public interface IQueryableRoleStore<TRole> : IRoleStore<TRole>, IDisposable where TRole : class
   {
     IQueryable<TRole> Roles { get; }
   }
   public interface IRoleStore<TRole> : IDisposable where TRole : class
   {
     Task<IdentityResult> CreateAsync(TRole role, CancellationToken cancellationToken);
     Task<IdentityResult> DeleteAsync(TRole role, CancellationToken cancellationToken);
     Task<TRole> FindByIdAsync(string roleId, CancellationToken cancellationToken);
     Task<TRole> FindByNameAsync(string normalizedRoleName, CancellationToken cancellationToken);
     Task<string> GetNormalizedRoleNameAsync(TRole role, CancellationToken cancellationToken);
     Task<string> GetRoleIdAsync(TRole role, CancellationToken cancellationToken);
     Task<string> GetRoleNameAsync(TRole role, CancellationToken cancellationToken);
     Task SetNormalizedRoleNameAsync(TRole role, string normalizedName, CancellationToken cancellationToken);
     Task SetRoleNameAsync(TRole role, string roleName, CancellationToken cancellationToken);
    Task<IdentityResult> UpdateAsync(TRole role, CancellationToken cancellationToken);
   }

 public class HDRoleStore<TRole> : IQueryableRoleStore<TRole>
      where TRole : HDRole, new()
    {
      /// <summary>
      /// 存储所有预定义的角色
      /// </summary>
      private readonly Dictionary<string, TRole> _roles = new Dictionary<string, TRole>();
      /// <summary>
     /// 所有角色
     /// </summary>
     public IQueryable<TRole> Roles
     {
       get
       {
         if (_roles.Count == )
         {
           TRole role = new TRole();
           role.Id = "admin";
           role.Name = "管理员";
           _roles.Add(role.Id, role);
           role = new TRole();
           role.Id = "user";
           role.Name = "用户";
           _roles.Add(role.Id, role);
           role = new TRole();
           role.Id = "power";
           role.Name = "大虾";
           _roles.Add(role.Id, role);
         }
         return _roles.Values.AsQueryable();
       }
     }
     public Task<IdentityResult> CreateAsync(TRole role, CancellationToken cancellationToken)
     {
       _roles[role.Id] = role;
       return Task.FromResult(IdentityResult.Success);
     }
     public Task<IdentityResult> DeleteAsync(TRole role, CancellationToken cancellationToken)
     {
       if (role == null || !_roles.ContainsKey(role.Id))
       {
         throw new InvalidOperationException("Unknown role");
       }
       _roles.Remove(role.Id);
       return Task.FromResult(IdentityResult.Success);
     }
     public void Dispose()
     {
     }
     public Task<TRole> FindByIdAsync(string roleId, CancellationToken cancellationToken)
     {
       if (_roles.ContainsKey(roleId))
       {
         return Task.FromResult(_roles[roleId]);
       }
       return Task.FromResult<TRole>(null);
     }
     public Task<TRole> FindByNameAsync(string normalizedRoleName, CancellationToken cancellationToken)
     {
       return
          Task.FromResult(
            Roles.SingleOrDefault(r => String.Equals(r.Name, normalizedRoleName, StringComparison.OrdinalIgnoreCase)));
     }
     public Task<string> GetNormalizedRoleNameAsync(TRole role, CancellationToken cancellationToken)
     {
       return Task.FromResult(role.Name);
     }
     public Task<string> GetRoleIdAsync(TRole role, CancellationToken cancellationToken)
     {
       return Task.FromResult(role.Id);
     }
     public Task<string> GetRoleNameAsync(TRole role, CancellationToken cancellationToken)
     {
       return Task.FromResult(role.Name);
     }
     public Task SetNormalizedRoleNameAsync(TRole role, string normalizedName, CancellationToken cancellationToken)
     {
       role.Name = normalizedName;
       return Task.FromResult();
     }
     public Task SetRoleNameAsync(TRole role, string roleName, CancellationToken cancellationToken)
     {
       role.Name = roleName;
       return Task.FromResult();
     }
     public Task<IdentityResult> UpdateAsync(TRole role, CancellationToken cancellationToken)
     {
       _roles[role.Id] = role;
       return Task.FromResult(IdentityResult.Success);
     }
   }