使用LINQ使用兩個鍵列加入兩個數據表

Question

數據表A：

Key1 | Key2 | A |乙

[1 1 ...]

[1 2 ...]

數據表B：

密鑰1 | Key2 | x | Ÿ

[11 ...]

[1 2]

期望的結果：

鍵1 | Key2 | A | B | X | ÿ

[1 1 ...]

[1 2 ...]

在最終的結果列A，B，X和Y已被添加到該新數據表。發生這種情況是因爲key1和key2在數據表A和B中都是相等的。如果給定條件 - （Key1和Key2是euqal），完全外部連接是可能的嗎？

Answer 1

var list1 = (from t1 in dataTable1.AsEnumerable() 
       select new 
       { 
        Key1 = t1.Field<int>("Key1"), 
        Key2 = t1.Field<int>("Key2"), 
        A = t1.Field<string>("A"), 
        B = t1.Field<string>("B") 
       }); 

var list2 = (from b in dataTable2.AsEnumerable() 
       select new 
       { 
        Key1 = b.Field<int>("Key1"), 
        Key2 = b.Field<int>("Key2"), 
        X = b.Field<string>("X"), 
        Y = b.Field<string>("Y") 
       }); 

// Now join the 2 collections and get the result you want. 

var result = (from x in list1 
       join y in list2 on new { x.Key1,x.Key2} equals new { y.Key1,y.Key2 } 
       select new { A = x.A, X = y.X }).ToList(); 

假設鍵1和鍵2是int型和A·B，X和Y是string型。

Answer 2

試試這個代碼的朋友：

var req = (from A in DatatableA 
     join B in DatatableB 
     on A.Key1 
      equals B.Key1 into DatatableResult 
      select new 
      { 
        Key1 = A.Key1 , 
       Key2 = A.Key2 , 
       A= A.A , 
       x= B.x , 
       y= B.y , 

      }).ToList();