更改表值时未更新Linq [英] Linq Not Updatd When Changeing Table Value

问题描述

是否有任何选项可以使用linq来获取更新的数据，而无需重新查询可查询对象

Is there any option get the updated data using linq without requering the quriable object

推荐答案

您实际上有点不精确，但我会尝试:

假设您有:

Hi,

you are in fact a little unprecise, but I''ll try:

Assume you have:

List<int> numbers = new List<int>(new int[] { 1, 2, 3, 4, 5, 6, 7 });
var odds =
   from number in numbers
   where (number % 2) == 1
   select number;

每当您添加另一个数字(比方说:13)时，随后的赔率调用将自动反映更改(新结果是:1、3、5、7、13).如果是您所要求的，那就没有选择，也没有必要.

如果您正在考虑以下内容:

Whenever you add another number (let''s say: 13) a subsequent call to odds will automatically reflect the changes (the new result is: 1,3,5,7,13). If that is, what you asked, then there is no option and there is no need for.

If you''re thinking of something like:

// continue the above code
List<int> oddnumbers = odds.ToList();
numbers.Add(13);

那么奇数"是一个完全新的对象，与数字"或奇数"无关/没有链接.因此它不包含"13".当您在查询定义语句(或"ToArray()"或"let")中使用ToList()方法时，也是如此.

如果您需要反映数字"中的更改，则可以使用ObservableCollection而不是List并在CollectionChanged事件上重新查询.但是，如果要处理大型结果集，请务必留意您的记忆.

干杯

then ''oddnumbers'' is a completly new object that has nothing to do with/no link to ''numbers'' or ''odds''. So it does not contain the ''13''. The same applies when you''re using the ToList()-method in the query definition statement (or ''ToArray()'' or ''let'').

If you need to reflect changes in ''numbers'', you could use an ObservableCollection instead of a List and requery upon the CollectionChanged-event. But be sure to keep an eye on your memory if you''re dealing with large resultsets.

Cheers

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