61 }

视图调整：跟创建界面大体差不多，需要数据验证和数据控制；

 1 @using MyWebSite.ViewModels
 2 @using MyWebSite.Areas.Configuration.Models
 3 @model MyWebSite.Areas.Configuration.Models.Menu
 4 
 5 @addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
 6 
 7 @{
 8     ViewData["Title"] = "菜单编辑";
 9 
10     var breadcrumb = new BreadCrumb("菜单编辑", "Version 2.0", new List<NavCrumb>
11     {
12         new NavCrumb(name:"菜单管理",url: "/Configuration/Menu"),
13         new NavCrumb(name:"菜单编辑"),
14         new NavCrumb(name:Model.Id),
15     });
16     ViewBag.BreadCrumb = breadcrumb;
17 
18     Layout = "~/Views/Shared/_Layout.cshtml";
19 }
20 <section class="content">
21     <div class="row">
22         <div class="col-md-8">
23             <div class="box">
24                 <div class="box-header with-border">
25                     <h3 class="box-title">编辑</h3>
26                 </div>
27                 <form asp-action="Edit">
28                     <div asp-validation-summary="All" class="text-danger"></div>
29                     <div class="box-body">
30                         <div class="form-group col-md-6">
31                             <label asp-for="Id">菜单编号</label>
32                             <input asp-for="Id" class="form-control input-sm" readonly>
33                         </div>
34                         <div class="form-group  col-md-6">
35                             <label asp-for="Name">菜单名称</label>
36                             <input asp-for="Name" class="form-control input-sm">
37                         </div>
38                         <div class="form-group  col-md-6">
39                             <label asp-for="ParentId">父级菜单</label>
40                             <select asp-for="ParentId" class="form-control input-sm select2" asp-items="ViewBag.ParentIds">
41                                 <option value="">-- 请选择 --</option>
42                             </select>
43                         </div>
44                         <div class="form-group  col-md-6">
45                             <label asp-for="IndexCode">组内排序</label>
46                             <input asp-for="IndexCode" class="form-control input-sm">
47                         </div>
48                         <div class="form-group  col-md-6">
49                             <label asp-for="MenuType">菜单类型</label>
50                             <select asp-for="MenuType" class="form-control input-sm" asp-items="ViewBag.MenuTypes">
51                                 <option value="">-- 请选择 --</option>
52                             </select>
53                         </div>
54                         <div class="form-group  col-md-6">
55                             <label asp-for="Icon">菜单图标</label>
56                             <div class="input-group">
57                                 <span class="input-group-addon"><i id="IconfShow" class="fa @Model.Icon"></i></span>
58                                 <input asp-for="Icon" class="form-control input-sm">
59                             </div>
60                         </div>
61                         <div class="form-group  col-md-6">
62                             <label asp-for="Url">菜单路径</label>
63                             @if (Model.MenuType == MenuTypes.操作菜单)
64                             {
65                                 <input asp-for="Url" class="form-control input-sm">
66                             }
67                             else
68                             {
69                                 <input asp-for="Url" class="form-control input-sm" readonly>
70                             }
71                         </div>
72                         <div class="form-group  col-md-6">
73                             <label asp-for="Remarks">备注</label>
74                             <input asp-for="Remarks" class="form-control input-sm">
75                         </div>
76                     </div>
77                     <div class="box-footer">
78                         <button type="submit" class="btn btn-primary"><i id="IconfShow" class="fa fa-save"></i> 保存</button>
79                         <a asp-action="Index" class="btn btn-default"><i id="IconfShow" class="fa fa-undo"></i> 返回</a>
80                     </div>
81                 </form>
82             </div>
83 
84         </div>
85     </div>
86 </section>
87 @section Scripts {
88     <script src="~/js/Configuration/Menu.js" ></script>
89     @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
90 }

以上，我们可以通过增删改查界面操作菜单项了，但是要怎么将数据库中的菜单跟左侧的导航菜单关联呢？下节，我们将实现下这个功能。

动态加载导航菜单

前面章节说过，物理数据库菜单Menu是表格结构，而界面上的导航菜单是树状结构，那应该怎么处理呢？我们考虑先定义树状导航菜单的数据结构，然后表格结构的菜单项通过逻辑处理，转换成树状的导航菜单，就可以满足我们的要求了。

