#眉標=Silverlight、ADO.NET、Linq
#副標=Silverlight開發技術（13）
#大標=在Silverlight 2.0中使用ADO.NET Data Service
#作者=文／圖	董大偉



==<box>===========
程式1
Public Class WebDataService1
    '在Of的後面填入Data Model名稱：cNorthWindEntities
    Inherits DataService(Of cNorthWindEntities)
    ' 服務初始化設定
    Public Shared Sub InitializeService(ByVal config As IDataServiceConfiguration)
        ' 設定存取權限(『*』代表所有資料表)
        config.SetEntitySetAccessRule("*", EntitySetRights.All)
        config.UseVerboseErrors = True
    End Sub
End Class
==<end>==============



==<box>===========
程式2
 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
'設定調用URL→WebDataService2.svc
   Dim ServiceContext As New System.Data.Services.Client.DataServiceContext(New Uri("WebDataService2.svc", UriKind.Relative))
'送出抓取資料的命令
'→WebDataService2.svc/Customers?$filter=Country eq 'Germany'
'預期回傳值為Customers
  ServiceContext.BeginExecute(Of ServiceReference2.Customers)(New Uri("Customers?$filter=Country eq 'Germany'", UriKind.Relative), AddressOf loadDataCallback, ServiceContext)
 End Sub
==<end>==============




==<box>===========
程式3
'call back handler
Private Sub loadDataCallback(ByVal asyncResult As IAsyncResult)
 Dim ctx As System.Data.Services.Client.DataServiceContext = asyncResult.AsyncState
'抓回取得的資料(型別為Customers, 因預期回傳值為Customers)
 Dim result = ctx.EndExecute(Of ServiceReference2.Customers)(asyncResult)
'將取得的資料填入ListBox1
   For Each item As ServiceReference2.Customers In result
      ListBox1.Items.Add(item.CompanyName)
   Next
'顯示訊息
Windows.Browser.HtmlPage.Window.Alert("OK")
End Sub

==<end>==============



==<box>===========
程式4
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
'建立服務
 Dim srv1 As New ServiceReference1.cNorthWindEntities(New Uri("WebDataService1.svc", UriKind.Relative))
'建立Query
 Dim userQuery As System.Data.Services.Client.DataServiceQuery(Of ServiceReference1.客戶)
  userQuery = From c In srv1.客戶 Where c.城市 = "台中市"
'執行Query, 以QueryCallback接收回傳值
End Sub
==<end>==============



==<box>===========
程式5
'接收回傳值
Sub QueryCallback(ByVal result As System.IAsyncResult)
 Dim query As System.Data.Services.Client.DataServiceQuery(Of ServiceReference1.客戶) = result.AsyncState
'將抓取到的資料填入ListBox
 Dim ReturnData = query.EndExecute(result)
  For Each item As ServiceReference1.客戶 In ReturnData
   Me.ListBox1.Items.Add(item.公司名稱)
  Next
'顯示訊息
Windows.Browser.HtmlPage.Window.Alert("OK")
End Sub
==<end>==============




==<box>===========
程式6
Dim ServiceContext As ServiceReference1.cNorthWindEntities
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
'設定調用URL→遠端ADO.NET Data Service -->WebDataService1.svc
  ServiceContext = New ServiceReference1.cNorthWindEntities(New Uri("WebDataService1.svc", UriKind.Relative))
'建立『客戶』物件實體
   Dim NewCustomer As New ServiceReference1.客戶
'指定值
   NewCustomer.客戶編號 = Me.Txb_CustID.Text
   NewCustomer.公司名稱 = Me.Txb_CustName.Text
   NewCustomer.行政區 = "台北"
'新增至資料表
   ServiceContext.AddTo客戶(NewCustomer)
'調用非同步儲存動作(事件處理函式:OnSaveChangesCompleted)
   ServiceContext.BeginSaveChanges(AddressOf OnSaveChangesCompleted, NewCustomer)
End Sub

Private Sub OnSaveChangesCompleted(ByVal result As IAsyncResult)
  Try
'結束非同步新增動作
  ServiceContext.EndSaveChanges(result)
'顯示訊息
  Windows.Browser.HtmlPage.Window.Alert(" 成功: " & TryCast(result.AsyncState, ServiceReference1.客戶).客戶編號)
  Catch ex As System.Data.Services.Client.DataServiceRequestException
  Windows.Browser.HtmlPage.Window.Alert(" Error: " & ex.Response.BatchStatusCode)
End Try
End Sub
==<end>==============




==<box>===========
程式7
'ADO.NET Data Service proxy
Dim svcContext As ServiceReference1.cNorthWindEntities
'存放資料用
Dim DataCollection As ObservableCollection(Of ServiceReference1.客戶)
'取得資料(填入DataGrid)
 Sub GetData()
'設定調用URL --> WebDataService1.svc
  svcContext = New ServiceReference1.cNorthWindEntities(New Uri("WebDataService1.svc", UriKind.Relative))
'存放資料用
  DataCollection = New ObservableCollection(Of ServiceReference1.客戶)()
'抓取資料(客戶資料表)
Dim query As System.Data.Services.Client.DataServiceQuery(Of ServiceReference1.客戶) = svcContext.客戶
  Try
'非同步抓取資料
  query.BeginExecute(AddressOf GetDataCallback, query)
  Catch ex As System.Data.Services.Client.DataServiceRequestException
   Windows.Browser.HtmlPage.Window.Alert("OnGetData Error: " & ex.Response.ToString())
  End Try
End Sub
'取回非同步抓取資料的值(填入DataGrid)
Private Sub GetDataCallback(ByVal result As IAsyncResult)
 Try
Dim queryResult As System.Data.Services.Client.DataServiceQuery(Of ServiceReference1.客戶) = result.AsyncState
 Dim results = queryResult.EndExecute(result)

  For Each item As ServiceReference1.客戶 In results
'將取得的資料填入DataCollection
   DataCollection.Add(item)
   Next
'將DataCollection填入DataGrid
   DataGrid1.DataContext = DataCollection
 Catch ex As System.Data.Services.Client.DataServiceRequestException
  Windows.Browser.HtmlPage.Window.Alert("GetDataCallback Error: " & ex.Response.ToString())
 End Try
End Sub
==<end>==============
　　




==<box>===========
程式8
Private Sub Button_delete_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
 Dim DataRecord As ServiceReference1.客戶
'被選取的記錄
  DataRecord = DataGrid1.SelectedItem
'刪除資料
  DeleteRecord(DataRecord)
'顯示訊息
  Windows.Browser.HtmlPage.Window.Alert("OK")
 End Sub
'刪除記錄
 Sub DeleteRecord(ByVal dataRecord As ServiceReference1.客戶)
  Try
    svcContext.DeleteObject(dataRecord)
    svcContext.BeginSaveChanges(AddressOf OnSaveChangesCompleted, svcContext)
  Catch ex As System.Data.Services.Client.DataServiceRequestException
    Windows.Browser.HtmlPage.Window.Alert(" Error: " & ex.Response.ToString())
  End Try
 End Sub
==<end>==============
　　

　　
==<box>===========
程式9
'更新記錄
Sub UpdateRecord(ByVal dataRecord As ServiceReference1.客戶)
  Try
   svcContext.UpdateObject(dataRecord)
   svcContext.BeginSaveChanges(AddressOf OnSaveChangesCompleted, svcContext)
  Catch ex As System.Data.Services.Client.DataServiceRequestException
   Windows.Browser.HtmlPage.Window.Alert(" Error: " & ex.Response.ToString())
  End Try
End Sub
==<end>==============