"ToListAsync()" 和 "AsAsyncEnumerable().ToList()" 之间的区别

Question

函数需要returnTask<List<Record>> 下面两个选项都是returning Task<List<Record>>，哪个更高效？这里有什么标准的方法吗？

选项 1：

Task<List<Record>> GetRecords()
{
    return 
    DbContext.Set<Record>.Where(predicate).ToListAsync();
}

选项 2：

Task<List<Record>> GetRecords()
{
    return
    DbContext.Set<Record>.Where(predicate).AsAsyncEnumerable().ToList();
}

Answer 1

请注意，这是 .NET Core 3.x 之前的回答。
在下方@IanKemp 的评论中找到更新。

选择选项 1 ToListAsync，因为 AsAsyncEnumerable 的 source code 明确提到

This is an internal API that supports the Entity Framework Core infrastructure and not subject to the same compatibility standards as public APIs. It may be changed or removed without notice in any release. You should only use it directly in your code with extreme caution and knowing that doing so can result in application failures when updating to a new Entity Framework Core release.

official documentation提到

This API supports the Entity Framework Core infrastructure and is not intended to be used directly from your code. This API may change or be removed in future releases.

Answer 2

虽然 pfx 的现有答案对于 .NET Core 2.x 及更早版本仍然适用，但 AsAsyncEnumerable 已正式添加到 .NET Core 3.x。有关详细信息，请参阅 Ian Kemp 的评论。