Concat使用運算符來串連兩個序列。
運算符 Concat 是針對排序的多集所定義，其中接收者和自變數的順序相同。
在 SQL 中排序是產生結果之前的最後一個步驟。 基於這個理由， Concat 運算符是使用 UNION ALL 來實作，而且不會保留其自變數的順序。 若要確定結果中的排序正確，請務必明確排序結果。
範例 1
這個範例會使用 Concat 傳回所有 Customer 和 Employee 電話和傳真號碼的序列。
IQueryable<String> custQuery =
(from cust in db.Customers
select cust.Phone)
.Concat
(from cust in db.Customers
select cust.Fax)
.Concat
(from emp in db.Employees
select emp.HomePhone)
;
foreach (var custData in custQuery)
{
Console.WriteLine(custData);
}
Dim custQuery = _
(From c In db.Customers _
Select c.Phone) _
.Concat _
(From c In db.Customers _
Select c.Fax) _
.Concat _
(From e In db.Employees _
Select e.HomePhone)
For Each custData In custQuery
Console.WriteLine(custData)
Next
範例 2
這個範例會使用 Concat 傳回所有 Customer 和 Employee 名稱和電話號碼對應的序列。
var infoQuery =
(from cust in db.Customers
select new { Name = cust.CompanyName, cust.Phone }
)
.Concat
(from emp in db.Employees
select new
{
Name = emp.FirstName + " " + emp.LastName,
Phone = emp.HomePhone
}
);
foreach (var infoData in infoQuery)
{
Console.WriteLine("Name = {0}, Phone = {1}",
infoData.Name, infoData.Phone);
}
Dim infoQuery = _
(From cust In db.Customers _
Select Name = cust.CompanyName, Phone = cust.Phone) _
.Concat _
(From emp In db.Employees _
Select Name = emp.FirstName & " " & emp.LastName, _
Phone = emp.HomePhone)
For Each infoData In infoQuery
Console.WriteLine("Name = " & infoData.Name & _
", Phone = " & infoData.Phone)
Next