燃燒吧~~ObjectDataSouce配合物件導向的設計方式連結資料 VB.NET

2008-08-05

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ADO.NET
2008-09-21

這一篇的靈感來自於Topcat -->ObjectDataSouce結合物件設計方式

進化版！

當然我們先假設

1.資料表越來越多 ... 能夠再把重複的地方抽離嗎？

2.依照Topcat的方式 ... 每產生一個 objEmployee 物件就要Select一次資料 ...好像對資料庫有點負擔 ..

基於以上兩點，作為開發的動力！

這一篇的靈感來自於Topcat -->ObjectDataSouce結合物件設計方式

進化版！

當然我們先假設

1.資料表越來越多 ... 能夠再把重複的地方抽離嗎？

2.依照Topcat的方式 ... 每產生一個 objEmployee 物件就要Select一次資料 ...好像對資料庫有點負擔 ..

基於以上兩點，作為開發的動力！

首先 ... 我們把增刪改三種方法抽離

寫成一個objADU 的類別(恩= =、我是取開頭 ... Add Del Update)

當然以下所使用到的objData 物件在之前的文章有提到過

參考如下-->ASP.NET 2.0抽離資料存取 & 連線字串-VB.NET

01 ''' <summary>
02 ''' 增刪改核心元件，資料存取層元件。 By Phoehix - 2008
03 ''' </summary>
04 ''' <remarks></remarks>
05

Public Class objADU
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Private oData As New objData()
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Protected Sub Add(ByRef SqlTxt As String, ByVal Parameter As SqlParameter)
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Try
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oData.SqlExecuteNonQuery(SqlTxt, Parameter)
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Catch ex As Exception
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Throw
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End Try
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End Sub
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Protected Sub Add(ByRef SqlTxt As String, ByVal Parameters As SqlParameter())
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Try
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oData.SqlExecuteNonQuery(SqlTxt, Parameters)
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Catch ex As Exception
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Throw
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End Try
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End Sub
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Protected Sub Del(ByRef SqlTxt As String, ByRef Parameter As SqlParameter)
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Try
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oData.SqlExecuteNonQuery(SqlTxt, Parameter)
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Catch ex As Exception
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Throw
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End Try
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End Sub
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Protected Sub Del(ByRef SqlTxt As String, ByRef Parameters As SqlParameter())
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Try
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oData.SqlExecuteNonQuery(SqlTxt, Parameters)
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Catch ex As Exception
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Throw
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End Try
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End Sub
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Protected Sub Update(ByRef SqlTxt As String, ByRef Parameter As SqlParameter)
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Try
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oData.SqlExecuteNonQuery(SqlTxt, Parameter)
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Catch ex As Exception
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Throw
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End Try
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End Sub
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Protected Sub Update(ByRef SqlTxt As String, ByRef Parameters As SqlParameter())
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Try
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oData.SqlExecuteNonQuery(SqlTxt, Parameters)
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Catch ex As Exception
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Throw
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End Try
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End Sub
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Public Sub New()
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End Sub
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Protected Overrides Sub Finalize()
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MyBase.Finalize()
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End Sub
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End Class

6-宣告一個 oData 物件為objData 順便做初始化

當然永續發展為考量 ... 增刪改這三種方法都用多載的方式 ...(傳入一個參數 OR 傳入多個參數)

8~21 執行 Add 傳入SQL字串和預存程序

22~35 執行 Del 傳入SQL字串和預存程序

36~49 執行 Update傳入SQL字串和預存程序

51~57 請自動省略 ...

