How to get the role a user belongs to without having to check against all the position roles I have in my database in ASP.NET

I'm working with Roles for my asp.net webform application. I have all have RoleName already saved in database. What i want to achieve though, is that when a user logs in, i want to get the roleName of the user so as to use it for another thing(to query to Db for a specific result to be displayed.) i have tried to use

<pre>var userRole = Roles.GetRolesForUser(user.Value);

<pre lang="text">if (Membership.ValidateUser(user.Value, Password.Value))
      {
              var userRole = Roles.GetRolesForUser(user.Value);
     var GetSomeRecords = users.Where(m => m.Myrole == userRole).ToList();
        }