Why role.Name can get data? - asp.net

Question

I built "Role edit page" but role.Name can't get role data and It Happens NulReference eror. There is Two role in data but role.Name isn`t get them I research about that But I can't fixed this problem
what do you think about that?
Please Help me I Don't know what am I doing
Controller
public async Task<IActionResult> RoleEdit(string id)
{
var role = await _roleManager.FindByIdAsync(id);
var members = new List<User>();
var nonMembers = new List<User>();
foreach (var user in _userManager.Users.ToList())
{
var list = await _userManager.IsInRoleAsync(user, role.Name) ?
members : nonMembers;
list.Add(user);
}
var model = new RoleDetails()
{
Role = role,
Members = members,
NonMembers = nonMembers
};
return View();
}
RoleEdit View
#model RoleDetails
<div class="row">
<div class="col-md-12">
<form asp-controller="Admin" asp-action="RoleEdit">
<h6 class="bg-info text-white p-1"> Add To #Model.Role.Name</h6>
<table>
#if (Model.NonMembers.Count() == 0)
{
<tr>
<td>
Bütün istfadəçilər rola aid
</td>
</tr>
}
else
{
foreach (var user in Model.NonMembers)
{
<tr>
<td>
#user.UserName
</td>
<td>
<input type="checkbox" name="IdsToAdd" value="#user.Id" />
</td>
</tr>
}
}
</table>
<hr />
</form>
</div>
</div>

Answer 1

Try this:
public ActionResult Edit(string id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
RoleDetails roleDetails = db.RoleDetails.Find(id);
if (RoleDetails == null)
{
return HttpNotFound();
}
return View(RoleDetails);
}
I don't know what your database name is but you can change it.
If your goal is to have a crud system try this