第一步，定义导航菜单：属性跟菜单项差不多，不同的是没有父菜单，而是子菜单列表，这样可以包含子菜单，实现菜单的树状嵌套；

 1 /// <summary>
 2 /// 导航菜单项
 3 /// </summary>
 4 public class NavMenu
 5 {
 6     public string Id { get; set; }
 7     public string Name { get; set; }
 8     public MenuTypes MenuType { get; set; }
 9     public string Url { get; set; }
10     public string Icon { get; set; }
11     public bool IsOpen { get; set; }
12 
13     /// <summary>
14     /// 子菜单
15     /// </summary>
16     public IList<NavMenu> SubNavMenus = new List<NavMenu>();
17 }
18 
19 /// <summary>
20 /// 左侧导航菜单视图模型
21 /// </summary>
22 public class NavMenuVM
23 {
24     public IList<NavMenu> NavMenus { get; set; }
25 
26     public string[] MenuidsOpen { get; set; }
27 }

第二步，实现获取数据库保存的所有菜单项信息服务NavMenuService：将表格结构的菜单项，转换成树状的导航菜单；

 1 /// <summary>
 2 /// 菜单服务
 3 /// </summary>
 4 public class NavMenuService : INavMenuService
 5 {
 6     private readonly ApplicationDbContext _context;
 7     public NavMenuService(ApplicationDbContext context)
 8     {
 9         _context = context;
10     }
11 
12     private static IList<NavMenu> NavMenus { get; set; }
13 
14     /// <summary>
15     /// 获取导航菜单
16     /// </summary>
17     /// <returns></returns>
18     public IList<NavMenu> GetNavMenus()
19     {
20         if (NavMenus == null)
21             InitOrUpdate();
22 
23         return NavMenus;
24     }
25     /// <summary>
26     /// 生成导航菜单
27     /// </summary>
28     /// <returns></returns>
29     public void InitOrUpdate()
30     {
31         NavMenus = new List<NavMenu>();
32 
33         var rootMenus = _context.Menus
34             .Where(s => string.IsNullOrEmpty(s.ParentId))
35             .AsNoTracking()
36             .OrderBy(s => s.IndexCode)
37             .ToList();
38 
39         foreach (var rootMenu in rootMenus)
40         {
41             NavMenus.Add(GetOneNavMenu(rootMenu));
42         }
43     }
44     /// <summary>
45     /// 根据给定的Menu，生成对应的导航菜单
46     /// </summary>
47     /// <param name="menu"></param>
48     /// <returns></returns>
49     public NavMenu GetOneNavMenu(Menu menu)
50     {
51         //构建菜单项
52         var navMenu = new NavMenu
53         {
54             Id = menu.Id,
55             Name = menu.Name,
56             MenuType = menu.MenuType.Value,
57             Url = menu.Url,
58             Icon = menu.Icon
59         };
60 
61         //构建子菜单
62         var subMenus = _context.Menus
63             .Where(s => s.ParentId == menu.Id)
64             .AsNoTracking()
65             .OrderBy(s => s.IndexCode)
66             .ToList();
67 
68         foreach (var subMenu in subMenus)
69         {
70             navMenu.SubNavMenus.Add(GetOneNavMenu(subMenu));
71         }
72 
73         return navMenu;
74     }

第三步，我们需要定义一个部分视图_NavMenu，具体规定菜单的显示样式，重要的是，如果包含子菜单的时候，子菜单仍然使用_NavMenu递归渲染显示，这样理论上可以支持无穷级别的导航菜单的显示。如果菜单是导航菜单，增加展开样式，并渲染子菜单，如果是操作菜单，定义href为菜单路径；

 1 @using MyWebSite.Areas.Configuration.Models
 2 @using MyWebSite.Areas.Configuration.ViewModels
 3 @model MyWebSite.Areas.Configuration.ViewModels.NavMenuVM
 4 
 5 
 6 @foreach (var navMenu in Model.NavMenus)
 7 {
 8     if (navMenu.MenuType == MenuTypes.导航菜单)
 9     {
10         <li menuid="@navMenu.Id" class="treeview @(Model.MenuidsOpen.Contains(navMenu.Id) ? "menu-open" : "")">
11             <a href="#">
12                 <i class="fa @navMenu.Icon"></i> <span>@navMenu.Name</span>
13                 <span class="pull-right-container">
14                     <i class="fa fa-angle-left pull-right"></i>
15                 </span>
16             </a>
17             <ul class="treeview-menu" @(Model.MenuidsOpen.Contains(navMenu.Id) ? @"style=display:block;" : "")>
18                 @await Html.PartialAsync("_NavMenu", new NavMenuVM
19            {
20                NavMenus = navMenu.SubNavMenus,
21                MenuidsOpen = Model.MenuidsOpen
22            })
23             </ul>
24         </li>
25     }
26     else if ((navMenu.MenuType == MenuTypes.操作菜单))
27     {
28         <li menuid="@navMenu.Id">
29             <a href="@navMenu.Url" @(navMenu.Url != null && navMenu.Url.StartsWith("http") ? @"target=_blank" : "")>
30                 <i class="fa @navMenu.Icon"></i><span>@navMenu.Name</span>
31             </a>
32         </li>
33     }
34 }

