[英]C# compare two Lists and update it's column values
我有兩個C#列表(列表listA和列表listB),如何比較這兩個列表,如果發現重復(特定列,例如ID_num和ID_cust),則更新列“ ID_duplicate”,它是listB列ID的值。
DataSet ds = subMain;
List<string> listA = (from r in ds.Tables[0].AsEnumerable()
Select r.Field<string>("ID_num") +
r.Field<string>("ID_cust")).ToList();
DataSet dsMain = Mains;
List<string> listB = (from r in dsMain.Tables[0].AsEnumerable()
select r.Field<string>("ID_num") +
r.Field<string>("ID_cust")).ToList();
我想這listA
將包含新列ID_duplicate
與價值ID_num
從listB
。
這樣,重復項將以某種方式與此ID_num
鏈接。
然后,我將該ID_duplicate
更新為數據庫。
編輯:在注釋下面添加了更多解釋。
如果我了解是加入:
var listA = new List<Row> {
new Row { ID= 1, IdNum = 1, IdCust = 1 },
new Row { ID= 2, IdNum = 1, IdCust = 2 },
new Row { ID= 3, IdNum = 2, IdCust = 1 },
new Row { ID= 4, IdNum = 1, IdCust = 3 },
new Row { ID= 5, IdNum = 3, IdCust = 1 },
new Row { ID= 6, IdNum = 4, IdCust = 1 }
};
var listB = new List<Row> {
new Row { ID= 1, IdNum = 5, IdCust = 1 },
new Row { ID= 5, IdNum = 6, IdCust = 2 },
new Row { ID= 7, IdNum = 2, IdCust = 1 },
new Row { ID= 9, IdNum = 1, IdCust = 3 },
new Row { ID= 11, IdNum = 7, IdCust = 2 }
};
var t = (from a in listA
join b in listB on a.IdCust.ToString() + a.IdNum.ToString()
equals
b.IdCust.ToString() + b.IdNum.ToString()
select new
{
ID = a.ID,
IdUpdate = b.ID
}).ToArray();
foreach (var item in t)
{
Console.WriteLine("ID {0} IdUpdate {1}", item.ID, item.IdUpdate);
}
這是Row類
class Row
{
public int ID { get; set; }
public int IdNum { get; set; }
public int IdCust { get; set; }
}
顯然,您可以像這樣在Row類上創建一個計算列
public string ValueToCompare
{
get
{
return this.IdNum.ToString() + this.IdCust.ToString();
}
}
並在連接時使用它進行比較
最高
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