【ASP.NET Identity系列教程（二）】运用ASP.NET Identity - r01cn(11)_H5之家

Custom HTML helper methods are defined as extensions on the HtmlHelper class. My helper, which is called GetUsername, takes a string argument containing a user ID, obtains an instance of the AppUserManager through the GetOwinContext.GetUserManager method (where GetOwinContext is an extension method on the HttpContext class), and uses the FindByIdAsync method to locate the AppUser instance associated with the ID and to return the value of the UserName property.
这个自定义的HTML辅助器方法，是作为HtmlHelper类的扩展进行定义的。该辅助器的名称为GetUsername，以一个含有用户ID的字符串为参数，通过GetOwinContext.GetUserManager方法获取AppUserManager的一个实例（其中GetOwinContext是HttpContext类的扩展方法），并使用FindByIdAsync方法定位与ID相关联的AppUser实例，然后返回UserName属性的值。

Listing 14-11 shows the contents of the Index.cshtml file from the Views/RoleAdmin folder, which I created by right-clicking the Index action method in the code editor and selecting Add View from the pop-up menu.
清单14-11显示了Views/RoleAdmin文件夹中Index.cshtml文件的内容，这是通过在代码编辑器中右击Index动作，并从弹出菜单中选择“Add View（添加视图）”来创建的。

Listing 14-11. The Contents of the Index.cshtml File in the Views/RoleAdmin Folder
清单14-11. Views/RoleAdmin文件夹中Index.cshtml文件的内容

@using Users.Models @using Users.Infrastructure @model IEnumerable<AppRole> @{ ViewBag.Title = "Roles"; }
<div> <div>Roles</div> <table>
<tr><th>ID</th><th>Name</th><th>Users</th><th></th></tr> @if (Model.Count() == 0) { <tr><td colspan="4">No Roles</td></tr> } else { foreach (AppRole role in Model) { <tr> <td>@role.Id</td> <td>@role.Name</td> <td> @if (role.Users == null || role.Users.Count == 0) { @: No Users in Role } else { <p>@string.Join(", ", role.Users.Select(x => Html.GetUserName(x.UserId)))</p> } </td> <td> @using (Html.BeginForm("Delete", "RoleAdmin", new { id = role.Id })) { @Html.ActionLink("Edit", "Edit", new { id = role.Id }, new { @class = "btn btn-primary btn-xs" }) <button type="submit"> Delete </button> } </td> </tr> } } </table> </div> @Html.ActionLink("Create", "Create", null, new { @class = "btn btn-primary" })

This view displays a list of the roles defined by the application, along with the users who are members, and I use the GetUserName helper method to get the name for each user.
该视图显示了一个由应用程序定义的角色列表，且带有成员用户，我用GetUserName辅助器方法获取了每个用户的用户名。

Listing 14-12 shows the Views/RoleAdmin/Create.cshtml file, which I created to allow new roles to be created.
清单14-12显示了Views/RoleAdmin/Create.cshtml文件，这是用来创建新角色的视图。

Listing 14-12. The Contents of the Create.cshtml File in the Views/RoleAdmin Folder
清单14-12. Views/RoleAdmin文件夹中Create.cshtml文件的内容

@model string @{ ViewBag.Title = "Create Role";} <h2>Create Role</h2> @Html.ValidationSummary(false) @using (Html.BeginForm()) { <div> <label>Name</label> <input value="@Model" /> </div> <button type="submit">Create</button> @Html.ActionLink("Cancel", "Index", null, new { @class = "btn btn-default" }) }

The only information required to create a new view is a name, which I gather using a standard input element and submit the value to the Create action method.
创建该视图需要的唯一信息是角色名，我用标准的input元素进行采集，并将该值递交给Create动作方法。

14.3.4 Testing Creating and Deleting Roles
14.3.4 测试角色的创建和删除

To test the new controller, start the application and navigate to the /RoleAdmin/Index URL. To create a new role, click the Create button, enter a name in the input element, and click the second Create button. The new view will be saved to the database and displayed when the browser is redirected to the Index action, as shown in Figure 14-4. You can remove the role from the application by clicking the Delete button.
为了测试新的控制器，启动应用程序并导航到/RoleAdmin/Index URL。为了创建一个新的角色，点击“Create”按钮，在input元素中输入一个角色名，然后点击第二个“Create”按钮。新角色将被保存到数据库，并在浏览器被重定向到Index动作时显示出来，如图14-4所示。可以点击“Delete”按钮将该角色从应用程序中删除。

图14-4

Figure 14-4. Creating a new role
图14-4. 创建新角色

14.3.5 Managing Role Memberships
14.3.5 管理角色成员