英文:
List<order>' does not contain a definition for 'GetAwaiter'
问题
我实际上面临一个奇怪的问题。我实际上正在尝试通过查找特定的ID来返回数据列表。一切都应该正常工作，但我不明白为什么会遇到这个令人烦恼的错误。以下是我的代码。
order.cs:
public class order
{
public int Id { get; set; }
public int? Seid { get; set; }
public AppUser Seuser { get; set; }
public int? Reid { get; set; }
public AppUser Reuser { get; set; }
public string Status { get; set; }
}
Controller:
[HttpGet]
public async Task<ActionResult<IEnumerable<order>>> GetOrder()
{
var currentuserid = int.Parse(User.GetUserId());
var r = await _orderRepository.GetOrders(currentuserid);
if(r != null)
{
return Ok(r);
}
return BadRequest();
}
orderRepository:
public async Task<IEnumerable<order>> GetOrders(int id)
{
return await _context.Orders.Where(x => x.Seid == id).ToListAsync(); //主要出错的地方是添加了await时
}
错误信息:
List<order>不包含GetAwaiter的定义，也没有可访问的扩展方法GetAwaiter，接受第一个参数类型为List<order>(是否缺少 using 指令或程序集引用?) [API]csharp(CS1061)
当我从这行代码中删除 await 时：return await _context.Orders.Where(x => x.Seid == id).ToListAsync();，然后错误消失。但是当我运行我的应用程序时，我发现了一个不同的错误，仅适用于这个 await 情况。我是一个绝对的初学者。我该如何解决这个问题？
英文:
I am actually facing a strange problem. I am actually trying to return list of data by find specific id. Everything should work but I don't understand why I am facing this annoying error. Here is my code below.
order.cs:
public class order
{
public int Id { get; set; }
public int? Seid { get; set; }
public AppUser Seuser { get; set; }
public int? Reid { get; set; }
public AppUser Reuser { get; set; }
public string Status { get; set; }
}
Controller:
[HttpGet]
public async Task <ActionResult<IEnumerable<order>>>GetOrder()
{
var currentuserid = int.Parse(User.GetUserId());
var r = await _orderRepository.GetOrders(currentuserid);
if(r!=null)
{
return Ok(r);
}
return BadRequest();
}
orderRepository:
public async Task<IEnumerable<order>> GetOrders(int id)
{
return await _context.Orders.Where(x => x.Seid == id).ToList(); //here mainly found error when added await
}
Error:
> List<order> does not contain a definition for GetAwaiter and no
> accessible extension method GetAwaiter accepting a first argument of
> type List<order> could be found (are you missing a using directive
> or an assembly reference?) [API]csharp(CS1061)
When I remove await to this line of code:- return await _context.Orders.Where(x => x.Seid == id).ToList(); then error gone. But when I run my application I found a different error just for this await case. I am an absolute beginner. How I can resolve this problem?
答案1
得分: 0
你只能await定义了GetAwaiter()的对象。尝试移除await，或使用ToListAsync()。
另外，如果你的实现不明确需要返回一个List，我建议只返回一个IEnumerable：
public async Task<IEnumerable<order>> GetOrders(int id)
{
return _context.Orders.Where(x => x.Seid == id);
}
如果必须返回一个List，我建议更改方法签名以反映你将始终返回一个List：
public async Task<List<order>> GetOrders(int id)
{
return _context.Orders.Where(x => x.Seid == id).ToListAsync();
}
英文:
You can only await objects that define GetAwaiter().
Try removing the await, or using ToListAsync().
As a side note, if your implementation doesn't explicitly require a List, I'd suggest just returning an IEnumerable:
public async Task<IEnumerable<order>> GetOrders(int id)
{
return _context.Orders.Where(x => x.Seid == id);
}
If you are required to return a List, I'd suggest changing the method signature to reflect that you'll always return a List:
public async Task<List<order>> GetOrders(int id)
{
return _context.Orders.Where(x => x.Seid == id).ToListAsync();
}
</details>
# 答案2
**得分**: -1
尝试使用 [`IAsyncEnumerable<T>`][1] 接口，它提供了对指定类型的值进行异步迭代的功能：
``` c#
public async IAsyncEnumerable<List<order>> GetOrders(int id)
{
yield return await _context.Orders.Where(x => x.Seid == id).ToListAsync<order>();
}
查看 编译器错误 CS1983 的说明。
英文:
Try to use IAsyncEnumerable<T> interface that provides asynchronous iteration over values of a specified type:
public async IAsyncEnumerable<List<order>> GetOrders(int id)
{
yield return await _context.Orders.Where(x => x.Seid == id).ToListAsync<order>();
}
See description of the Compiler Error CS1983
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