Cannot update user Identity Role from list in razor page - asp.net-core

Question

I have a razor page which shows checkbox of Roles. The Roles owned by the selected user will be checked on page load. What I'm trying to do is, I want to be able to edit the roles for the selected user. But when I click update, it doesn't update.
Here is the razor page:
<EditForm Model="#RoleDto" OnValidSubmit="#EditRole">
<DataAnnotationsValidator />
<ValidationSummary />
<div class="card">
<div class="card-header">
<h2>Manage User Roles</h2>
Add/Remove Roles for User / #UserFullname
</div>
<div class="card-body">
#for (int i = 0; i < numOfRoles; i++)
{
<div class="form-check m-1">
<input type="hidden" value="#RoleListModel[i].Id" />
<input type="hidden" value="#RoleListModel[i].Name" />
<input type="checkbox" checked="#RoleListModel[i].Selected" /> #RoleListModel[i].Name
</div>
}
</div>
</div>
<button type="submit" class="btn btn-success btn-block">
Confirm
</button>
#code {
ApplicationRoleDto RoleDto = new ApplicationRoleDto();
private List<ApplicationRoleDto> RoleListModel;
[Parameter] public string Id { get; set; }
[Parameter] public ApplicationUserDto UserDto { get; set; }
[Parameter] public string UserFullname { get; set; }
[Parameter] public int numOfRoles { get; set; }
protected async override Task OnParametersSetAsync()
{
UserDto = await _client.GetFromJsonAsync<ApplicationUserDto>($"api/userroles/{Id}");
UserFullname = UserDto.FullName;
RoleListModel = await _client.GetFromJsonAsync<List<ApplicationRoleDto>>($"api/rolemanager/{Id}");
numOfRoles = RoleListModel.Count();
}
async Task EditRole()
{
await _client.PostAsJsonAsync($"api/rolemanager/{Id}", RoleListModel);
_navManager.NavigateTo($"/userroles/");
}
}
and here is the controller:
[HttpPost]
public async Task<IActionResult> Manage(List<ApplicationRoleDto> model, string Id)
{
var user = await _userManager.FindByIdAsync(Id);
if (user == null)
{
NotFound();
}
var roles = await _userManager.GetRolesAsync(user);
var result = await _userManager.RemoveFromRolesAsync(user, roles);
if (!result.Succeeded)
{
Console.WriteLine("Cannot remove user existing roles");
return NotFound();
}
result = await _userManager.AddToRolesAsync(user, model.Where(x => x.Selected).Select(y => y.Name));
if (!result.Succeeded)
{
Console.WriteLine("Cannot add selected roles to user");
return NotFound();
}
return NoContent();
}
Did I miss anything here?