Role Manager

• 创建，删除 Role
• 把用户添加到 Role
• 对 Role 进行授权 [Authorize(Roles = "xxxRle")]

要启用默认的 IdentityRole，在 Startup 里面配置时就不能使用 AddDefaultIdentity 了。需要使用 AddIdentity 并指定 User 和 Role：

services.AddIdentity<ApplicationUser, IdentityRole>(options =>
        {
            options.Password.RequireNonAlphanumeric = false;
            ...
        })
    .AddDefaultUI(UIFramework.Bootstrap4)
    .AddEntityFrameworkStores<ApplicationDbContext>();

Role Controller

通过注入的 UserManager 和 RoleManager 操作角色。

单独操作 Role 的代码和 UserController 相似，主要不同在于修改 User 的 Role：

[Authorize]
public class RoleController : Controller
{
    private readonly UserManager<ApplicationUser> _userManager;
    private readonly RoleManager<IdentityRole> _roleManager;
    public RoleController(
        UserManager<ApplicationUser> userManager,
        RoleManager<IdentityRole> roleManager)
    {
        _userManager = userManager;
        _roleManager = roleManager;
    }
    public async Task<IActionResult> Index()
    {
        var roles = await _roleManager.Roles.ToListAsync();
        return View(roles);
    }
    public IActionResult AddRole()
    {
        return View();
    }
    [HttpPost]
    public async Task<IActionResult> AddRole(RoleAddViewModel roleAddViewModel)
    {
        if (!ModelState.IsValid)
        {
            return View(roleAddViewModel);
        }
        var role = new IdentityRole { Name = roleAddViewModel.RoleName };
        var result=await _roleManager.CreateAsync(role);
        if (result.Succeeded)
        {
            return RedirectToAction("Index");
        }
        foreach (var error in result.Errors)
        {
            ModelState.AddModelError(string.Empty, error.Description);
        }
        return View(roleAddViewModel);
    }
    public async Task<IActionResult> EditRole(string id)
    {
        var role=await _roleManager.FindByIdAsync(id);
        if (role == null)
        {
            return RedirectToAction("Index");
        }
        var roleEditViewModel = new RoleEditViewModel
        {
            Id = id,
            RoleName = role.Name,
            Users = new List<string>()
        };
        var users=await _userManager.Users.ToListAsync();
        foreach (var user in users)
        {
            if (await _userManager.IsInRoleAsync(user, role.Name))
            {
                roleEditViewModel.Users.Add(user.UserName);
            }
        }
        return View(roleEditViewModel);
    }
    [HttpPost]
    public async Task<IActionResult> EditRole(RoleEditViewModel roleEditViewModel)
    {
        var role = await _roleManager.FindByIdAsync(roleEditViewModel.Id);
        if (role != null)
        {
            role.Name = roleEditViewModel.RoleName;
            var result = await _roleManager.UpdateAsync(role);
            if (result.Succeeded)
            {
                return RedirectToAction("Index");
            }
            ModelState.AddModelError(string.Empty, "更新角色时出错");
            return View(roleEditViewModel);
        }
        return RedirectToAction("Index");
    }
    [HttpPost]
    public async Task<IActionResult> DeleteRole(string id)
    {
        var role = await _roleManager.FindByIdAsync(id);
        if (role != null)
        {
            var result = await _roleManager.DeleteAsync(role);
            if (result.Succeeded)
            {
                return RedirectToAction("Index");
            }
            ModelState.AddModelError(string.Empty, "删除角色时出错");
        }
        ModelState.AddModelError(string.Empty, "没找到该角色");
        return View("Index", await _roleManager.Roles.ToListAsync());
    }
    public async Task<IActionResult> AddUserToRole(string roleId)
    {
        var role = await _roleManager.FindByIdAsync(roleId);
        if (role == null)
        {
            return RedirectToAction("Index");
        }
        var vm = new UserRoleViewModel
        {
            RoleId = role.Id
        };
        var users = await _userManager.Users.ToListAsync();
        foreach (var user in users)
        {
            if (!await _userManager.IsInRoleAsync(user, role.Name))
            {
                // 筛选出候选用户
                vm.Users.Add(user);
            }
        }
        return View(vm);
    }
    [HttpPost]
    public async Task<IActionResult> AddUserToRole(UserRoleViewModel userRoleViewModel)
    {
        var user = await _userManager.FindByIdAsync(userRoleViewModel.UserId);
        var role = await _roleManager.FindByIdAsync(userRoleViewModel.RoleId);
        if (user != null && role != null)
        {
            var result = await _userManager.AddToRoleAsync(user, role.Name);
            if (result.Succeeded)
            {
                return RedirectToAction("EditRole", new { id = role.Id });
            }
            foreach (var error in result.Errors)
            {
                ModelState.AddModelError(string.Empty, error.Description);
            }
            return View(userRoleViewModel);
        }
        ModelState.AddModelError(string.Empty, "用户或角色未找到");
        return View(userRoleViewModel);
    }
    public async Task<IActionResult> DeleteUserFromRole(string roleId)
    {
        var role = await _roleManager.FindByIdAsync(roleId);
        if (role == null)
        {
            return RedirectToAction("Index");
        }
        var vm = new UserRoleViewModel
        {
            RoleId = role.Id
        };
        var users = await _userManager.Users.ToListAsync();
        foreach (var user in users)
        {
            if (await _userManager.IsInRoleAsync(user, role.Name))
            {
                vm.Users.Add(user);
            }
        }
        return View(vm);
    }
    [HttpPost]
    public async Task<IActionResult> DeleteUserFromRole(UserRoleViewModel userRoleViewModel)
    {
        var user = await _userManager.FindByIdAsync(userRoleViewModel.UserId);
        var role = await _roleManager.FindByIdAsync(userRoleViewModel.RoleId);
        if (user != null && role != null)
        {
            if (await _userManager.IsInRoleAsync(user, role.Name))
            {
                var result = await _userManager.RemoveFromRoleAsync(user, role.Name);
                if (result.Succeeded)
                {
                    return RedirectToAction("EditRole", new { id = role.Id });
                }
                foreach (var error in result.Errors)
                {
                    ModelState.AddModelError(string.Empty, error.Description);
                }
                return View(userRoleViewModel);
            }
            ModelState.AddModelError(string.Empty, "用户不在角色里");
            return View(userRoleViewModel);
        }
        ModelState.AddModelError(string.Empty, "用户或角色未找到");
        return View(userRoleViewModel);
    }
}