如何在dotnet core中使用Entity Framework进行数据获取

本文介绍了如何在dotnet core中使用Entity Framework进行数据获取的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我有一个名为 UserAnswers的表。以下屏幕快照包含表数据 I have a table called "UserAnswers".below screenshot contains table data我要例如有一个名为 [email protected]的用户。该用户包含4记录为SurveyId。 我想像下面这样for an exampleThere is a user called "[email protected]".this user contains 4 records for a SurveyId.I want to get this like belowAnswers : [ {"2"}, {"1","0","1","1"}, {"1","2","4","3"}, {"Blue"}] 但是我的代码为每一行返回此数组。我的意思是返回重复的记录。But my code returns this array for every rows.I meant duplicate records returning.这是我的代码 var qstns = await (from uans in _context.UserAnswers where uans.SurveyId == id select new UserAnswersReturnDto { UserEmail = uans.CreatedBy, Qustns = (from ans in _context.UserAnswers where ans.CreatedBy == uans.CreatedBy select new UserAnswersSet { QNo = ans.QNo, Ansrs = JsonConvert.DeserializeObject<JArray>(string.IsNullOrEmpty(ans.Answers) ? "[]" : ans.Answers) }).ToArray() }).ToListAsync();如何解决这个问题。我为此问题开了很多问题，但没人回答。谢谢。So how to solve this issue.I opened many questions for this problem,but no one answered.Please help me.Thanks in advanced推荐答案您需要对数据进行实际分组，然后返回：You need to actually group your data before returning:我使用LINQ Lambda表示法，但是如果您愿意，应该可以很容易地将其转换回查询：I used LINQ Lambda notation, but it should be quite easy to translate back to query if you're so inclined:var qstns = _context.UserAnswers.Where(uans => uans.SurveyId == id) .GroupBy(uans => uans.CreatedBy) .Select(grans => new UserAnswersReturnDto { UserEmail = grans.Key, Qustions = grans.Select(ans => new UserAnswersSet() { QNo = ans.QNo, Ansrs = ans.Answers }).ToList() } ).ToList();我没有时间仔细检查这一点，但我希望它能为您提供指导帮助您解决问题！I didn't have time to double-check this, but I hope it serves as a guide to help you solve your issue! 这篇关于如何在dotnet core中使用Entity Framework进行数据获取的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！