再來我們以一個資料表做為範例 News 新聞公告，其他的靠自己~

資料表的設計如下：

N_ID 是新聞的編號自動遞增

N_Date 是發布日期

N_Subject 是新聞標題

N_Content 是新聞內容

以下是 objNews 的"物件模型"

001 ''' <summary>
002 ''' News 資料庫物件，資料存取層物件。 By Phoehix - 2008
003 ''' </summary>
004

Public Class objNews
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Inherits objADU
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''' <summary>
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''' 新聞公告編號
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''' </summary>
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Private _ID As Integer
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''' <summary>
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''' 發布時間
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''' </summary>
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''' <remarks></remarks>
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Private _Date As Date
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''' <summary>
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''' 標題欄位
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''' </summary>
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Private _Subject As String
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''' <summary>
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''' 內容欄位
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''' </summary>
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Private _Content As String
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''' <summary>
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''' 取得或設定新聞公告的編號(_ID)
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''' </summary>
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Public Property NewsID() As Integer
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Get
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Return _ID
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End Get
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Set(ByVal value As Integer)
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_ID = value
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End Set
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End Property
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''' <summary>
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''' 取得新聞公告發布時間(_Date)
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''' </summary>
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Public ReadOnly Property NewsDate() As Date
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Get
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Return _Date
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End Get
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End Property
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''' <summary>
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''' 取得或設定新聞公告的標題(_Subject)
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''' </summary>
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Public Property NewsSubject() As String
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Get
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Return _Subject
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End Get
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Set(ByVal value As String)
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_Subject = value
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End Set
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End Property
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''' <summary>
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''' 取得或設定新聞公告的內容(_Content)
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''' </summary>
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Public Property NewsContent() As String
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Get
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Return _Content
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End Get
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Set(ByVal value As String)
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_Content = value
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End Set
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End Property
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''' <summary>
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''' 初始化 objNews 類別的新執行個體
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''' </summary>
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Public Sub New()
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070

End Sub
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''' <param name="row"> DataRow。</param>
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Public Sub New(ByRef row As DataRow)
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GetNews(row)
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End Sub
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Private Sub GetNews(ByRef row As DataRow)
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Try
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_ID = Integer.Parse(row(0).ToString())
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_Date = Date.Parse(row(1).ToString())
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_Subject = row(2).ToString()
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_Content = row(3).ToString()
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Catch ex As Exception
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Throw New Exception(ex.Message)
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End Try
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End Sub
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''' <summary>
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''' 新增一筆消息
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''' </summary>
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Public Overloads Sub Add()
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Try
090

091

Dim SqlTxt As String = "INSERT INTO [News] ([N_Subject], [N_Content]) VALUES (@N_Subject, @N_Content)"
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Dim Parameters(1) As SqlParameter
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Parameters(0) = New SqlParameter("@N_Subject", _Subject)
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Parameters(1) = New SqlParameter("@N_Content", _Content)
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Add(SqlTxt, Parameters)
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Catch ex As Exception
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Throw New Exception(ex.Message)
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End Try
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End Sub
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''' <summary>
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''' 刪除一筆消息
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''' </summary>
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Public Overloads Sub Del()
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Try
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Dim SqlTxt As String = "Delete [News] WHERE ([N_ID] = @Original_N_ID)"
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'Original
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Dim Parameter As SqlParameter = New SqlParameter("@Original_N_ID", _ID)
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Del(SqlTxt, Parameter)
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Catch ex As Exception
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Throw New Exception(ex.Message)
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End Try
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End Sub
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''' <summary>
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''' 修改單筆消息
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''' </summary>
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Public Overloads Sub Update()
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Try
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Dim SqlTxt As String = "UPDATE News SET N_Subject = @N_Subject, N_Content = @N_Content WHERE N_ID = @Original_N_ID"
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Dim Parameters(2) As SqlParameter
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'New Set
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Parameters(0) = New SqlParameter("@N_Subject", _Subject)
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Parameters(1) = New SqlParameter("@N_Content", _Content)
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'Original
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Parameters(2) = New SqlParameter("@Original_N_ID", _ID)
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Update(SqlTxt, Parameters)
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Catch ex As Exception
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Throw New Exception(ex.Message)
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End Try
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End Sub
131

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Protected Overrides Sub Finalize()
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MyBase.Finalize()
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End Sub
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End Class

