動態/有條件地將多個LINQ的GroupBy

Question

我有提供

列

操作（總和（幾乎相同的柱組的兩個表之間的選擇）的

1. 表類型用戶選擇的用戶接口，平均值，中位數等）
2. 的GroupBy選項（一堆複選框）

我打算創建retur的方法ns結果集基於用戶選擇，雖然我認爲我通過了其他一切（除了表選擇），但我堅持如何使用GroupBy（或任何其他方式）通過一個接一個的子句構建組。

這是現在讓我想回到使用一個簡單的SQL字符串生成來做到這一點的唯一的東西。

這裏是我到目前爲止的代碼：

public IQueryable<ACSImpactAnalysisModel> GetDataForReport(TableType table, uint year,  OpType operation, uint groupOptions, uint measures) 
    { 
     var dataContext = new ACSImpactEntities(); 

     var discharges = from p in dataContext.ACSNationals 
         select new 
         { 
          p.YEAR, 
          p.AGE, 
          p.FEMALE, 
          p.RACE, 
          p.ASOURCE, 
          p.PAY1, 
          LOS = p.LOS > 0 ? p.LOS : 0, 
          CHG = p.TOTCHG > 0 ? p.TOTCHG : 0, 
          NPR = p.NPR > 0 ? p.NPR : 0, 
          DIS_STS = p.DISPUB04 > 0 ? p.DISPUB04 : 0 
         }; 

     //if (table == TableType.states) 
     // discharges = from p in dataContext.ACSStates 
     //     select p; 


     List<int> years = new List<int>(); 
     if ((year & Constants.YEAR2008) == Constants.YEAR2008) years.Add(2008); 
     if ((year & Constants.YEAR2009) == Constants.YEAR2009) years.Add(2009); 

     discharges = discharges.Where(a => years.Any(b => a.YEAR == b)); 

     if ((groupOptions & Constants.SEX) == Constants.SEX) 
      discharges = discharges.Where(a => a.FEMALE > 0); 

     if ((groupOptions & Constants.RACE) == Constants.RACE) 
      discharges = discharges.Where(a => a.RACE > 0); 

     if ((groupOptions & Constants.ER_ADMISSION) == Constants.ER_ADMISSION) 
      discharges = discharges.Where(a => a.ASOURCE > 0); 

     if ((groupOptions & Constants.PAYER_TYPE) == Constants.PAYER_TYPE) 
      discharges = discharges.Where(a => a.PAY1 > 0); 

     var analysis = from a in discharges 
         select new 
         { 
          AGE_GROUP = 
          (
           a.AGE >= 18 && a.AGE <= 44 ? "18-44" : 
           a.AGE >= 45 && a.AGE <= 54 ? "45-54" : 
           a.AGE >= 55 && a.AGE <= 64 ? "55-64" : ">= 65" 
          ), 
          SEX = (a.FEMALE == 1 ? "FEMALE" : "MALE"), 
          RACE = 
          (
           a.RACE == 1 ? "WHITE" : 
           a.RACE == 2 ? "BLACK" : 
           a.RACE == 3 ? "HISPANIC" : 
           a.RACE == 4 ? "ASIAN OR PACIFIC ISLANDER" : 
           a.RACE == 5 ? "NATIVE AMERICAN" : 
           a.RACE == 6 ? "OTHER" : "" 
          ), 
          ASOURCE = (a.ASOURCE == 1 ? "ER" : "NON ER"), 
          PAY1 = 
          (
           a.PAY1 == 1 ? "MEDICARE" : 
           a.PAY1 == 2 ? "MEDICAID" : 
           a.PAY1 == 3 ? "PRIVATE INCLUDE HMO" : 
           a.PAY1 == 4 ? "SELF PAY" : 
           a.PAY1 == 5 ? "NO CHARGE" : 
           a.PAY1 == 6 ? "OTHER" : "" 
          ), 
          a.YEAR, 
          a.FEMALE, 
          a.LOS, 
          a.CHG, 
          a.NPR, 
          a.DIS_STS 
         }; 

     var grouped_analysis = analysis.GroupBy(groups => groups.YEAR); 

     //These lines generate error, but this is something what I want to be able to do 
     if ((groupOptions & Constants.AGE_GROUP) == Constants.AGE_GROUP) 
      grouped_analysis = analysis.GroupBy(age_group => age_group.AGE_GROUP); 

     if ((groupOptions & Constants.ASOURCE) == Constants.ASOURCE) 
      grouped_analysis = analysis.GroupBy(asource => asource.ASOURCE); 


     return analysis; 
    } 

Answer 1

您可以使用Dynamic Linq，你可能還需要Predicate Builder。