加入&；使用LINQ转换多个列表

本文关键字：转换 列表 LINQ 使用 amp 加入 | 更新日期: 2023-09-27 18:22:09

Hi我有下面的代码，它会返回正确的数据，但似乎必须有更好的方法来组合3个列表，基于它们的公共字段，并使用LINQ将结果转换为给定类型的新列表，而不是在最后使用foreach。有什么想法吗？

  public IEnumerable<StagSummaryByCflHistoricalItem> GetSummaryByCflHistorical(DateTime currentDate)
  {
     var allRecords =
        this.preGrantSummaryHistoricalRepository
           .AllWithFetch(this.preGrantSummaryHistoricalRepository.All, x => x.CaseFileLocation)
           .Where(
           x => x.Date >= currentDate.FirstDayOfQuarterFromDateTime()
           && x.Date <= currentDate.LastDayOfQuarterFromDateTime())
           .ToList();
     var summaryForQuarter =
        allRecords.GroupBy(x => new { x.CaseFileLocation.Id, x.CaseFileLocation.Name }).Select(
           x =>
           new
              {
                 CaseFileLocationId = x.Key.Id,
                 Description = x.Key.Name,
                 TotalCasesEnteredCfl = x.Sum(y => y.TotalCasesEntered),
                 TotalNetFeeEnteredCfl = x.Sum(y => y.TotalNetFeeEntered),
                 TotalCasesLeftCfl = x.Sum(y => y.TotalCasesLeft),
                 TotalNetFeeLeftCfl = x.Sum(y => y.TotalNetFeeLeft)
              })
              .OrderBy(x => x.CaseFileLocationId)
              .ToList();
     var summaryForMonth =
        allRecords.Where(x => x.Date >= currentDate.FirstDayOfMonthFromDateTime())
        .GroupBy(x => new { x.CaseFileLocation.Id, x.CaseFileLocation.Name }).Select(
           x =>
           new
              {
                 CaseFileLocationId = x.Key.Id,
                 Description = x.Key.Name,
                 TotalCasesEnteredCfl = x.Sum(y => y.TotalCasesEntered),
                 TotalNetFeeEnteredCfl = x.Sum(y => y.TotalNetFeeEntered),
                 TotalCasesLeftCfl = x.Sum(y => y.TotalCasesLeft),
                 TotalNetFeeLeftCfl = x.Sum(y => y.TotalNetFeeLeft)
              })
              .OrderBy(x => x.CaseFileLocationId)
              .ToList();
     var summaryForWeek =
        allRecords.Where(x => x.Date >= currentDate.FirstDayOfWeekFromDateTime(DayOfWeek.Monday)).GroupBy(
           x => new { x.CaseFileLocation.Id, x.CaseFileLocation.Name }).Select(
              x =>
              new
                 {
                    CaseFileLocationId = x.Key.Id,
                    Description = x.Key.Name,
                    TotalCasesEnteredCfl = x.Sum(y => y.TotalCasesEntered),
                    TotalNetFeeEnteredCfl = x.Sum(y => y.TotalNetFeeEntered),
                    TotalCasesLeftCfl = x.Sum(y => y.TotalCasesLeft),
                    TotalNetFeeLeftCfl = x.Sum(y => y.TotalNetFeeLeft)
                 })
                 .OrderBy(x => x.CaseFileLocationId)
                 .ToList();
     var finalList = summaryForQuarter
        .Select(x => new StagSummaryByCflHistoricalItem()
           {
              CaseFileLocationId = x.CaseFileLocationId,
              Description = x.Description,
              QuarterTotalCasesEnteredCfl = x.TotalCasesEnteredCfl,
              QuarterTotalCasesLeftCfl = x.TotalCasesLeftCfl,
              QuarterTotalNetFeeEnteredCfl = x.TotalNetFeeEnteredCfl,
              QuarterTotalNetFeeLeftCfl = x.TotalNetFeeLeftCfl
           })
           .OrderBy(x => x.CaseFileLocationId)
           .ToList();
     foreach (var qrt in finalList)
     {
        var mnthData = summaryForMonth.FirstOrDefault(x => x.CaseFileLocationId == qrt.CaseFileLocationId);
        if (mnthData != null)
        {
           qrt.MonthTotalCasesEnteredCfl = mnthData.TotalCasesEnteredCfl;
           qrt.MonthTotalCasesLeftCfl = mnthData.TotalCasesLeftCfl;
           qrt.MonthTotalNetFeeEnteredCfl = mnthData.TotalNetFeeEnteredCfl;
           qrt.MonthTotalNetFeeLeftCfl = mnthData.TotalNetFeeLeftCfl;
        }
        var weekData = summaryForWeek.FirstOrDefault(x => x.CaseFileLocationId == qrt.CaseFileLocationId);
        if (weekData == null)
        {
           continue;
        }
        qrt.WeekTotalCasesEnteredCfl = weekData.TotalCasesEnteredCfl;
        qrt.WeekTotalCasesLeftCfl = weekData.TotalCasesLeftCfl;
        qrt.WeekTotalNetFeeEnteredCfl = weekData.TotalNetFeeEnteredCfl;
        qrt.WeekTotalNetFeeLeftCfl = weekData.TotalNetFeeLeftCfl;
     }
     return finalList;
  }

注意：我有意先将整个季度的数据作为一个列表，然后对其进行操作，以完成本月的工作；季度总数，但这主要是因为我无法从LINQ IQuerable组合中找到最终结果。

我使用的是NHibernate、LINQ方法语法、存储库模式和SQL Server 2008

加入&；使用LINQ转换多个列表

如果我正确阅读了您的代码，那么您将结果投影到具有相同结果成员的匿名类型，这使得将结果连接在一起非常容易。我最近在Union做了类似的事情。下面是我刚刚写的一个简化示例：

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
namespace ConsoleApplication1 {
    public class Month {
        public int MonthID { get; set; }
        public string MonthName { get; set; }
        public int NoDays { get; set; }
    }
    internal class Program {
        private static void Main(string[] args) {
            // Build up months
            var months = new List<Month>();
            for (var i = 1; i <= 12; i++) {
                months.Add(new Month {
                    MonthID = i,
                    MonthName = DateTimeFormatInfo.CurrentInfo.GetMonthName(i),
                    NoDays = DateTime.DaysInMonth(2012, i)
                });
            }
            var w = months.Select(m => new {
                m.MonthName
            });
            var x = months.Select(m => new {
                m.MonthName
            });
            var y = months.Select(m => new {
                m.MonthName
            });
            var z = w.Union(x).Union(y);
            foreach (var m in z) {
                Console.WriteLine(m.MonthName);
            }
            Console.Read();
        }
    }
}

请记住，"联合"（类似于SQLUNION子句）将从列表中删除任何重复项。如果您不想删除重复项（即执行"union all"），请按如下方式使用"Concat"：

var z = w.Concat(x).Concat(y);
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