我該怎么做才能讓這個循環運行得更快？ private void accessVendorGridData() { try { foreach (var item in getAllVendorList) { item.CurrencyName = "USD"; // Fetch Addresses in Vendor Grid var Addr = _vendorservice.GetAllVendorAdd().Where(x => x.vendorId == item.Id).ToList(); if (Addr.Count > 0) { item.VendorAddressLine = String.Format("{0}, {1}, {2}, {3}, {4}", Addr[0].Address, Addr[0].City, Addr[0].StateProvince, Addr[0].ZipPostalCode, Addr[0].CountryRegion); } // Fetch Payment terms in Vendor Grid var paymentTerm = _vendorservice.GetAllPaymentTerms().Where(x => x.Id == item.PaymentTermId).ToList().SingleOrDefault(); if (paymentTerm != null) { item.paymenttermitem = paymentTerm.Name; } // Fetch Tax Scheme in Vendor Grid var taxscheme = _vendorservice.GetAllTaxScheme().Where(x => x.Id == item.TaxschemeId).ToList().SingleOrDefault(); if (taxscheme != null) { item.TaxschemeName = taxscheme.TaxSchemaName; } } } catch (Exception ex) { _exLog.AddErrorLog(ex, "NewVendor, accessVendorGridData()"); ModernDialog.ShowMessage(ex.Message, "Error!", MessageBoxButton.OK); } }我該怎么做才能讓這個循環運行得更快？我嘗試了 Parallel.ForEach 但在中間迷失了。有人可以幫忙嗎？
1 回答
jeck貓
TA貢獻1909條經驗 獲得超7個贊
您可以從循環中提取,作為字典，而不是在每次迭代時查詢：vendorspaymentTermsallTaxSchemes
private void accessVendorGridData() {
var vendors = _vendorservice
.GetAllVendorAdd()
.GroupBy(item => item.Id)
.ToDictionary(chunk => chunk.Key, chunk => chunk.ToList());
var paymentTerms = _vendorservice
.GetAllPaymentTerms()
.GroupBy(item => item.Id)
.ToDictionary(chunk => chunk.Key, chunk => chunk.SingleOrDefault());
var allTaxSchemes = _vendorservice
.GetAllTaxScheme()
.GroupBy(item => item.Id)
.ToDictionary(chunk => chunk.Key, chunk => chunk.SingleOrDefault());
foreach (var item in getAllVendorList) {
var Addr = vendors.TryGetValue(item.Id, out var addrs)
? addrs
: new List<Vendor>(); //TODO: put the right type instead of Vendor
var paymentTerm = paymentTerms.TryGetValue(item.PaymentTermId, out var term)
? term
: null;
var taxscheme = allTaxSchemes.TryGetValue(item.PaymentTermId, out var scheme)
? scheme
: null;
}
}
您當前的代碼有
O(|getAllVendorList| * (|vendors| + |paymentTerms| + |allTaxSchemes|))
時間復雜度，這個有
O(|getAllVendorList| + |vendors| + |paymentTerms| + |allTaxSchemes|)
_vendorservice.GetXXX()但是，如果是對服務、RDBMS 等的查詢，那么它不是一個解決方案，并且您必須在每次迭代時調用它（因為數據可以更改）
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