如何将正常的foreach循环转换为c＃中的lambda表达式？

本文介绍了如何将正常的foreach循环转换为c＃中的lambda表达式？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 •public static Collection < SalesPlan > GetCurrentPlan（PurchasePlanRequest purchasePlanRequest） { SalesCustomerManager salesCustomerManager = new SalesCustomerManager（）; SalesCustomer salesCustomer = new SalesCustomer（）; salesCustomer.ReportingCustomerNumber = purchasePlanRequest.ReportingCustomerId; 集合< SalesPlan > salesPlanCollection = new Collection < SalesPlan > （）; salesCustomer = salesCustomerManager.GetCustomerLinesPlansCoverages（salesCustomer）; 集合< SalesPlan > renewalPlan = new Collection < SalesPlan > （）; 集合< SalesPlan > currentPlan = new Collection < SalesPlan > （）; foreach（SalesLineOfBusiness lob in salesCustomer.SalesLineOfBusinessCollection） { if（lob.LineOfBusinessCode == purchasePlanRequest.LOBCode） { foreach（SalesPlan salepln in lob.SalesPlanCollection） { //比较PlanEffectiveDate等于CurrentRenewalDate。 if（purchasePlanRequest.PlanEffectiveDate == currentRenewalDate） { if（salepln.IsRenewalPlan == true） { currentPlan.Add（salepln）; } } 其他 { if（salepln.IsCurrentPlan == true） { currentPlan.Add（salepln）; } } } } } return currentPlan; } 在粗体代码foreach循环中，我想使用Lambda表达式而不是Foreach循环。 任何人都可以建议我这样做...。 解决方案 你可以使用LINQ在集合上运行循环，如下所示 - lob.SalesPlanCollection.ForEach（i => i.DoStuff（））; 我的第一个问题是为什么？你想把它转换成Lambda吗？因为我个人没有看到代码有什么问题 但要回答你的问题; lob.SalesPLanCollection.ForEach（i = > { / / 比较PlanEffectiveDate等于CurrentRenewalDate。 if （purchasePlanRequest.PlanEffectiveDate = = currentRenewalDate） { if （salepln.IsRenewalPlan == true ） { currentPlan.Add（salepln）; } else { if （salepln.IsCurrentPlan == true ） { currentPlan.Add（salepln） ; } } } }）; 您可以在表达式中添加Where子句，以限制迭代的数据量... public static Collection< salesplan> GetCurrentPlan（PurchasePlanRequest purchasePlanRequest） { SalesCustomerManager salesCustomerManager = new SalesCustomerManager（）; SalesCustomer salesCustomer = new SalesCustomer（）; salesCustomer.ReportingCustomerNumber = purchasePlanRequest.ReportingCustomerId; Collection< salesplan> salesPlanCollection = new Collection< salesplan>（）; salesCustomer = salesCustomerManager.GetCustomerLinesPlansCoverages（salesCustomer）; Collection< salesplan> renewalPlan = new Collection< salesplan>（）; Collection< salesplan> currentPlan = new Collection< salesplan>（）; foreach（SalesLineOfBusiness lob in salesCustomer.SalesLineOfBusinessCollection.Where（o => o.LineOfBusinessCode == purchasePlanRequest.LOBCode）） { lob.SalesPLanCollection.ForEach（i = > { //比较PlanEffectiveDate等于CurrentRenewalDate。 if（purchasePlanRequest.PlanEffectiveDate == currentRenewalDate） { if（salepln.IsRenewalPlan == true） ） { currentPlan.Add（salepln）; } else { if（salepln.IsCurrentPlan == true） { currentPlan.Add（salepln）; } } } }）; } return currentPlan; }< / salesplan>< / salesplan>< / salesplan>< / salesplan>< / salesplan>< / salesplan>< / salesplan> • public static Collection<SalesPlan> GetCurrentPlan(PurchasePlanRequest purchasePlanRequest) { SalesCustomerManager salesCustomerManager = new SalesCustomerManager(); SalesCustomer salesCustomer = new SalesCustomer(); salesCustomer.ReportingCustomerNumber = purchasePlanRequest.ReportingCustomerId; Collection<SalesPlan> salesPlanCollection = new Collection<SalesPlan>(); salesCustomer = salesCustomerManager.GetCustomerLinesPlansCoverages(salesCustomer); Collection<SalesPlan> renewalPlan = new Collection<SalesPlan>(); Collection<SalesPlan> currentPlan = new Collection<SalesPlan>(); foreach (SalesLineOfBusiness lob in salesCustomer.SalesLineOfBusinessCollection) { if (lob.LineOfBusinessCode == purchasePlanRequest.LOBCode) { foreach (SalesPlan salepln in lob.SalesPlanCollection) { //Compare PlanEffectiveDate is equal to CurrentRenewalDate. if (purchasePlanRequest.PlanEffectiveDate == currentRenewalDate) { if (salepln.IsRenewalPlan == true) { currentPlan.Add(salepln); } } else { if (salepln.IsCurrentPlan == true) { currentPlan.Add(salepln); } } } } } return currentPlan; }In the bold code foreach loop, I want to use Lambda expression instead of Foreach loop.Can anybody suggest me approach of doing so…. 解决方案 You can run a loop over a collection using LINQ as below -lob.SalesPlanCollection.ForEach(i => i.DoStuff());My first question would be WHY? would you want to convert it too Lambda? As I personally dont see anything wrong with the codebut to answer your question;lob.SalesPLanCollection.ForEach(i =>{ //Compare PlanEffectiveDate is equal to CurrentRenewalDate. if (purchasePlanRequest.PlanEffectiveDate == currentRenewalDate) { if (salepln.IsRenewalPlan == true) { currentPlan.Add(salepln); } else { if (salepln.IsCurrentPlan == true) { currentPlan.Add(salepln); } } }});You can add a Where clause to your expression to limit the amount of data being iterated over as well...public static Collection<salesplan> GetCurrentPlan(PurchasePlanRequest purchasePlanRequest) { SalesCustomerManager salesCustomerManager = new SalesCustomerManager(); SalesCustomer salesCustomer = new SalesCustomer(); salesCustomer.ReportingCustomerNumber = purchasePlanRequest.ReportingCustomerId; Collection<salesplan> salesPlanCollection = new Collection<salesplan>(); salesCustomer = salesCustomerManager.GetCustomerLinesPlansCoverages(salesCustomer); Collection<salesplan> renewalPlan = new Collection<salesplan>(); Collection<salesplan> currentPlan = new Collection<salesplan>(); foreach (SalesLineOfBusiness lob in salesCustomer.SalesLineOfBusinessCollection.Where(o => o.LineOfBusinessCode == purchasePlanRequest.LOBCode)) { lob.SalesPLanCollection.ForEach(i => { //Compare PlanEffectiveDate is equal to CurrentRenewalDate. if (purchasePlanRequest.PlanEffectiveDate == currentRenewalDate) { if (salepln.IsRenewalPlan == true) { currentPlan.Add(salepln); } else { if (salepln.IsCurrentPlan == true) { currentPlan.Add(salepln); } } } }); } return currentPlan; }</salesplan></salesplan></salesplan></salesplan></salesplan></salesplan></salesplan> 这篇关于如何将正常的foreach循环转换为c＃中的lambda表达式？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！