從SourceB獲取任何元素在SourceA中的ID

Question

我一直在試圖構建兩個不同的數據庫中的兩個模型可能看起來像一個奇怪的加入方法，你可以查詢第一個，然後返回ID的小列表進行搜索另一個分貝。一切工作正常吧一個或兩個東西，我不能做Id列表子查詢使用lambda函數，我有Id選擇器功能，鏈接了通用但在where子句現在將工作，因爲我不知道誰鏈接源類型對象爲Id的傳遞函數，所以.Where(TSource => idlist.Contains(Idselector)示例代碼由於List.Conatins代碼而低於最大值。如果有人可以幫助將不勝感激，因爲我stook

public static Foo JoinTwoModels<T1,T2>(
      DbSet Dbs1, 
      DbSet Dbs2, 
      Expression<Func<T1, object>> Id1, 
      Expression<Func<T1, dynamic>> Selector1, 
      Expression<Func<T1, bool>> Search1, 
      Expression<Func<T2, object>> Id2, 
      Expression<Func<T2, dynamic>> Selector2) 
     { 
      var Output1 = Queryable.OfType<T1>(Dbs1); 

      var Output2 = Queryable.OfType<T2>(Dbs2); 

      List<dynamic> Result1 = Output1.Where(Search1).Select(Selector1).ToList(); 

      List<object> idList = new List<object>(); 

      PropertyInfo p1 = Result1[0].GetType().GetProperty("Id"); 

      foreach (var o1 in Result1) 
      { 
       idList.Add(p1.GetValue(o1)); 
      } 

      //Query result entries into db 
      List<T2> Result2 = Output2.Where(idlist.contains(Id2)).ToList(); 

Answer 1

怎麼是這樣的：

public class Foo 
{ 
    public int Context; 
    public string Data; 
} 

public class Bar 
{ 
    public int Context; 
    public string Data; 
} 

public static IEnumerable<TOutput> JoinTwoModels<T1, T2, TIdent, TOutput>(
    IEnumerable<T1> sourceA, 
    IEnumerable<T2> sourceB, 
    Func<T1, TIdent> idSelectorA, 
    Func<T2, TIdent> idSelectorB, 
    Func<T1, TOutput> selectorA, 
    Func<T2, TOutput> selectorB) 
{ 

    var quearyA = sourceA 
      .Select(x => new {Value = selectorA(x),Id = idSelectorA(x)}); 

    var quearyB = sourceB 
      .Select(y => new {Value = selectorB(y),Id = idSelectorB(y)}) 
      .Where(y => quearyA.Select(x => x.Id).Contains(y.Id)) 
      .Select(y => y.Value); 


    return quearyA.Select(x => x.Value).Concat(quearyB); 
} 

private static void Main(string[] args) 
{ 
    var sourceA = new List<Foo>() {new Foo() {Context = 2, Data = "I'm a Foo"}}; 
    var sourceB = new List<Bar>() {new Bar() {Context = 2, Data = "I'm a Bar"}}; 

    var Output1 = sourceA.AsQueryable(); 
    var Output2 = sourceB.AsQueryable(); 

    var results = JoinTwoModels(
     Output1, 
     Output2, 
     (Func<Foo, int>) (x => x.Context), 
     (Func<Bar, int>) (x => x.Context), 
     (Func<Foo, string>) (x => x.Data), 
     (Func<Bar, string>) (x => x.Data)); 

    foreach (var item in results) 
     Console.WriteLine(item); 
} 

你想不太清楚是什麼;所以上面我選擇了Source-A（類型爲Foo）和Source-B（類型爲Bar）共享一個公共Context（id）的所有項目，並以轉換後的公共類型返回它們。

可以簡化下來，如果你只是想從B值，到：

var quearyA = sourceA.Select(idSelectorA); 

var quearyB = sourceB 
     .Select(y => new {Value = selectorB(y),Id = idSelectorB(y)}) 
     .Where(y => quearyA.Select(x => x).Contains(y.Id)) 
     .Select(y => y.Value); 

return quearyB;