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AUTHOR
Ken, Lin Kam Hung
Microsoft MVP,
Microsoft(Taiwan) Community Star
MCP, MCP+I, MCSA, MCSE(NT4 & Win2K), MCSE+I,
MCDBA(SQL7 & SQL2K), MCSD(VB6), MCAD(VB.NET),
Vice President of Hong Kong .NET User Group
SUMMARY
An XML Web Service is an internet standard and this article demonstrates how to
build and consume an XML Web Service in Visual Basic .NET.
REQUIREMENTS
The following list outlines the recommended hardware, software, network
infrastructure, and service pack that you need:
-- Visual Basic .NET
This article assumes that you are familiar with the following topic:
-- Visual Basic .NET
OBJECTIVES
After Completing this lab, you will be
able to :
1) Create an XML Web Service that providing a simple
calculation; Exercise 1
2) Create an Web Application that consumes the XML Web
Service; Exercise 2
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EXERCISE 1 CREATING AN XML WEB SERVICE
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In this exercise, you will create an XML Web Service
project that you will in later exercises. You will create few Web Service
Methods that doing simple calculation.
Create an XML Web Service Solution
1) Open Visual Studio .NET, Click New Project;
2) Select ASP.NET Web Service Template from Visual Basic
Project Project Type;
3) Type http://localhost/WSCalculation
in the location;
4) Rename Service1.asmx into SimpleCalculation.asmx
in the Solution Explorer.
Create XML Web Service Methods
1) Right click on SimpleCalculation.asmx and
click View Code;
2) Change the service1 into SimpleCalculation, your code should be look like,
Public Class
SimpleCalculation
Inherits System.Web.Services.WebService
3) Insert the Add Function with the following code,
<WebMethod()> _
Public Function Add(ByVal
x as Integer, ByVal y
as Integer) As Integer
Return
(x + y)
End Function
4) Insert the Subtract, Multiply and Divide functions;
5) Your code should look like as the following,
Imports System.Web.Services
<System.Web.Services.WebService(Namespace
:="http://tempuri.org/WSCalculation/SimpleCalculation")> _
Public Class SimpleCalculation
Inherits
System.Web.Services.WebService
<WebMethod()> _
Public Function Add(ByVal
x as Integer, ByVal y
as Integer) As Integer
Return
(x + y)
End Function
<WebMethod()> _
Public Function Subtract(ByVal
x as Integer, ByVal y
as Integer) As Integer
Return
(x - y)
End Function
<WebMethod()> _
Public Function Multiply(ByVal
x as Integer, ByVal y
as Integer) As Integer
Return
(x - y)
End Function
<WebMethod()> _
Public Function Divide(ByVal
x as Integer, ByVal y
as Integer) As Integer
Return
(x / y)
End Function
End Class
Debug and Build the XML Web Service
1) Click Start from the Debug
Menu;
2) An Internet Explorer should be open if there is no error in
your project;
3) You may test the web methods' functionalities by clicking any link;
4) Close Your Internet Explorer and leave your Visual
Studio .NET and the solution open
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EXERCISE 2 USING THE XML WEB SERVICE
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In this Exercise, You will create an Web Application project that use the Web
Service which built in last exercise
Create the Web Application
1) In Solution Explorer, right click your
solution and click Add-->New Project(if you have close
Visual Studio .NET, you may open it again and select on WSCalculation);
2) Select ASP.NET Web Application Template from Visual
Basic Project Project Type;
3) Type http://localhost/SimpleMath
in the Location;
4) Open WebForm1.aspx from the Solution Explorer;
