C# 使用 Linq，从另一个 List<int> 中的列表中获取所有项目
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Using Linq, get all items from list that are in another List<int>
提问by Ali Issa
I have the following scenario:
a list of int: List<int> idsOnly = new List<int>();and another list of object that should bring all items that their ids matching the list idsOnly
我有以下场景：一个 int:List<int> idsOnly = new List<int>();列表和另一个对象列表，该列表应该包含其 ID 与列表 idsOnly 匹配的所有项目
var myList = db.Items.Where(item => idsOnly.Contains(item.ID.Value))
.Select(a => new { a.Title })
.ToList();
I only need to get the titles from the myList
我只需要从 myList 中获取标题
Any help will be appreciated
任何帮助将不胜感激
采纳答案by cuongle
Your code works but it will create the list of anonymous object, not string type
您的代码有效，但它会创建匿名对象列表，而不是字符串类型
Instead of using (a => new { a.Title }, you just use a => a.Titleif you just only want to get the title:
如果您只想获得标题(a => new { a.Title }，您只需使用，而不是使用a => a.Title：
var myList = db.Items.Where(item => idsOnly.Contains(item.ID.Value))
.Select(a => a.Title).ToList();
回答by Jan P.
var myList =
(from item in db.Items
where idsOnly.Contains(item.ID.Value)
select item.Title).ToList()
回答by Tim Schmelter
You can use a Join
你可以使用一个 Join
var titlesInIdList = from item in db.Items
join id in idsOnly
on item.ID.Value equals id
select item.Title;
var list = titlesInIdList.ToList();
回答by Aghilas Yakoub
You can try with (If problem conversion : Convert to int your Id, if is not of int type)
您可以尝试使用（如果转换有问题：转换为 int 您的 ID，如果不是 int 类型）
var myList = db.Items.Where(item => (idsOnly.Contains(Convert.ToInt32(item.ID.Value)))).Select(a => a.Title ).ToList();
Without conversion
无需转换
var myList = db.Items.Where(item => (idsOnly.Contains(item.ID.Value))).Select(a => a.Title ).ToList();
回答by rahul_k
var Result = (from item in db.Items
join id in idsOnly
on item.ID.Value equals id
select new {item.Title}).ToList(); //Here U can return ToArray or ToList()
