昨天角色的CRUD 功能都完成了，接着就是要把角色分配给用户了，先建立一个ViewModel CustomUserRoleViewModel，这是用来呈现角色底下用户的ViewModel。
namespace BlazorServer.ViewModels;
public class CustomUserRoleViewModel
{
public string? UserId { get; set; }
public string? UserName { get; set; }
public bool IsSelected { get; set; }
}
再于IRolesRepository跟RolesRepository加上编辑角色内用户的功能，这里用了多载，第一个相当于Get 取得页面初始数据，第二个则是Post 提交修改后的数据。
IRolesRepository.cs
…
Task<List<CustomUserRoleViewModel>> EditUsersInRoleAsync(string roleId);
Task<ResultViewModel> EditUsersInRoleAsync(List<CustomUserRoleViewModel> model, string roleId);
RolesRepository.cs
…
public async Task<List<CustomUserRoleViewModel>> EditUsersInRoleAsync(string roleId)
{
var role = await _roleManager.FindByIdAsync(roleId);
var model = new List<CustomUserRoleViewModel>();
// 这里注意，_userManager.Users.ToList()后面一定要加.ToList()，否则会抛出异常：https://stackoverflow.com/questions/60727080/helping-solving-there-is-already-an-open-datareader-associated-with-this-comman
foreach (var user in _userManager.Users.ToList())
{
var userRoleViewModel = new CustomUserRoleViewModel
{
UserId = user.Id,
UserName = user.UserName
};
if (await _userManager.IsInRoleAsync(user, role.Name))
userRoleViewModel.IsSelected = true;
else
userRoleViewModel.IsSelected = false;
model.Add(userRoleViewModel);
}
return model;
}
public async Task<ResultViewModel> EditUsersInRoleAsync(List<CustomUserRoleViewModel> model, string roleId)
{
var role = await _roleManager.FindByIdAsync(roleId);
foreach (var m in model)
{
var user = await _userManager.FindByIdAsync(m.UserId);
IdentityResult result;
if (m.IsSelected && !await _userManager.IsInRoleAsync(user, role.Name))
result = await _userManager.AddToRoleAsync(user, role.Name);
else if (!m.IsSelected && await _userManager.IsInRoleAsync(user, role.Name))
result = await _userManager.RemoveFromRoleAsync(user, role.Name);
else
continue;
if (result.Succeeded)
{
if (model.Count > 0)
continue;
return new ResultViewModel
{
Message = roleId,
IsSuccess = true
};
}
return new ResultViewModel
{
Message = roleId,
IsSuccess = false
};
}
return new ResultViewModel
{
Message = roleId,
IsSuccess = true
};
}
接着加上页面。
EditUsersInRole.razor.cs
using BlazorServer.Repository;
using BlazorServer.Shared;
using BlazorServer.ViewModels;
using Microsoft.AspNetCore.Components;
using Microsoft.JSInterop;
namespace BlazorServer.Pages.RolesManagement;
public partial class EditUsersInRole
{
[Inject] protected IRolesRepository? RolesRepository { get; set; }
[Inject] protected NavigationManager? NavigationManager { get; set; }
[Inject] protected IJSRuntime? Js { get; set; }
private JsInteropClasses? _jsClass;
[Parameter] public string? Id { get; set; }
public List<CustomUserRoleViewModel> UserRoleViewModel { get; set; } = new List<CustomUserRoleViewModel>();
protected override async Task OnInitializedAsync()
{
await LoadData();
_jsClass = new JsInteropClasses(Js!);
}
private async Task LoadData()
{
UserRoleViewModel = (await RolesRepository!.EditUsersInRoleAsync(Id!)).ToList();
}
public async Task HandleValidSubmit()
{
var result = await RolesRepository!.EditUsersInRoleAsync(UserRoleViewModel, Id!);
if (result.IsSuccess)
{
NavigationManager!.NavigateTo($"/RolesManagement/EditRole/{Id}");
}
else
{
await _jsClass!.Alert(result.Message!);
}
}
public void Cancel()
{
NavigationManager!.NavigateTo($"/RolesManagement/EditRole/{Id}");
}
}
EditUsersInRole.razor
@page "/RolesManagement/EditUsersInRole/{Id}"
@attribute [Authorize]
<EditForm Model="UserRoleViewModel" OnValidSubmit="HandleValidSubmit">
<DataAnnotationsValidator />
<ValidationSummary />
<div class="card">
<div class="card-header">
<h2>从角色新增或者删除用户</h2>
</div>
<div class="card-body">
@foreach (var user in UserRoleViewModel)
{
<div class="form-check m-1">
<label class="form-check-label">
<InputCheckbox @bind-Value="@user.IsSelected"></InputCheckbox>
@user.UserName
</label>
</div>
}
</div>
<div class="card-footer">
<button type="submit" class="btn btn-primary">更新</button>
<button type="button" class="btn btn-danger" @onclick="@Cancel">取消</button>
</div>
</div>
</EditForm>
EditRole.razor.cs新增一个方法，跳转EditUsersInRole.razor，可以编辑角色底下用户。
public void EditUsersInRole()
{
NavigationManager!.NavigateTo($"/RolesManagement/EditUsersInRole/{Id}");
}
EditRole.razor加上一个按钮调用该方法。
<button type="button" class="btn btn-info" @onclick="EditUsersInRole">新增或移除该角色底下的用户</button>
启动网页进入编辑角色用户页面，可以看到目前只有一个用户，将Admin角色分配给这个用户，如此一来就完成了Admin跟test@gmail.com的分配，不过要测试是否成功的话，需要对页面加入限制，还要新增一个用户测试。
先将每个razor component 的@attribute [Authorize]改成@attribute [Authorize(Roles = "Admin")]，表示要看到这页面的人必须有Role Admin。
再去NavMenu.razor，于原本的<AuthorizeView>上方加入下面这段代码，同理要看到跳转Roles链接的人必须有Role Admin，再把原本<AuthorizeView>的Roles链接删除。
<AuthorizeView Roles="Admin">
<Authorized>
<li class="nav-item px-3">
<NavLink class="nav-link" href="RolesManagement/RolesList" Match="NavLinkMatch.All">
<span class="bi bi-kanban-fill h4 p-2 mb-0" aria-hidden="true"></span> Roles
</NavLink>
</li>
</Authorized>
</AuthorizeView>
最后新增一名用户，名为user@gmail.com，以此用户登录，会发现左边的Roles不见了，手动输入网址也会提示没有权限，这就是最基本的角色(Role)授权，如果系统很简单只要用角色划分权限，这样就能满足需求了。
引用：
注：本文代码通过 .NET 6 + Visual Studio 2022重构，可点击原文链接与重构后代码比较学习，谢谢阅读，支持原作者
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