10. 把Visual Studio .Net的当前窗口切换到Form1.vb的代码编辑窗口，并用下列代码替换Form1.vb中的Button1的Click事件对应的处理代码，下列代码功能是使用Web Service中提供的"Binding"服务对DataGrid组件实现数据绑定：
Private Sub Button1_Click (
ByVal sender As System.Object , ByVal e As System.EventArgs )
Handles Button1.Click
Dim MyService As New localhost.Service1 ( )
DataGrid1.DataSource = MyService.Binding ( )
DataGrid1.DataMember = "Cust"
End Sub |
11. 用下列代码替换Form1.vb中的Button2的Click事件对应的处理代码，下列代码功能是使用Web Service中提供的"Update"服务实现通过DataGrid来修改数据库数据：
Private Sub Button2_Click (
ByVal sender As System.Object , ByVal e As System.EventArgs )
Handles Button2.Click
Dim MyService As New localhost.Service1 ( )
Dim ds As DataSet = DataGrid1.DataSource
Dim dsChanges As DataSet = ds.GetChanges ( )
If Not ( dsChanges Is Nothing ) Then
ds.Merge ( MyService.Update ( dsChanges ) , True )
End If
End Sub |
12. 至此, 【TestWebService】项目的全部工作就完成了，调用Web Service是不是很简单。此时单击快捷键F5运行程序后。单击程序中的【绑定】按钮就会对程序中的DataGrid组件实现数据绑定，单击程序中的【修改】按钮，则程序会根据DataGrid中的内容来更新数据库，图05就是【TestWebService】的运行界面：
图05:【TestWebService】的运行界面
13. Form1.vb的代码清单如下：
Public Class Form1
Inherits System.Windows.Forms.Form
#Region " Windows 窗体设计器生成的代码 "
Public Sub New ( )
MyBase.New ( )
'该调用是 Windows 窗体设计器所必需的。
InitializeComponent ( )
'在 InitializeComponent ( ) 调用之后添加任何初始化
End Sub
'窗体重写处置以清理组件列表。
Protected Overloads Overrides Sub Dispose (
ByVal disposing As Boolean )
If disposing Then
If Not ( components Is Nothing ) Then
components.Dispose ( )
End If
End If
MyBase.Dispose ( disposing )
End Sub
'Windows 窗体设计器所必需的
Private components As System.ComponentModel.IContainer
'注意：以下过程是 Windows 窗体设计器所必需的
'可以使用 Windows 窗体设计器修改此过程。
'不要使用代码编辑器修改它。
Friend WithEvents Button1 As System.Windows.Forms.Button
Friend WithEvents Button2 As System.Windows.Forms.Button
Friend WithEvents DataGrid1 As System.Windows.Forms.DataGrid
Private Sub InitializeComponent ( )
Me.Button1 = New System.Windows.Forms.Button ( )
Me.Button2 = New System.Windows.Forms.Button ( )
Me.DataGrid1 = New System.Windows.Forms.DataGrid ( )
CType ( Me.DataGrid1 ,
System.ComponentModel.ISupportInitialize ) .BeginInit ( )
Me.SuspendLayout ( )
Me.Button1.FlatStyle = System.Windows.Forms.FlatStyle.Flat
Me.Button1.Location = New System.Drawing.Point ( 56 , 216 )
Me.Button1.Name = "Button1"
Me.Button1.Size = New System.Drawing.Size ( 75 , 32 )
Me.Button1.TabIndex = 0
Me.Button1.Text = "绑定"
Me.Button2.FlatStyle = System.Windows.Forms.FlatStyle.Flat
Me.Button2.Location = New System.Drawing.Point ( 168 , 216 )
Me.Button2.Name = "Button2"
Me.Button2.Size = New System.Drawing.Size ( 75 , 32 )
Me.Button2.TabIndex = 1
Me.Button2.Text = "修改"
Me.DataGrid1.DataMember = ""
Me.DataGrid1.Dock = System.Windows.Forms.DockStyle.Top
Me.DataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText
Me.DataGrid1.Name = "DataGrid1"
Me.DataGrid1.Size = New System.Drawing.Size ( 292 , 192 )
Me.DataGrid1.TabIndex = 2
Me.AutoScaleBaseSize = New System.Drawing.Size ( 6 , 14 )
Me.ClientSize = New System.Drawing.Size ( 292 , 273 )
Me.Controls.AddRange ( New System.Windows.Forms.Control ( )
{Me.DataGrid1 , Me.Button2 , Me.Button1} )
Me.Name = "Form1"
Me.Text = "测试Web Service"
CType ( Me.DataGrid1 ,
System.ComponentModel.ISupportInitialize ) .EndInit ( )
Me.ResumeLayout ( False )
End Sub
#End Region
Private Sub Button1_Click ( ByVal sender As System.Object ,
ByVal e As System.EventArgs ) Handles Button1.Click
Dim MyService As New localhost.Service1 ( )
DataGrid1.DataSource = MyService.Binding ( )
DataGrid1.DataMember = "Cust"
End Sub
Private Sub Button2_Click ( ByVal sender As System.Object ,
ByVal e As System.EventArgs ) Handles Button2.Click
Dim MyService As New localhost.Service1 ( )
Dim ds As DataSet = DataGrid1.DataSource
Dim dsChanges As DataSet = ds.GetChanges ( )
If Not ( dsChanges Is Nothing ) Then
ds.Merge ( MyService.Update ( dsChanges ) , True )
End If
End Sub
End Class |
六.总结
本文介绍了Web Service在目前大行其道的原因，并结合二个示例介绍Visual Basic .Net在Web Service的实现和调用上的强大功能，正如本文前面所说，Visual Studio .Net的出现使得web Service的这项原先繁杂的工作变得异常的简单，因为Visual Basic .Net已经替代我们作了这些描述性的、基础的底层工作，以至于你不需要了解为什么，只需要知道你要实现什么就可以编写、调用Web Service了。 在实现Web Service在数据库方面应用所显示
Web Service虽然以其强大功能和其优越性正在受到越来越多人的青睐，但也不可以回避它的缺点，譬如其速度慢就使得我几乎无法忍受。等等这样的原因也决定了Web Service并不适用于所有的环境。如单机运行程序和局域网上的同构应用程序等就尽量不采用Web Service方式。本文只是展示了Visual Studio .Net在Web Service上的初步用途。
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