在C#Linq中使用訂單條件合并2個不同的串列-有解無憂

所以我想從 2 個不同的串列中加入而沒有任何鍵并排序列出一些條件。

我有Class這樣的：

public class DataA
{
    public string Data { get; set; }
    public int Order { get; set; }
    public DateTime CreatedOn { get; set; }
}

public class DataB
{
    public string Data { get; set; }
    public int Order { get; set; }
    public DateTime CreatedOn { get; set; }
}

和這樣的清單：

var listDataA = new List<DataA> 
{ 
    new DataA { Data = "data a 1", Order = 1, CreatedOn = new DateTime(2020, 11, 12, 00, 00, 00) },
    new DataA { Data = "data a 2", Order = 2, CreatedOn = new DateTime(2020, 11, 13, 00, 00, 00) },
    new DataA { Data = "data a 5", Order = 5, CreatedOn = new DateTime(2020, 11, 14, 16, 00, 00) },
    new DataA { Data = "data a 6", Order = 6, CreatedOn = new DateTime(2020, 11, 15, 00, 00, 00) },
    new DataA { Data = "data a 7", Order = 7, CreatedOn = new DateTime(2020, 11, 16, 00, 00, 00) }
};

var listDataB = new List<DataB> 
{
    new DataB { Data = "data b 5", Order = 5, CreatedOn = new DateTime(2020, 11, 14, 14, 00, 00) },
    new DataB { Data = "data b 8", Order = 8, CreatedOn = new DateTime(2020, 11, 16, 00, 00, 00) }
};

我想從其他Order屬性中訂購串列，如果Order值相同，它將檢查CreatedOn屬性。所以資料看起來像這樣：

[
    { Data = "data a 1", Order = 1, CreatedOn = new DateTime(2020, 11, 12, 00, 00, 00) },
    { Data = "data a 2", Order = 2, CreatedOn = new DateTime(2020, 11, 13, 00, 00, 00) },
    { Data = "data b 5", Order = 5, CreatedOn = new DateTime(2020, 11, 14, 14, 00, 00) },
    { Data = "data a 5", Order = 5, CreatedOn = new DateTime(2020, 11, 14, 16, 00, 00) },
    { Data = "data a 6", Order = 6, CreatedOn = new DateTime(2020, 11, 15, 00, 00, 00) },
    { Data = "data a 7", Order = 7, CreatedOn = new DateTime(2020, 11, 16, 00, 00, 00) },
    { Data = "data b 8", Order = 8, CreatedOn = new DateTime(2020, 11, 16, 00, 00, 00) }
]

我怎樣才能在 Linq 中做到這一點？

uj5u.com熱心網友回復：

真的，我認為你最好為這些類定義一個介面，其中提到你想要使用的公共部分

interface IDataX
{
   int Order { get; set; }
   DateTime CreatedOn { get; set; }
}

public class DataA: IDataX ...

public class DataB: IDataX ...

那么你可以這樣做

var output = listDataA.Cast<IDataX>().Concat(listDataB).OrderBy(d => d.Order).ThenBy(d => d.CreatedOn);

由于 Data 對兩者都是通用的，您也可以將其添加到介面中，然后您可以使用來自 IDataX 的資料，而無需具體知道下面的物件是 DataA 還是 DataB。

如果您反對這一點（并且也反對為 A/B 建立一個具有共同屬性 Order/Created..此處呈現的不是為了示例）：

class Holder{
   public int Order { get; set; }
   public DateTime CreatedOn { get; set; }

   public object OriginalData { get; set; }
}

和連續預測..

listA
  .Select(a => new Holder { Order = a.Order, CreatedOn = a.CreatedOn, OriginalData = a})
  .Concat(
     listB.Select(b => new Holder { Order = b.Order, CreatedOn = b.CreatedOn, OriginalData = b})
  ).OrderBy(x => x.Order).ThenBy(x => x.CreatedOn)

..then cast back the OriginalDatawhen you want to use it..（if(x.OriginalData is DataA a) ... else if(x.OriginalData is DataB b)這有點..呃）

就個人而言，我肯定會為此利用某種多型性

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標籤：C＃林克

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