Get list of users with assigned roles in asp.net identity 2.0

Question

I have a drop down list box which lists roles. I want to get the list of users having that role. I mean list of users that are in "Administrator" role or "CanEdit" role. Here is my code:

public IQueryable<Microsoft.AspNet.Identity.EntityFramework.IdentityUser> 
  GetRolesToUsers([Control] string ddlRole)
{    
  //ddlRole returns role Id, based on this Id I want to list users

  var _db = new ApplicationDbContext();
  IQueryable<Microsoft.AspNet.Identity.EntityFramework.IdentityUser> query = _db.Users;

  if (ddlRole != null)
  {
    //query = query.Where(e => e.Claims == ddlRole.Value);  ???????              
  }

  return query;
}

Please help.

Updated Code (still error)

public List<IdentityUserRole> GetRolesToUsers([Control]string ddlRole)
{

  var roleManager = 
   new RoleManager<IdentityRole>(new RoleStore<IdentityRole>(new ApplicationDbContext()));
  var users = roleManager.FindByName("Administrator").Users.ToList();
  return users;
}

Error: The Select Method must return one of "IQueryable" or "IEnumerable" or "Microsoft.AspNet.Identity.EntityFramework.IdentityUser" when ItemType is set to "Microsoft.AspNet.Identity.EntityFramework.IdentityUser".

I tried various castings but none of them helped.

UPDATE (working solution)

Thanks to chris544, his idea helped me to fix this. Here is working method:-

public List<ApplicationUser> GetRolesToUsers([Control]string ddlRole)
{
  var context = new ApplicationDbContext();
  var users =
    context.Users.Where(x => x.Roles.Select(y => y.RoleId).Contains(ddlRole)).ToList();

  return users;
}

Solution 1

Not an expert, but ...

There seemed to be no built in funcionality for this in Identity and I could not get it work from built in Roles also (it seems to not work with claims based Identity).

So I ended up doing something like this:

var users = context.Users        
    .Where(x => x.Roles.Select(y => y.Id).Contains(roleId))
    .ToList();

• x.Roles.Select(y => y.Id) gets a list of all role ids for user x
• .Contains(roleId) checks if this list of ids contains necessary roleId

Solution 2

I find the role by the role name input. After, I find list users by id of the role.

public List<ApplicationUser> GetUsersInRole(string roleName)
{
 var roleManager = 
  new RoleManager<IdentityRole>(new RoleStore<IdentityRole>(new  ApplicationDbContext()));
 var role = roleManager.FindByName(roleName).Users.First();
 var usersInRole = 
  Users.Where(u => u.Roles.Select(r => r.RoleId).Contains(role.RoleId)).ToList();
 return usersInRole;
}

Solution 3

If you want to avoid using the context directly you can use the RoleManager with the following snippet

roleManager.FindByName("Administrator").Users

or

roleManager.FindByName("CanEdit").Users

For a short discussion about this topic have a look at the this thread

Solution 4

Using the RoleManager gives you this solution:

if(roleManager.RoleExists("CanEdit"))
{
    var idsWithPermission = roleManager.FindByName("CanEdit").Users.Select(iur => iur.Id);
    var users = db.Users.Where(u => idsWithPermission.Contains(u.Id));
}

I'd be interested to hear if this was better or worse than the other solutions here.

Solution 5

There are three ways you can do it.

In the Controller current logged in user's role can be checked as follows,

  if(User.IsInRole("SysAdmin"))
        {

Outside Controller you can check whether a particular user belongs to a Role as follows:

 ApplicationUserManager UserManager = HttpContext.GetOwinContext().GetUserManager<ApplicationUserManager>();
        var roles = UserManager.GetRoles(userid);
        if (roles.Contains("SysAdmin"))
        {
        }

Do not forget to add namespace,

using Microsoft.AspNet.Identity.EntityFramework;
using Microsoft.AspNet.Identity;
using Microsoft.AspNet.Identity.Owin;

For some reasons like integration testing etc, you may directly want to use EF to find user's role as follows:

string userId = User.Identity.GetUserId();
        ApplicationDbContext db = new ApplicationDbContext();
        var role = (from r in db.Roles where r.Name.Contains("Admin") select r).FirstOrDefault();
        var users = db.Users.Where(x => x.Roles.Select(y => y.RoleId).Contains(role.Id)).ToList();
        if (users.Find(x => x.Id == userId) != null)
        {
            // User is in the Admin Role
        }

Hope it helps.

Thanks /dj @debug_mode

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