linq - 如何通过 ASPnet Identity 中的 Linq 检索具有特定角色的用户

Question

我需要检索特定角色的所有用户，我认为这应该很简单，但是，这里是问题所在。

ApplicationUser 的 Roles 导航属性不是角色列表(IdentityRole)，而是链接用户和角色的中间表(IdentityUserroles)的集合。所以，这是我拥有的代码，但它不起作用。

[HttpPost]
[Authorize(Roles = "Admin, Recepcionista, Orientador")]
public ActionResult SearchResults(SearchCriteriaViewModel criteria)
{


    List<SearchResultViewModel> results = new List<SearchResultViewModel>();
    var clients = new List<ApplicationUser>();

    using (var context = new ApplicationDbContext())
    {
        IdentityUserRole role = new IdentityUserRole();
        var tempRole = (from _role in context.Roles
                        where _role.Name == "client"
                        select _role).FirstOrDefault();
        role.Role = tempRole;

        clients = (from client in context.Users
                   where client.Email.Contains(criteria.SearchCriteria)
                   || client.FirstName.Contains(criteria.SearchCriteria)
                   || client.MiddleName.Contains(criteria.SearchCriteria)
                   || client.LastName.Contains(criteria.SearchCriteria)
                   || client.SecondLastName.Contains(criteria.SearchCriteria)
                   || client.UserName.Contains(criteria.SearchCriteria)
                   && client.Roles.Contains(role)
                   select client).ToList();


    }

    foreach (var client in clients)
    {
        results.Add(new SearchResultViewModel()
        {
            Email = client.Email,
            FirstName = client.FirstName,
            MiddleName = client.MiddleName,
            LastName = client.LastName,
            SecondLastName = client.SecondLastName,
            UserName = client.UserName
        });
    }

    SearchClientViewModel model = new SearchClientViewModel();
    model.SearchResults = results;

    return View("Index", model);

}

Linq 抛出以下异常

An exception of type 'System.NotSupportedException' occurred in mscorlib.dll but was not handled in user code

Additional information: Unable to create a constant value of type 'Microsoft.AspNet.Identity.EntityFramework.IdentityUserRole'. Only primitive types or enumeration types are supported in this context.

这怎么做，为什么导航属性不是角色的集合，这可能是我们需要报告的错误吗？

Answer 1

错误信息很明确:你不能调用Contains关于非原始对象的集合。

尝试以下操作:

    clients = (from client in context.Users
               where client.Email.Contains(criteria.SearchCriteria)
               || client.FirstName.Contains(criteria.SearchCriteria)
               || client.MiddleName.Contains(criteria.SearchCriteria)
               || client.LastName.Contains(criteria.SearchCriteria)
               || client.SecondLastName.Contains(criteria.SearchCriteria)
               || client.UserName.Contains(criteria.SearchCriteria)
               && client.Roles.Select(r => r.Name).Contains("client")
               select client).ToList();