C# 使用 Linq-to-SQL 添加多条记录
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Add Multiple record using Linq-to-SQL
提问by Ajay
I want to add Multiple rows into Table using Linq to SQL
我想使用 Linq to SQL 将多行添加到表中
public static FeedbackDatabaseDataContext context = new FeedbackDatabaseDataContext();
public static bool Insert_Question_Answer(List<QuestionClass.Tabelfields> AllList)
{
Feedback f = new Feedback();
List<Feedback> fadd = new List<Feedback>();
for (int i = 0; i < AllList.Count; i++)
{
f.Email = AllList[i].Email;
f.QuestionID = AllList[i].QuestionID;
f.Answer = AllList[i].SelectedOption;
fadd.Add(f);
}
context.Feedbacks.InsertAllOnSubmit(fadd);
context.SubmitChanges();
return true;
}
When I add records into list object i.e. faddthe record is overwrites with last value of AllList
当我将记录添加到列表对象中时，即fadd记录被AllList 的最后一个值覆盖
采纳答案by Adam
I'm late to the party, but I thought you might want to know that the for-loop is unnecessary. Better use foreach (you don't need the index).
我迟到了，但我想你可能想知道 for 循环是不必要的。更好地使用 foreach（您不需要索引）。
It gets even more interesting when you use LINQ (renamed method for clarity):
当您使用 LINQ（为了清晰起见，重命名方法）时，它会变得更加有趣：
public static void InsertFeedbacks(IEnumerable<QuestionClass.Tabelfields> allList)
{
var fadd = from field in allList
select new Feedback
{
Email = field.Email,
QuestionID = field.QuestionID,
Answer = field.SelectedOption
};
context.Feedbacks.InsertAllOnSubmit(fadd);
context.SubmitChanges();
}
By the way, you shouldn't keep one data context that you access all the time; it's better to create one locally, inside a using statement, that will properly handle the database disconnection.
顺便说一句，你不应该保留一个你一直访问的数据上下文；最好在 using 语句中在本地创建一个，以正确处理数据库断开连接。
回答by Yograj Gupta
You should create object of Feedback in the scope of for loop, so change your method to :
您应该在 for 循环范围内创建反馈对象，因此将您的方法更改为：
public static bool Insert_Question_Answer(List<QuestionClass.Tabelfields> AllList)
{
List<Feedback> fadd = new List<Feedback>();
for (int i = 0; i < AllList.Count; i++)
{
Feedback f = new Feedback();
f.Email = AllList[i].Email;
f.QuestionID = AllList[i].QuestionID;
f.Answer = AllList[i].SelectedOption;
fadd.Add(f);
}
context.Feedbacks.InsertAllOnSubmit(fadd);
context.SubmitChanges();
return true;
}
