| 在这个例子中，我们将定义一个mathservice类，来对两个数字分别进行加，减，乘，除。当然这个类需要从基类web service中继承。请先看该程序的源代码：
源文件：webservice\math.asmx <%@ WebService Language="VB" Class="MathService" %>
Imports System
Imports System.Web.Services
Public Class MathService : Inherits WebService
Public Function <WebMethod()> Add(A As Integer, B As Integer) As Integer
Return A + B
End Function
Public Function <WebMethod()> Subtract(A As Integer, B As Integer) As Integer Return A - B
End Function
Public Function <WebMethod()> Multiply(A As Integer, B As Integer) As Integer
Return A * B
End Function
Public Function <WebMethod()> Divide(A As Integer, B As Integer) As Integer
If B = 0
Return -1
End If
Return CInt(A / B)
End Function
我们还是举“加”，“减”，“乘”，“除”的例子。
我们先创建一个文件用于客户端的用户浏览：
<%@ Import Namespace="MathServiceSpace" %>
<html>
<script language="VB" runat="server">
Dim Op1 As Integer = 0
Dim Op2 As Integer = 0
Public Sub Submit_Click(Sender As Object, E As EventArgs)
Try
Op1 = Int32.Parse(Operand1.Text)
Op2 = Int32.Parse(Operand2.Text)
Catch Exp As Exception
' Ignored
End Try Dim Service As MathService = New MathService()
Select (CType(sender,Control).ID)
Case "Add" :
Result.Text = "<b>Result</b> = " & Service.Add(Op1, Op2).ToString()
Case "Subtract" :
Result.Text = "<b>Result</b> = " & Service.Subtract(Op1, Op2).ToString()
Case "Multiply" :
Result.Text = "<b>Result</b> = " & Service.Multiply(Op1, Op2).ToString()
Case "Divide" :
Result.Text = "<b>Result</b> = " & Service.Divide(Op1, Op2).ToString()
End Select
End Sub
</script>
<body style="font: 10pt verdana">
<h4>Using a Simple Math Service </h4>
<form runat="server">
<div style="padding:15,15,15,15;background-color:beige;width:300;border-color:black;border-width:1;border-style:solid">
Operand 1: <br><asp:TextBox id="Operand1" Text="15" runat="server"/><br>
Operand 2: <br><asp:TextBox id="Operand2" Text="5" runat="server"/><p>
<input type="submit" id="Add" value="Add" OnServerClick="Submit_Click" runat="server">
<input type="submit" id="Subtract" value="Subtract" OnServerClick="Submit_Click" runat="server">
<input type="submit" id="Multiply" value="Multiply" OnServerClick="Submit_Click" runat="server">
<input type="submit" id="Divide" value="Divide" OnServerClick="Submit_Click" runat="server">
<p>
<asp:Label id="Result" runat="server"/>
</div>
</form>
</body>
</html>
我们还需要一个sdl文件，当然这个文件不用手工输入，我们在浏览一个.asmx的时候，在后缀名后直接加上？sdl可以自动生成sdl文件。
然后我们在一个.vb文件里，将定义一个名字空间，.vb文件的内容：
Imports System.Xml.Serialization
Imports System.Web.Services.Protocols
Imports System.Web.Services Namespace MathServiceSpace
Public Class MathService
Inherits System.Web.Services.Protocols.SoapClientProtocol
Public Sub New()
MyBase.New
Me.Url = "http://localhost/QuickStart/aspplus/samples/services/MathService/VB/MathService.a"& _
"smx"
End Sub
Public Function <System.Web.Services.Protocols.SoapMethodAttribute("http://tempuri.org/Add")> Add(ByVal <System.Xml.Serialization.XmlElementAttribute("A", IsNullable:=false)> a As Integer, ByVal <System.Xml.Serialization.XmlElementAttribute("B", IsNullable:=false)> b As Integer) As Integer
Dim results() As Object = Me.Invoke("Add", New Object() {a, b})
Return CType(results(0),Integer)
End Function
Public Function BeginAdd(ByVal a As Integer, ByVal b As Integer, ByVal callback As System.AsyncCallback, ByVal asyncState As Object) As System.IAsyncResult
Return Me.BeginInvoke("Add", New Object() {a, b}, callback, asyncState)
End Function
Public Function EndAdd(ByVal asyncResult As System.IAsyncResult) As Integer
Dim results() As Object = Me.EndInvoke(asyncResult)
Return CType(results(0),Integer)
End Function
Public Function <System.Web.Services.Protocols.SoapMethodAttribute("http://tempuri.org/Subtract")> Subtract(ByVal <System.Xml.Serialization.XmlElementAttribute("A", IsNullable:=false)> a As Integer, ByVal <System.Xml.Serialization.XmlElementAttribute("B", IsNullable:=false)> b As Integer) As Integer
Dim results() As Object = Me.Invoke("Subtract", New Object() {a, b})
Return CType(results(0),Integer)
End Function
Public Function BeginSubtract(ByVal a As Integer, ByVal b As Integer, ByVal callback As System.AsyncCallback, ByVal asyncState As Object) As System.IAsyncResult
