ASP.NET MVC: Add User to Role

Step 1: Open AccountController, then add code as below

[Authorize]
public class AccountController : Controller
{
    private ApplicationRoleManager _roleManager;

    public AccountController()
    {
    }

    public AccountController(ApplicationUserManager userManager, ApplicationSignInManager signInManager, ApplicationRoleManager roleManager)
    {
        UserManager = userManager;
        SignInManager = signInManager;
        RoleManager = roleManager;
    }

    public ApplicationRoleManager RoleManager
    {
        get
        {
            return _roleManager ?? HttpContext.GetOwinContext().Get<ApplicationRoleManager>();
        }
        private set
        {
            _roleManager = value;
        }
    }
}

Change Register action as below

//
// GET: /Account/Register
[AllowAnonymous]
public ActionResult Register()
{
    List<SelectListItem> list = new List<SelectListItem>();
    foreach (var role in RoleManager.Roles)
        list.Add(new SelectListItem() { Value = role.Name, Text = role.Name });
    ViewBag.Roles = list;
    return View();
}

//
// POST: /Account/Register
[HttpPost]
[AllowAnonymous]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Register(RegisterViewModel model)
{
    if (ModelState.IsValid)
    {
        var user = new ApplicationUser { UserName = model.UserName, Email = model.Email, FullName = model.FullName, Gender = model.Gender };
        var result = await UserManager.CreateAsync(user, model.Password);
        if (result.Succeeded)
        {
            result = await UserManager.AddToRoleAsync(user.Id, model.RoleName);
            await SignInManager.SignInAsync(user, isPersistent: false, rememberBrowser: false);
            // For more information on how to enable account confirmation and password reset please visit http://go.microsoft.com/fwlink/?LinkID=320771
            // Send an email with this link
            string code = await UserManager.GenerateEmailConfirmationTokenAsync(user.Id);
            var callbackUrl = Url.Action("ConfirmEmail", "Account", new { userId = user.Id, code = code }, protocol: Request.Url.Scheme);
            await UserManager.SendEmailAsync(user.Id, "Confirm your account", "Please confirm your account by clicking <a href=\"" + callbackUrl + "\">here</a>");
            return RedirectToAction("Index", "Home");
        }
        AddErrors(result);
    }
    // If we got this far, something failed, redisplay form
    return View(model);
}

Open AccountViewModels, then change RegisterViewModel class as below

public class RegisterViewModel
{
    [Required]
    [EmailAddress]
    [Display(Name = "Email")]
    public string Email { get; set; }
    [Display(Name = "User Name")]
    public string UserName { get; set; }
    [Display(Name = "Full Name")]
    public string FullName { get; set; }
    [Display(Name = "First Name")]
    public string FirstName { get; set; }
    [Display(Name = "Last Name")]
    public string LastName { get; set; }
    [Required]
    [StringLength(100, ErrorMessage = "The {0} must be at least {2} characters long.", MinimumLength = 6)]
    [DataType(DataType.Password)]
    [Display(Name = "Password")]
    public string Password { get; set; }
    [DataType(DataType.Password)]
    [Display(Name = "Confirm password")]
    [Compare("Password", ErrorMessage = "The password and confirmation password do not match.")]
    public string ConfirmPassword { get; set; }
    public bool Gender { get; set; }
    [Display(Name = "Phone Number")]
    public string PhoneNumber { get; set; }
    public string RoleName { get; set; }
}

Open Register view, then add Roles to the Register view

@model MvcDemo.Models.RegisterViewModel
@{
    ViewBag.Title = "Register";
}

<h2>@ViewBag.Title.</h2>

@using (Html.BeginForm("Register", "Account", FormMethod.Post, new { @class = "form-horizontal", role = "form" }))
{
    @Html.AntiForgeryToken()
    <h4>Create a new account.</h4>
    <hr />
    @Html.ValidationSummary("", new { @class = "text-danger" })
    <div class="form-group">
        @Html.LabelFor(m => m.RoleName, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.DropDownListFor(m => m.RoleName, new SelectList(ViewBag.Roles, "Value", "Text"), new { @class = "form-control" })
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(m => m.UserName, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.TextBoxFor(m => m.UserName, new { @class = "form-control" })
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(m => m.FullName, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.TextBoxFor(m => m.FullName, new { @class = "form-control" })
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(m => m.Gender, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.CheckBoxFor(m => m.Gender)
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(m => m.Email, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.TextBoxFor(m => m.Email, new { @class = "form-control" })
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(m => m.Password, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.PasswordFor(m => m.Password, new { @class = "form-control" })
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(m => m.ConfirmPassword, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.PasswordFor(m => m.ConfirmPassword, new { @class = "form-control" })
        </div>
    </div>
    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" class="btn btn-default" value="Register" />
        </div>
    </div>
}

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

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