如何通过linq在ASPNET身份中以特定角色检索用户

Question

我需要检索特定角色的所有用户，我认为应该简单地使这是问题。但是，这是问题。

Applicationuser的角色导航属性不是角色列表（IdentityRole），而是链接用户和角色的中间表（IdentitySerroles）的集合。因此，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

类型"系统。 mscorlib.dll，但未在用户代码中处理

其他信息：无法创建类型的常数值 'Microsoft.aspnet.Identity.entityFramework.IdentityUserrole'。仅有的 在这种情况下支持原始类型或枚举类型。

如何做到这一点，为什么导航属性不是角色集合，这可能是我们需要报告的错误？

Answer 1

错误消息很清楚：您在收集非主要对象时无法调用Contains。

尝试以下内容：

    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();

Answer 2

我敢肯定，身份框架中有一个API可以这样做。但是除了您的例外，请尝试：

&& client.Roles.Count(r => r.Name == "client") > 0