5) Drop two TextBox, one Label, one Button,
one DropDownList and two RequiredFieldValidator
to the Design Panel;
6) Right click on WebForm1.aspx and click View Code
to open the WebForm1.aspx.vb
7) Add the following code in Page_Load Section to set
the inital Setting,
If Not Page.IsPostBack
Then
Button1.Text = " = "
Me.DropDownList1.Items.Add(New
ListItem("+", "Add"))
Me.DropDownList1.Items.Add(New
ListItem("-", "Subtract"))
Me.DropDownList1.Items.Add(New
ListItem("*", "Multiply"))
Me.DropDownList1.Items.Add(New
ListItem("/", "Divide"))
Label1.Text = ""
Me.RequiredFieldValidator1.ControlToValidate
= "Textbox1"
Me.RequiredFieldValidator1.Display
= ValidatorDisplay.Dynamic
Me.RequiredFieldValidator1.ErrorMessage
= "Please enter value"
Me.RequiredFieldValidator2.ControlToValidate
= "textbox2"
Me.RequiredFieldValidator2.Display
= ValidatorDisplay.Dynamic
Me.RequiredFieldValidator2.ErrorMessage
= "Please enter value"
End If
8) In Solution Expplorer, right click Reference
under the current project and select Add Web Reference;
9) Type http://localhost/WSCalcuation/SimpleCalculation.asmx
in the URL and click Add Reference;
10) You will see a new Web Reference has added and rename the
Localhost into WSCalculation;
11) Open the WebForm1.aspx and double click on Button1,
a new function called Button1_Click has been added to WebForm1.aspx.vb;
12) Add the following code under Button1_Click,
Dim WS1 As New
WSCalculation.SimpleCalculation
Dim x, y, z As
Integer
x = CType(TextBox1.Text,
Integer)
y = CType(TextBox2.Text,
Integer)
Select Case Me.DropDownList1.SelectedValue
Case "Add"
z =
WS1.Add(x, y)
Case "Subtract"
z =
WS1.Subtract(x, y)
Case "Multiply"
z =
WS1.Multiply(x, y)
Case "Divide"
z =
WS1.Divide(x, y)
End Select
Label1.Text = z
13) Now your code should be look like as the following,
Public Class WebForm1
Inherits
System.Web.UI.Page
Private Sub Page_Load(ByVal
sender As System.Object, ByVal
e As System.EventArgs) Handles MyBase .Load
If Not Page.IsPostBack
Then
Button1.Text = " = "
Me.DropDownList1.Items.Add(New
ListItem("+", "Add"))
Me.DropDownList1.Items.Add(New ListItem("-",
"Subtract"))
Me.DropDownList1.Items.Add(New ListItem("*",
"Multiply"))
Me.DropDownList1.Items.Add(New ListItem("/",
"Divide"))
Label1.Text
= ""
Me.RequiredFieldValidator1.ControlToValidate = "Textbox1"
Me.RequiredFieldValidator1.Display = ValidatorDisplay.Dynamic
Me.RequiredFieldValidator1.ErrorMessage = "Please enter value"
Me.RequiredFieldValidator2.ControlToValidate = "textbox2"
Me.RequiredFieldValidator2.Display = ValidatorDisplay.Dynamic
Me.RequiredFieldValidator2.ErrorMessage = "Please enter value"
End If
End Sub
Private Sub Button1_Click(ByVal sender As
System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Dim WS1
As New WSCalculation.SimpleCalculation
Dim x,
y, z As Integer
x = CType(TextBox1.Text,
Integer)
y = CType(TextBox2.Text,
Integer)
Select Case Me.DropDownList1.SelectedValue
Case "Add"
z = WS1.Add(x, y)
Case "Subtract"
z = WS1.Subtract(x, y)
Case "Multiply"
z = WS1.Multiply(x, y)
Case "Divide"
z = WS1.Divide(x, y)
End Select
Label1.Text = z
End Sub
End Class
Debug and Build the Web Application that
Consuming XML Web Service
1) In Solution Explorer, right click on
SimpleMath Project and select Set As Startup Project;
2) Right click on WebForm1.aspx and Select Set As Start
Page;
3) Click Start from the Debug Menu;
4) An Internet Explorer should be open if there is no error in
your project;
5) You may test the application by entering some value to the TextBoxes
and click the Button;
6) Close your Internet Explorer, Close Visual
Studio .NET.
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