异步 lambda 表达式未编译

Question

我有一个带有 Select 的 lambda 表达式，其中创建了一个新的 ResourcesResponse.Resource 对象。 Resource 对象有一个计算出的 Order 字段，该字段调用名为 GetResourceTypeOrder 的异步存储库方法，所有内容如下所示：

ResourcesResponse instantiation:

var tmp = new ResourcesResponse
{
    Cost = aux.Sum(s => s.Cost),
    Resources = aux
        .OrderBy(k => k.Order)
        .ThenBy(k => k.TypeId)
        .Select(async s => new ResourcesResponse.Resource
        {
            Id = ((ulong)s.Id).ToString(),
            Charge = s.Charge,
            Cost = s.Cost,
            CurrencyCode = s.CurrencyCode,
            ForecastCharge = s.ForecastCharge,
            ForecastCost = s.ForecastCost,
            ForecastUsedUnits = s.ForecastUsedUnits,
            ParentId = ((ulong?)s.ParentId).ToString(),
            Order = await _resourcesRepository.GetResourceTypeOrder(s.TypeId),
            Rate = s.Rate,
            TypeId = s.TypeId,
            UsedUnits = s.UsedUnits,
        })
        .ToArray(),
    Id = ((ulong)entry.Id).ToString(),
    Name = entry.Name,
    Description = entry.Description,
    OriginalId = entry.OriginalId,
    ResourceTypeId = entry.ResourceTypeId,
    ResourceType = await _resourcesRepository.GetResourceTypeName(entry.ResourceTypeId),
    Order = await _resourcesRepository.GetResourceTypeOrder(entry.ResourceTypeId),
    State = entry.State,
    Zone = entry.Zone,
    Charge = aux.Sum(s => s.Charge),
};

ResourceResponse:

public class ResourcesResponse
{
    public string Id { get; set; } = default!;
    public string Name { get; set; } = default!;
    public string? Description { get; set; } = default!;
    public string OriginalId { get; set; } = default!;
    public string ResourceType { get; set; } = default!;
    [JsonIgnore]
    public int? Order { get; set; } = default!;
    public ResourceTypeValues ResourceTypeId { get; set; }
    public string? CurrencyCode => Resources?.FirstOrDefault()?.CurrencyCode;
    public decimal? Charge { get; set; }
    public decimal Cost { get; set; }
    public decimal? ForecastCharge { get; set; }
    public decimal? ForecastCost { get; set; }
    public string Zone { get; set; } = default!;
    public string State { get; set; } = default!;
    public Resource[] Resources { get; set; } = default!;

    public sealed class Resource
    {
        [JsonIgnore]
        public string Id { get; set; } = default!;
        [JsonIgnore]
        public string? ParentId { get; set; } = default!;
        [JsonIgnore]
        public int? Order { get; set; } = default!;
        public string CurrencyCode { get; set; } = default!;
        public decimal Rate { get; set; }
        public long UsedUnits { get; set; }
        public decimal Cost { get; set; }
        public decimal? Charge { get; set; }
        public long? ForecastUsedUnits { get; set; }
        public decimal? ForecastCost { get; set; }
        public decimal? ForecastCharge { get; set; }
        public string Type { get; set; } = default!;
        public ResourceTypeValues TypeId { get; set; }
        public string? Unit { get; set; } = default!;
        public bool? Hourly { get; set; } = default!;
    }
}

ResourceTypeOrder:

public async Task<int?> GetResourceTypeOrder(ResourceTypeValues resourceTypeId)
{
    ICache.Operation<int?> myTableCacheImplementation = async delegate (string key)
    {
        var dic = await _repositoryResourceTypes.FindAll().ToDictionaryAsync(k => k.Id);
        return dic[resourceTypeId].Order;
    };

    return await _vdcCache.GetOrCreateAsync(ResourceTypeCacheKey.ResourceTypeOrder, myTableCacheImplementation, null);
}

我的问题是我不知道在哪里放置缺少的 await （或者编译器接受整个表达式所需的任何内容）。

对于父级 ResourceResponse 还有一个计算的 Order 字段，但正如您所看到的，它是正确的。

很明显，我可以在 GetResourceTypeOrder 的末尾添加 .Result 并删除异步运算符，但这不是 async / wait 的想法。

Answer 1

我自己回答：

处理此问题的方法（以 @Fildor 注释为起点）是重构 GetResourceTypeOrder 方法，使其返回 完整的字典，而不是特定元素。然后，我只需在创建 ResourcesResponse 实例之前检索字典，并获取并将相应的 Order 分配给“Order”字段，即 resourceTypes[s.TypeId].Order:

var resourceTypes = await _resourcesRepository.GetResourceTypes();

var tmp = new ResourcesResponse
{
    Cost = aux.Sum(s => s.Cost),
    Resources = aux
        .OrderBy(k => k.Order)
        .ThenBy(k => k.TypeId)
        .Select(s => new ResourcesResponse.Resource
        {
            Id = ((ulong)s.Id).ToString(),
            Charge = s.Charge,
            Cost = s.Cost,
            CurrencyCode = s.CurrencyCode,
            ForecastCharge = s.ForecastCharge,
            ForecastCost = s.ForecastCost,
            ForecastUsedUnits = s.ForecastUsedUnits,
            ParentId = ((ulong?)s.ParentId).ToString(),
            Order = resourceTypes[s.TypeId].Order,
            Rate = s.Rate,
            TypeId = s.TypeId,
            UsedUnits = s.UsedUnits,
        }).ToArray(),
    Id = ((ulong)entry.Id).ToString(),
    Name = entry.Name,
    Description = entry.Description,
    OriginalId = entry.OriginalId,
    ResourceTypeId = entry.ResourceTypeId,
    ResourceType = await _resourcesRepository.GetResourceTypeName(entry.ResourceTypeId),
    Order = await _resourcesRepository.GetResourceTypeOrder(entry.ResourceTypeId),
    State = entry.State,
    Zone = entry.Zone,
    Charge = aux.Sum(s => s.Charge),
};