Manage user roles in asp.net core identity

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In this video we will discuss user role membership i.e how to add or remove roles for a given user using the asp.net core identity api. This is very similar to Part 81 where we discussed how to add or remove users from a given role.


On Edit user view, when "Manage Roles" button is clicked, we want to redirect to ManageUserRoles view.

<div class="card-footer">

    <a asp-action="ManageUserRoles" asp-route-userId="@Model.Id"

       class="btn btn-primary">

        Manage Roles

    </a>

</div>

ManageUserRoles view is as shown below. If you want the role to be assigned to the given user, check the checkbox, otherwise leave it unchecked. 



Once the Update button is clicked the data should be updated in the underlying AspNetUserRoles database table. 

UserRolesViewModel Class

public class UserRolesViewModel

{

    public string RoleId { get; set; }

    public string RoleName { get; set; }

    public bool IsSelected { get; set; }

}

• In the UserRolesViewModel class, in addition to RoleId property, we have RoleName and IsSelected properties. 
• RoleName property is required so we can display the RoleName on the view. 
• IsSelected property is required to determine if the role is selected to be assigned to the given user.
• We could include UserId property also in the UserRolesViewModel class, but as far as this view is concerned, there is a one-to-many relationship from User to Roles. So, in order not to repeat UserId for each Role, we will use ViewBag to pass UserId from controller to the view.

HttpGet ManageUserRoles Action

[HttpGet]

public async Task<IActionResult> ManageUserRoles(string userId)

{

    ViewBag.userId = userId;

    var user = await userManager.FindByIdAsync(userId);

    if (user == null)

    {

        ViewBag.ErrorMessage = $"User with Id = {userId} cannot be found";

        return View("NotFound");

    }

    var model = new List<UserRolesViewModel>();

    foreach (var role in roleManager.Roles)

    {

        var userRolesViewModel = new UserRolesViewModel

        {

            RoleId = role.Id,

            RoleName = role.Name

        };

        if (await userManager.IsInRoleAsync(user, role.Name))

        {

            userRolesViewModel.IsSelected = true;

        }

        else

        {

            userRolesViewModel.IsSelected = false;

        }

        model.Add(userRolesViewModel);

    }

    return View(model);

}

HttpPost ManageUserRoles Action

[HttpPost]

public async Task<IActionResult>

    ManageUserRoles(List<UserRolesViewModel> model, string userId)

{

    var user = await userManager.FindByIdAsync(userId);

    if (user == null)

    {

        ViewBag.ErrorMessage = $"User with Id = {userId} cannot be found";

        return View("NotFound");

    }

    var roles = await userManager.GetRolesAsync(user);

    var result = await userManager.RemoveFromRolesAsync(user, roles);

    if (!result.Succeeded)

    {

        ModelState.AddModelError("", "Cannot remove user existing roles");

        return View(model);

    }

    result = await userManager.AddToRolesAsync(user,

        model.Where(x => x.IsSelected).Select(y => y.RoleName));

    if (!result.Succeeded)

    {

        ModelState.AddModelError("", "Cannot add selected roles to user");

        return View(model);

    }

    return RedirectToAction("EditUser", new { Id = userId });

}

ManageUserRoles View

@model List<UserRolesViewModel>

@{

    var userId = ViewBag.userId;

}

<form method="post">

    <div class="card">

        <div class="card-header">

            <h2>Manage User Roles</h2>

        </div>

        <div class="card-body">

            @for (int i = 0; i < Model.Count; i++)

            {

                <div class="form-check m-1">

                    <input type="hidden" asp-for="@Model[i].RoleId" />

                    <input type="hidden" asp-for="@Model[i].RoleName" />

                    <input asp-for="@Model[i].IsSelected" class="form-check-input" />

                    <label class="form-check-label" asp-for="@Model[i].IsSelected">

                        @Model[i].RoleName

                    </label>

                </div>

            }

            <div asp-validation-summary="All" class="text-danger"></div>

        </div>

        <div class="card-footer">

            <input type="submit" value="Update" class="btn btn-primary"

                   style="width:auto" />

            <a asp-action="EditUser" asp-route-id="@userId"

               class="btn btn-primary" style="width:auto">Cancel</a>

        </div>

    </div>

</form>