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。
![](http://www.chinaz.com/upimg/userup/0810/2GI6022439.jpg)
图04【TestWebService】项目中组件排列位置和顺序
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:
以下为引用的内容:
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
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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:
以下为引用的内容:
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
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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:
![](http://www.chinaz.com/upimg/userup/0810/2GIP23444.jpg)
图05:【TestWebService】的运行界面
13. Form1.vb的代码清单如下:
以下为引用的内容:
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
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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。