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トップDataSetに関する質問DataTableを片側外部結合したい（Left Joinのような）

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2

【追記２】追加

2017/11/24 08:58

投稿

退会済みユーザー
test CHANGED
@@ -16,7 +16,7 @@
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- 【追記】
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+ **【追記】**
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@@ -177,3 +177,343 @@
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  </html>
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  ```
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+
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+
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+
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+ **【追記２】**
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+
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+
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+ VB.NET に直したサンプルを下にアップしておきます。変換サービスで変換して動くように手直ししただけです。なので、VB.NET の書き方としてはアレかもしれませんが、期待通りの結果になることは確認済みです。
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+
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+
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+
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+
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+ ```
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+
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+ <%@ Page Language="VB" %>
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+
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+
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+
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+ <!DOCTYPE html>
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+
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+
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+
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+ <script runat="server">
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+
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+
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+
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+ Public Class Employee
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+
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+ Public Property Id() As String
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+
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+ Get
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+
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+ Return m_Id
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+
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+ End Get
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+
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+ Set
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+
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+ m_Id = Value
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+
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+ End Set
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+
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+ End Property
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+
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+ Private m_Id As String
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+
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+ Public Property Dept() As String
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+
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+ Get
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+
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+ Return m_Dept
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+
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+ End Get
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+
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+ Set
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+
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+ m_Dept = Value
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+
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+ End Set
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+
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+ End Property
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+
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+ Private m_Dept As String
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+
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+ Public Property Name() As String
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+
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+ Get
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+
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+ Return m_Name
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+
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+ End Get
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+
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+ Set
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+
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+ m_Name = Value
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+
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+ End Set
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+
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+ End Property
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+
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+ Private m_Name As String
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+
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+ End Class
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+
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+
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+
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+ Public Class Role
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+
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+ Public Property Id() As String
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+
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+ Get
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+
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+ Return m_Id
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+
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+ End Get
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+
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+ Set
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+ m_Id = Value
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+
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+ End Set
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+
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+ End Property
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+
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+ Private m_Id As String
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+
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+ Public Property Right() As String
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+
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+ Get
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+
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+ Return m_Right
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+
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+ End Get
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+
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+ Set
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+ m_Right = Value
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+
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+ End Set
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+
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+ End Property
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+
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+ Private m_Right As String
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+
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+ End Class
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+
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+
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+
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+ Public Class JoinedTable
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+ Public Property Id() As String
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+ Get
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+ Return m_Id
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+
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+ End Get
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+
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+ Set
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+
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+ m_Id = Value
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+
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+ End Set
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+
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+ End Property
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+
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+ Private m_Id As String
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+
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+ Public Property Dept() As String
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+
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+ Get
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+ Return m_Dept
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+
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+ End Get
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+
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+ Set
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+
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+ m_Dept = Value
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+
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+ End Set
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+
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+ End Property
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+
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+ Private m_Dept As String
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+
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+ Public Property Name() As String
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+
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+ Get
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+
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+ Return m_Name
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+
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+ End Get
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+
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+ Set
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+
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+ m_Name = Value
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+
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+ End Set
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+
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+ End Property
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+
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+ Private m_Name As String
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+
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+ Public Property Right() As String
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+
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+ Get
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+ Return m_Right
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+
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+ End Get
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+
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+ Set
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+ m_Right = Value
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+
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+ End Set
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+
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+ End Property
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+ Private m_Right As String
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+
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+ End Class
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+
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+
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+
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+
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+
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+ Protected Sub Page_Load(sender As Object, erg As EventArgs)
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+
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+ If Not IsPostBack Then
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+
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+ Dim employees As New List(Of Employee)() From {
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+
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+ New Employee() With {
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+
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+ .Id = "ID0001",
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+ .Dept = "部署A",
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+
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+ .Name = "鈴木太郎"
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+ },
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+ New Employee() With {
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+ .Id = "ID0002",
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+ .Dept = "部署A",
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+ .Name = "山田一郎"
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+
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+ },
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+
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+ New Employee() With {
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+
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+ .Id = "ID0003",
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+
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+ .Dept = "部署B",
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+
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+ .Name = "佐藤花子"
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+
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+ }
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+
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+ }
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+ Dim roles As New List(Of Role)() From {
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+
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+ New Role() With {
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+
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+ .Id = "ID0001",
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+
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+ .Right = "〇"
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+
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+ },
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+
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+ New Role() With {
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+
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+ .Id = "ID0003",
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+
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+ .Right = "×"
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+
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+ },
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+
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+ New Role() With {
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+
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+ .Id = "ID0004",
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+
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+ .Right = "〇"
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+
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+ }
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+
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+ }
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+ Dim query = From e In employees
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+ Group Join r In roles
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+ On e.Id Equals r.Id Into Group
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+ From subrole In Group.DefaultIfEmpty()
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+ Select New JoinedTable() With {
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+ .Id = e.Id,
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+ .Dept = e.Dept,
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+
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+ .Name = e.Name,
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+ .Right = If(subrole Is Nothing, String.Empty, subrole.Right)
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+
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+ }
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+
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+
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+
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+ GridView1.DataSource = query
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+
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+ GridView1.DataBind()
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+
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+ End If
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+
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+ End Sub
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+
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+ </script>
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+
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+
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+
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+ <html xmlns="http://www.w3.org/1999/xhtml">
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+
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+ <head runat="server">
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+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
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+ <title></title>
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+ </head>
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+ <body>
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+ <form id="form1" runat="server">
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+
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+ <div>
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+ <asp:GridView ID="GridView1" runat="server"></asp:GridView>
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+ </div>
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+ </form>
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+ </body>
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+ </html>
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+
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+ ```

