我如何在從實體框架模型中檢索的linq查詢中調用方法

Question

我有以下代碼

return (_entities.Users.Select(profile => new ProfileUserListItemDto
                {
                    Email = profile.Email,
                    FirstName = profile.FirstName,
                    Id = profile.Id,
                    LastName = profile.LastName,
                    Role = DtoEntityLookups.EntityRoleToDtoRole(profile.Role),
                    TimeZone = profile.TimeZone
                })).ToList();

public static RoleTypeEnum EntityRoleToDtoRole(Role role)
        {
            if (role == null)
                throw new NoNullAllowedException("Null role supplied to EntityRoleToDtoRole method");

            if (role.Id.ToString() == RolesGuid.AdministratorGuid)
                return RoleTypeEnum.Administrator;
            if (role.Id.ToString() == RolesGuid.ClientGuid)
                return RoleTypeEnum.Client;

            throw new InvalidDataException("Unknown role supplied");
        }

調用時，出現以下錯誤

LINQ to Entities無法識別RoleTypeEnum EntityRoleToDtoRole（User.Entities.Entities.Role）'方法，並且該方法無法轉換為商店表達式。

如何將EntityRoleToDtoRole轉換為可從Entity Framework查詢中調用？

Answer 1

您需要使用Users.AsEnumerable（）才能在linq中調用方法。

return (_entities.Users.AsEnumerable().Select(profile => new ProfileUserListItemDto
                {
                    Email = profile.Email,
                    FirstName = profile.FirstName,
                    Id = profile.Id,
                    LastName = profile.LastName,
                    Role = DtoEntityLookups.EntityRoleToDtoRole(profile.Role),
                    TimeZone = profile.TimeZone
                })).ToList();