c# - LINQ to Entities 无法识别方法 NotSupportedException

Question

LINQ 到 EF:

 db.ReadonlyQuery<Transaction>()
     .Select(t => new ACurrentDayInfo
         {
              OrderId = t.TransactionIdentifier,
              OrderTime = t.TransactionTime,
              UserName = JsonConvert.DeserializeObject<UserInfo>(t.UserInfo).RealName ?? ""
         })
     .ToListAsync();

t.UserInfo 是一个 json 字符串，如 {"RealName ":"XY"} 在表字段的每个记录中。如何将其转换为服务器查询？

Answer 1

用这样的 getter 扩展你的 ACurrentDayInfo 类

class  ACurrentDayInfo
{
    public string UserName
    {
        get
        {
            return JsonConvert.DeserializeObject<UserInfo>(UserInfo).RealName ?? "";
        }
    }
}

并像这样修改您的查询:

db.ReadonlyQuery<Transaction>()
                    .Select(t => new ACurrentDayInfo
                    {
                        OrderId = t.TransactionIdentifier,
                        OrderTime = t.TransactionTime,
                        UserInfo = t.UserInfo
                    }).ToListAsync();