Return Me.BeginInvoke("Subtract", New Object() {a, b}, callback, asyncState)
End Function
Public Function EndSubtract(ByVal asyncResult As System.IAsyncResult) As Integer
Dim results() As Object = Me.EndInvoke(asyncResult)
Return CType(results(0),Integer)
End Function
Public Function <System.Web.Services.Protocols.SoapMethodAttribute("http://tempuri.org/Multiply")> Multiply(ByVal <System.Xml.Serialization.XmlElementAttribute("A", IsNullable:=false)> a As Integer, ByVal <System.Xml.Serialization.XmlElementAttribute("B", IsNullable:=false)> b As Integer) As Integer
Dim results() As Object = Me.Invoke("Multiply", New Object() {a, b})
Return CType(results(0),Integer)
End Function
Public Function BeginMultiply(ByVal a As Integer, ByVal b As Integer, ByVal callback As System.AsyncCallback, ByVal asyncState As Object) As System.IAsyncResult
Return Me.BeginInvoke("Multiply", New Object() {a, b}, callback, asyncState)
End Function
Public Function EndMultiply(ByVal asyncResult As System.IAsyncResult) As Integer
Dim results() As Object = Me.EndInvoke(asyncResult)
Return CType(results(0),Integer)
End Function
Public Function <System.Web.Services.Protocols.SoapMethodAttribute("http://tempuri.org/Divide")> Divide(ByVal <System.Xml.Serialization.XmlElementAttribute("A", IsNullable:=false)> a As Integer, ByVal <System.Xml.Serialization.XmlElementAttribute("B", IsNullable:=false)> b As Integer) As Integer
Dim results() As Object = Me.Invoke("Divide", New Object() {a, b})
Return CType(results(0),Integer)
End Function
Public Function BeginDivide(ByVal a As Integer, ByVal b As Integer, ByVal callback As System.AsyncCallback, ByVal asyncState As Object) As System.IAsyncResult
Return Me.BeginInvoke("Divide", New Object() {a, b}, callback, asyncState)
End Function
Public Function EndDivide(ByVal asyncResult As System.IAsyncResult) As Integer
Dim results() As Object = Me.EndInvoke(asyncResult)
Return CType(results(0),Integer)
End Function
End Class
End Namespace
有了这四个文件，我们可以编辑一个批处理文件，执行如下的语句：
webserviceutil -c:proxy /pa:MathService.sdl /l:VB /n:MathServiceSpace
这样，我们就可以在客户端执行了。 5.2.1 小结
在这一章中，我们以提供计算加、减、乘、除的网络应用为例，详细的介绍了如何建立起一个完整的web service服务的步骤和注意事项，虽然这个例子和实际使用的应用环境有较大的差异，但基本方法应该是一致的。
第三章 数据交换
我们的这个例子说明了DataSet-----一个基于XML技术的强大的数据分离技术，能够用Web Service方法返回。DataSet能够在一个智能化的结构中存储复杂的信息和关系，这是Web Service的一个非常有用的方法。
通过DataSets的显示，你能够限制通过连接你的数据库服务器的测试。
GetTitleAuthors方法连接一个数据库并且运行两个SQL语句，第一个返回颜色的列表，另外一个返回字体大小的列表。方法把两个结果用一个DataSet来存储，并返回一个DataSet。
PutTitleAuthors说明一个Web Service方法把DataSet当作一个参数并返回一个整数，这个整数就是在DataSet中的“Table“表的行数。虽然这个方法执行起来有点简单，但是这个方法也能够与数据库服务器把过剩的数据聪明的合并在一起。
我们来看看这个例子，首先：
<%@ WebService Language="VB" Class="DataService" %>
这句话应该包括。我们还要引入这个名字空间：
Imports System.Web.Services
第一我们两个方法，Getcolor()：
Public Function <WebMethod()> Getcolor() As DataSet
Dim MyConnection As SQLConnection = New
SQLConnection("server=localhost;uid=sa;pwd=;database=howff")
Dim MyCommand1 As SQLDataSetCommand = New
SQLDataSetCommand("select * from color", MyConnection)
Dim MyCommand2 As SQLDataSetCommand = New
SQLDataSetCommand("select * from size", MyConnection)
'数据的填充
Dim DS As New DataSet
MyCommand1.FillDataSet(DS, "color")
MyCommand2.FillDataSet(DS, "size")
Return DS
End Function
Putcolor()方法：
Public Function <WebMethod()> Putcolor(DS As DataSet) As Integer
'返回行数
Return DS.Tables(0).Rows.Count
End Function 文件保存为webservice.asmx，放在虚拟目录下，具体代码如下：
源文件：webservice\webservice.asmx <%@ WebService Language="VB" Class="DataService" %> Imports System
Imports System.Data
Imports System.Data.SQL '引入System.Web.Services名字空间
Imports System.Web.Services Public Class DataService Public Function <WebMethod()> Getcolor() As DataSet
'创建数据库连接和命令集
Dim MyConnection As SQLConnection = New
SQLConnection("server=localhost;uid=sa;pwd=;database=howff")
Dim MyCommand1 As SQLDataSetCommand = New
SQLDataSetCommand("select * from color", MyConnection)
Dim MyCommand2 As SQLDataSetCommand = New
SQLDataSetCommand("select * from size", MyConnection)
'数据的填充
Dim DS As New DataSet
MyCommand1.FillDataSet(DS, "color")
MyCommand2.FillDataSet(DS, "size")
Return DS
End Function
'
Public Function <WebMethod()> Putcolor(DS As DataSet) As Integer
'返回行数
Return DS.Tables(0).Rows.Count
End Function End Class
一个简单的Web Service案例 |
