Linq Include from List<string>

本文关键字：string gt Include lt List Linq from | 更新日期: 2023-09-27 18:02:53

是否可以从列表中指定" include " ?

我有一个可能包含的子表列表:

List<string> includedTables

我当前的数据库调用是这样的:

return db.SA_Items
       .Where(x => x.LastUpdated > lastUpdated)
       .Where(x => x.Active == true)
       .OrderBy(x => x.ItemID)
       .Skip(offset)
       .Take(limit)
       .ToList();

我想以某种方式在列表中添加foreach字符串，并将.Include(....)添加到数据库调用…

例如，如果列表中有两个字符串，那么代码将等价于: 
return db.SA_Items
       .Include("first string in the list")
       .Include("second string in the list")
       .Where(x => x.LastUpdated > lastUpdated)
       .Where(x => x.Active == true)
       .OrderBy(x => x.ItemID)
       .Skip(offset)
       .Take(limit)
       .ToList();

List也有可能为空。

是否有可能以某种方式动态地做到这一点?

有谁能给我点建议吗?

Linq Include from List<string>

当然，您可以通过以下几个步骤构建您的查询:

IQueryable<SA_Item> query=db.SA_Items;
if(includedTables!=null)
   query = includedTables.Aggregate(query, (current, include) => current.Include(include));
query=query.Where(x => x.LastUpdated > lastUpdated)
           .Where(x => x.Active == true)
           .OrderBy(x => x.ItemID)
           .Skip(offset)
           .Take(limit);
return query.ToList();// Materialize your query

你可以做类似的事情发生在下面的stackoverflow链接，但替换int索引已添加到您的字符串:

LINQ: Add RowNumber Column

您可以使用concat。

return db.SA_Items
       .Concat(new string[] {"first string in the list", "second string in the list"})
       .Where(x => x.LastUpdated > lastUpdated)
       .Where(x => x.Active == true)
       .OrderBy(x => x.ItemID)
       .Skip(offset)
       .Take(limit)
       .ToList();
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