首先

再第五行的地方繼承objADU (真的吃撐了= = 分離出來多寫好多哈)

再來前面的部份都跟TopCat設計的類似

只有在 72~74的地方本來是傳 ID過來換成傳遞row過來

然後再75~84的部份由傳入的row 提取資料

再來88~130的部份 Add,Del,Update 改為 Overloads 因為繼承自objADU 已經有相同名稱的方法了

裡面就是把 SqlTxt 和 Parameter(預存程序) 丟給objADU 執行相對應的 Add,Del,Update

再來是配合ObjectDataSouce的物件，進行新增、修改、刪除、查詢的動作. 也可以把它當作 BLL層 ...

01 ''' <summary>
02 ''' News 資料庫，商業邏輯層物件。 By Phoehix - 2008
03 ''' </summary>
04

Public Class daoNews
05

''' <summary>
06

''' 取得News物件集合
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''' </summary>
08

''' <returns>List(Of DAL.objNews)</returns>
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Public Function GetNews() As List(Of DAL.objNews)
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Try
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Dim rNews As New List(Of DAL.objNews)
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rNews.Clear()
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Dim oData As New DAL.objData()
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Dim SqlTxt As String = "SELECT * From [News] ORDER BY [N_Date] DESC"
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Dim dt As New DataTable
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If oData.SqlSelectQuery(SqlTxt, dt) Then
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For Each row As DataRow In dt.Rows
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rNews.Add(New DAL.objNews(row))
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Next
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End If
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Return rNews
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Catch ex As Exception
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Throw New Exception(ex.Message)
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End Try
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End Function
26

''' <param name="NID">新聞公告編號</param>
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''' <returns></returns>
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''' <remarks></remarks>
29

Public Function GetNews(ByVal NID As Integer) As List(Of DAL.objNews)
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Try
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Dim rNews As New List(Of DAL.objNews)
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rNews.Clear()
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Dim oData As New DAL.objData()
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Dim SqlTxt As String = "SELECT * From [News] WHERE N_ID = @N_ID"
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Dim dt As New DataTable
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Dim Parameter As SqlParameter = New SqlParameter("@N_ID", NID)
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If oData.SqlSelectQuery(SqlTxt, Parameter, dt) Then
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rNews.Add(New DAL.objNews(dt.Rows(0)))
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End If
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Return rNews
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Catch ex As Exception
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Throw New Exception(ex.Message)
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End Try
44

End Function
45

Public Sub NewsUpdate(ByVal oNews As DAL.objNews)
47

Try
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oNews.Update()
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Catch ex As Exception
50

Throw New Exception(ex.Message)
51

End Try
52

End Sub
53

Public Sub NewsDel(ByVal oNews As DAL.objNews)
55

Try
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oNews.Del()
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Catch ex As Exception
58

Throw New Exception(ex.Message)
59

End Try
60

End Sub
61

Public Sub NewsAddNew(ByVal oNews As DAL.objNews)
63

Try
64

oNews.add()
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Catch ex As Exception
66

Throw New Exception(ex.Message)
67

End Try
68

End Sub
69

Public Sub New()
71

End Sub
73

Protected Overrides Sub Finalize()
75

MyBase.Finalize()
76

End Sub
77

End Class

和TopCat不同的地方在

16-把 SQL 和dt 傳過去給我們的objData類別把資料都填入dt 再傳回成功/失敗

17-For Each的方式把DT內的ROW 一一取出

18-把objNews 加入到物件集合中，把Row 傳遞過去這樣就可以減少對SQL Server的負擔了 ...

再來的程式碼都一樣 ... 比較值得一提的是

因為我把 objNews 寫成一個命名空間為DAL的類別庫(objConn,objData,objADU 也都是)

關於ObjectDataSource 在MSDN內有提到過這種方法 --> ObjectDataSource 強型別來源物件範例

以上

Phoenix 8/5

ASP.NET

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