将方法转换为async

Question

我正在尝试使这个方法异步。

我发现了与我的问题相关的帖子(你可能认为这是重复的)，我不确定如何将它们应用到这个方法。

可能需要一些帮助。

public async Task<IEnumerable<E2307DetailsViewModel>> GetE2307Details(long headerID)
{
// it's slow here; takes a lot of steps when finding the header Id
var E2307Details = await entities.AP_SUPPLIER_2307.AsEnumerable().Where(x => x.AP_2307_HDR_ID == headerID).Select(x => new E2307DetailsViewModel
{
APSupplier2307ID = x.AP_SUPPLIER_2307_ID,
AP2307HeaderID = x.AP_2307_HDR_ID,
UploadFileID = x.UL_ID,
TransactionAPJEID = x.TRANS_APJE_ID,
TransactionDescription = x.TRANS_DESCRIPTION,
TransactionDate = x.TRANS_DATE,
ReferenceNo = x.REFERENCE_NO,
InvoiceNo = x.INVOICE_NO,
ATCCode = x.ATC_CODE,
TaxRate = x.TAX_RATE,
AmtOfTaxWithHeld = x.AMOUNT_OF_TAX_WITHHELD,
ForTheMonthOf = GetUploadFileDetails(x.UL_ID).FOR_THE_MONTH_OF,
IncomePayment = x.AMOUNT_OF_TAX_WITHHELD / (x.TAX_RATE / 100),
MonthNo = GetUploadFileDetails(x.UL_ID).FOR_THE_MONTH_OF_NO.GetValueOrDefault(0),
NatureOfPayment = GetTaxCode().FirstOrDefault(y => y.ATCCode == x.ATC_CODE).NatureOfPayment,
ForTheYearOf = GetUploadFileDetails(x.UL_ID).FOR_THE_YEAR
});
return E2307Details;
}

编辑:我试着用'FirstOrDefaultAsync'替换'Where'，但它说

IEnumerable不包含的定义"FirstOrDefaultAsync">

编辑:当我在调试模式下检查这个并尝试"步骤进入"时，在这个代码Where(x => x.AP_2307_HDR_ID == headerID)中需要太多时间，因此为什么我试图使这个方法异步。

Answer 1

您可能需要像这样重写方法:

public async Task<IEnumerable<E2307DetailsViewModel>> GetE2307Details(long headerID)
{
// it's slow here; takes a lot of steps when finding the header Id
var E2307Details = (await entities.AP_SUPPLIER_2307.Where(x => x.AP_2307_HDR_ID == headerID).ToListAsync())
.Select(x => new E2307DetailsViewModel
{
APSupplier2307ID = x.AP_SUPPLIER_2307_ID,
AP2307HeaderID = x.AP_2307_HDR_ID,
UploadFileID = x.UL_ID,
TransactionAPJEID = x.TRANS_APJE_ID,
TransactionDescription = x.TRANS_DESCRIPTION,
TransactionDate = x.TRANS_DATE,
ReferenceNo = x.REFERENCE_NO,
InvoiceNo = x.INVOICE_NO,
ATCCode = x.ATC_CODE,
TaxRate = x.TAX_RATE,
AmtOfTaxWithHeld = x.AMOUNT_OF_TAX_WITHHELD,
ForTheMonthOf = GetUploadFileDetails(x.UL_ID).FOR_THE_MONTH_OF,
IncomePayment = x.AMOUNT_OF_TAX_WITHHELD / (x.TAX_RATE / 100),
MonthNo = GetUploadFileDetails(x.UL_ID).FOR_THE_MONTH_OF_NO.GetValueOrDefault(0),
NatureOfPayment = GetTaxCode().FirstOrDefault(y => y.ATCCode == x.ATC_CODE).NatureOfPayment,
ForTheYearOf = GetUploadFileDetails(x.UL_ID).FOR_THE_YEAR
});
return E2307Details;
}

变化:

• 我删除了AsEnumerable，以便在数据库中执行WHERE
• 然后添加了一个ToListAsync，异步获取所有匹配记录
• 在前面的表达式周围额外的一对()，以便选择在列表上工作，而不是在任务上(它不起作用)

评论

• 现在每条记录调用GetUploadFileDetails(x.UL_ID)三次。这是可以优化的。
• 你可能想在查询的末尾添加另一个.ToList()。