最后，我们渲染下整个导航视图，我们已经有了NavMenuService服务，那怎么在UI界面去访问和使用它呢？其实.Net Core里提供了很方便的机制去访问，直接在Razor视图里将服务注册就行了，如：@inject INavMenuService NavMenuServiceIns

 1 @using Microsoft.AspNetCore.Http
 2 @using MyWebSite.Areas.Configuration.ViewModels
 3 @using MyWebSite.Services.Interfaces
 4 @model MyWebSite.Models.ApplicationUser
 5 
 6 @inject IHttpContextAccessor  HttpContextAccessorIns
 7 @inject INavMenuService NavMenuServiceIns
 8 
 9 <aside class="main-sidebar">
10     <section class="sidebar">
11         <div class="user-panel">
12             <div class="pull-left image">
13                 <img src="~/lib/AdminLTE/dist/img/user2-160x160.jpg" class="img-circle" alt="User Image">
14             </div>
15             <div class="pull-left info">
16                 <p>@Model.NickName</p>
17                 <a href="#"><i class="fa fa-circle text-success"></i> 在线</a>
18             </div>
19         </div>
20         <form action="#" method="get" class="sidebar-form">
21             <div class="input-group">
22                 <input type="text" name="q" class="form-control" placeholder="Search...">
23                 <span class="input-group-btn">
24                     <button type="submit" name="search" id="search-btn" class="btn btn-flat">
25                         <i class="fa fa-search"></i>
26                     </button>
27                 </span>
28             </div>
29         </form>
30         <ul class="sidebar-menu" data-widget="tree">
31             <li class="header">菜单导航</li>
32             @{
33                 var navMenus = NavMenuServiceIns.GetNavMenus();
34                 var cookieMenuidsOpen = HttpContextAccessorIns.HttpContext.Request.Cookies["menuids_open"] ?? "";
35             }
36             @await Html.PartialAsync("_NavMenu", new NavMenuVM
37        {
38            NavMenus = navMenus,
39            MenuidsOpen = cookieMenuidsOpen == null ? new string[] { } : cookieMenuidsOpen.Split(",")
40        })
41 
42             <li><a href="https://adminlte.io/docs"><i class="fa fa-book"></i> <span>Documentation</span></a></li>
43             <li class="header">LABELS</li>
44             <li><a href="#"><i class="fa fa-circle-o text-red"></i> <span>Important</span></a></li>
45             <li><a href="#"><i class="fa fa-circle-o text-yellow"></i> <span>Warning</span></a></li>
46             <li><a href="#"><i class="fa fa-circle-o text-aqua"></i> <span>Information</span></a></li>
47         </ul>
48     </section>
49 </aside>

导航菜单刷新优化

现在我们的导航菜单的展示功能基本完成了，但是这里有个小小的用户体验的问题，就是每次点击导航菜单项时，由于页面跳转，导致整个Layout页面会刷新，那左侧的导航菜单也会刷新，这样之前展开的菜单就会折叠起来：

要保持原有的菜单不被折叠，有很多方法，比如不使用Layout，点击导航菜单项时，通过Ajax局部刷新右侧内容区域，或者直接做成单页模式的网站，保证左侧的导航菜单不因不同内容而刷新。这里考虑.Net Core使用Layout的便捷性，思路如下：点击导航菜单项时，保存展开的菜单项id到cookie中，跳转下一个界面以后，根据cookie中的菜单项id，重新设置展开状态

 1 $('.main-sidebar a').click(function () {
 2     //记录菜单展开状态
 3     var href = $(this).attr('href')
 4     if (href === null || href === "#") return
 5     var menuids = [];
 6     $('.menu-open').each(function () {
 7         menuids.push($(this).attr('menuid'))
 8     })
 9     $.cookie('menuids_open', menuids.join(','), { path: "/" })
10 })