1

サンプル追記

2017/11/24 08:58

投稿

退会済みユーザー
test CHANGED
@@ -13,3 +13,167 @@
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  左外部結合の実行
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  [https://docs.microsoft.com/ja-jp/dotnet/csharp/linq/perform-left-outer-joins](https://docs.microsoft.com/ja-jp/dotnet/csharp/linq/perform-left-outer-joins)
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+ 【追記】
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+ 上記案でのサンプルを書いておきます。Oracle の方は Entity Framework を使えれば簡単に、CSV の方も DataSet / DataTable を作るのよりは多分少ない労力で List<T> 型のオブジェクトを作れると思います。
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+
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+
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+
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+ ```
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+
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+ <%@ Page Language="C#" %>
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+
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+
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+
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+ <!DOCTYPE html>
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+
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+
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+
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+ <script runat="server">
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+
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+
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+
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+ public class Employee
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+
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+ {
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+
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+ public string Id { get; set; }
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+
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+ public string Dept { get; set; }
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+
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+ public string Name { get; set; }
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+
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+ }
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+
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+
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+
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+ public class Role
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+
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+ {
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+
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+ public string Id { get; set; }
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+
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+ public string Right { get; set; }
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+
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+ }
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+
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+
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+
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+ public class JoinedTable
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+
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+ {
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+
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+ public string Id { get; set; }
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+
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+ public string Dept { get; set; }
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+
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+ public string Name { get; set; }
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+
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+ public string Right { get; set; }
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+
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+ }
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+
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+
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+
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+ protected void Page_Load(object sender, EventArgs erg)
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+
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+ {
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+
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+ if (!IsPostBack)
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+
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+ {
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+
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+ List<Employee> employees = new List<Employee>()
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+
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+ {
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+
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+ new Employee() { Id = "ID0001", Dept = "部署A", Name = "鈴木太郎" },
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+
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+ new Employee() { Id = "ID0002", Dept = "部署A", Name = "山田一郎" },
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+
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+ new Employee() { Id = "ID0003", Dept = "部署B", Name = "佐藤花子" }
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+
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+ };
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+
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+
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+
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+ List<Role> roles = new List<Role>()
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+
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+ {
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+ new Role() { Id = "ID0001", Right ="〇" },
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+
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+ new Role() { Id = "ID0003", Right ="×" },
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+
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+ new Role() { Id = "ID0004", Right ="〇" }
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+
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+ };
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+
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+
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+
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+ var query = from e in employees
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+
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+ join r in roles on e.Id equals r.Id into gj
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+
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+ from sub in gj.DefaultIfEmpty()
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+
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+ select new JoinedTable
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+
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+ {
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+
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+ Id = e.Id,
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+
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+ Dept = e.Dept,
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+
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+ Name = e.Name,
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+
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+ Right = sub?.Right ?? string.Empty
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+
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+ };
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+
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+
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+
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+ GridView1.DataSource = query;
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+
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+ GridView1.DataBind();
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+
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+ }
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+
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+ }
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+
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+ </script>
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+
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+
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+
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+ <html xmlns="http://www.w3.org/1999/xhtml">
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+
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+ <head runat="server">
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+
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+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
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+
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+ <title></title>
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+
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+ </head>
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+
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+ <body>
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+
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+ <form id="form1" runat="server">
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+
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+ <div>
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+
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+ <asp:GridView ID="GridView1" runat="server"></asp:GridView>
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+
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+ </div>
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+
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+ </form>
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+
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+ </body>
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+
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+ </html>
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+
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+ ```