摘要:LINQ To SQL IN 與排序
承上篇,讀者繼續詢問排序問題,如要依IN時傳入元素的順序排列,該如何做?
C#
using System; 
using 
using System.Collections.Generic; using System.Linq; using System.Text; 
using System.Data.Linq; namespace ConsoleApplication36 { 
class Program 
{ 
static void Main(string[] args) { DataClasses1DataContext context = new DataClasses1DataContext(); context.Log = Console.Out; var result = from s1 in context.Customers where (new string[] { "UK", "Lisboa" }).Contains(s1.City) select s1; var result2 = CustomSort(result.ToList(), new string[] { "UK", "Lisboa" }); foreach (var item in result2) { Console.WriteLine(item.City); 
} Console.ReadLine(); } static List<Customers> CustomSort(List<Customers> list,string[] citys) { List<Customers> result = new List<Customers>(); foreach (var item in citys) { var query = from s1 in list where s1.City == item select s1; foreach (var ditem in query) result.Add(ditem); } return result; } } }
VB.NET
01 Module Module1
02
03 Sub Main()
04
05 Dim context As New DataClasses1DataContext()
06
07 Dim lists = From s1 In context.Customers Where (New String() {"UK", "Lisboa"}).Contains(s1.City) Select s1
08 For Each item In CustomSort(lists.ToList(), New String() {"UK", "Lisboa"})
09 Console.WriteLine(item.City)
10 Next
11 Console.ReadLine()
12 End Sub
13
14 Function CustomSort(ByVal source As List(Of Customers), ByVal citys As String())
15 Dim result As New List(Of Customers)
16 For Each item In citys
17 Dim localItem = item
18 Dim query = From s1 In source Where s1.City = localItem Select s1
19 For Each ditem In query
20 result.Add(ditem)
21 Next
22 Next
23 Return result
24 End Function
25
26End Module
Module Module1 02
03
Sub Main() 04
05
Dim context As New DataClasses1DataContext() 06
07
Dim lists = From s1 In context.Customers Where (New String() {"UK", "Lisboa"}).Contains(s1.City) Select s1 08
For Each item In CustomSort(lists.ToList(), New String() {"UK", "Lisboa"}) 09
Console.WriteLine(item.City) 10
Next 11
Console.ReadLine() 12
End Sub 13
14
Function CustomSort(ByVal source As List(Of Customers), ByVal citys As String()) 15
Dim result As New List(Of Customers) 16
For Each item In citys 17
Dim localItem = item 18
Dim query = From s1 In source Where s1.City = localItem Select s1 19
For Each ditem In query 20
result.Add(ditem) 21
Next 22
Next 23
Return result 24
End Function 25
26
End Module
請注意,ToList後就已成為離線模式,接下來的CustomSort不會送出任何SQL指令.
