Home > Articles


📄 Contents

  1. Chapter 3: Consuming a Simple Web Service with .NET SDK
  2. Creating the Web Service Consumer
  3. Testing the Web Service Consumer
  4. Summary

Chapter 3: Consuming a Simple Web Service with .NET SDK

In Chapter 2, "Creating a Simple Web Service with .NET SDK," using little more than a text editor and the .NET SDK's utilities, you created and tested a Web Service. In this chapter, you'll use the same tools to consume the Web Service in a Web Forms application, which is the enhanced version of the Active Server Pages applications you might have created in the past (see Figure 3.1). Your Web Forms application will call your Web Service, gather information, and then synthesize it into a Web page that's delivered to your Web Browser.

Figure 3.1 The basic architecture of your application.

Although you are creating a Web Service and a Web Forms application on the same computer for the purpose of this example, that's probably not how you will create production-quality applications. You will either create Web Services that others can use and access from anywhere, or you will create Web Forms applications (or Windows Forms applications) that use Web Services other organizations have created. To simulate two different Web Servers for this example, you will actually create a new sub-Web in your Default Web Site node in Internet Information Services.

How to Consume a Web Service

To consume a Web Service within your application, you have to know the following:

  • The location (URI) of the Web Service's WSDL file. You can find this information in a number of different ways. Someone could supply it to you, you could use DISCO to find it on a particular server, or you could use a UDDI search engine for Web Services. DISCO and UDDI are covered in more detail in Chapters 9, "Understanding DISCO," and 25, "Understanding UDDI."

  • After you have the WSDL file, you can create a proxy to the Web Service, which acts as the mediator for all requests and responses to or from the Web Service (see Figure 3.2). The proxy allows you to develop your application as though the Web Service resided locally on your computer. It serializes your method requests into SOAP and then sends the SOAP message to the Web Service via the network. After the Web Service has finished processing your request and returns its results encoded in a SOAP message, the proxy steps into action by intercepting the message, deserializing it, and returning the results to your application. The proxy is important because it hides the gory details of SOAP serialization and network communications.

You will use the wsdl.exe utility that I mentioned in Chapter 2 to create a proxy for your Web Service so that you can use it in your Web Forms application.

Creating a Separate Web Folder in IIS

As I mentioned, you need to create a separate sub-Web in IIS to simulate your Web Service and Web Forms application running on two physically different machines. For this example, you'll create a folder on your hard drive called C:\pmcalc_web and create a sub-Web called pmcalc_web that points to the folder. (For instructions on how to create a sub-Web in IIS, refer to Chapter 2.)


This chapter assumes you are using just the .NET Framework that can be downloaded from Microsoft's MSDN site (msdn.microsoft.com). I recommend that you add a PATH statement to your autoexec.bat file in order to use the command line utilities from any directory. This will save you a lot of time rummaging through the folders on your hard drive to find the wsdl.exe, vb.exe, and csc.exe applications, and will save you a great deal of effort to include the proper /out: parameters when defining where you want the code generated or compiled. To add the PATH statement, first locate the correct Program Files directory (contains the wsdl.exe) and the Windows directory (contains vb.exe and csc.exe) for the .NET Framework. You should find the following locations:

    c:\Program Files\Microsoft.NET\FrameworkSDK\Bin

Therefore, you should add the following PATH statement in your autoexec.bat file:

    SET PATH=c:\Program Files\Microsoft.NET\FrameworkSDK\Bin;c:\Windows\

After you make this change, you must reboot. Now you will be able to use the necessary command line applications from ANY directory on your hard drive.

Using the wsdl.exe to Create Your Proxy

First, open a DOS command-prompt window. Remember to navigate to the folder C:\pmcalc_web in the DOS prompt before running wsdl.exe so that it creates the proxy code in the appropriate folder of your hard drive. If you don't, you might have to search your hard drive to find it! Alternatively, you can use the utility's /out: switch to specify the exact folder where you want the proxy code file created.

To generate a Visual Basic proxy, enter this line:

wsdl /language:vb http://localhost/pmcalc/pmcalc.asmx?wsdl

Figure 3.2 How the proxy works.

After a few moments, you should see the following confirmation:

Microsoft (R) Web Services Description Language Utility
[Microsoft .NET Framework Version 1.0.2728.2]
Copyright (C) Microsoft Corp 2000. All rights reserved.
Writing file `C:\pmcalc\pmcalc.vb'.

To generate a C# proxy, enter this line:

C:\pmcalc>wsdl /language:cs http://localhost/pmcalc/pmcalc.asmx?wsdl

After a few moments, you should see the following confirmation:

Microsoft (R) Web Services Description Language Utility
[Microsoft .NET Framework Version 1.0.2728.2]
Copyright (C) Microsoft Corp 2000. All rights reserved.
Writing file `C:\pmcalc\pmcalc.cs'.

Examining the Generated Proxy Class

The wsdl.exe utility has created the source code for your proxy class. You will compile it into a component in a moment, but first inspect the source code to learn a little bit about how the proxy works. Use your favorite text editor and open the pmcalc.vb (for Visual Basic; see Listing 3.1) or pmcalc.cs (for C#; see Listing 3.2) file.

Listing 3.1  The pmcalc.vb Proxy File

` <autogenerated>
`     This code was generated by a tool.
`     Runtime Version: 1.0.2728.2
`     Changes to this file may cause incorrect behavior and will be lost if 
`     the code is regenerated.
` </autogenerated>

Option Strict On
Option Explicit On

Imports System
Imports System.Web.Services
Imports System.Web.Services.Protocols
Imports System.Xml.Serialization

`This source code was auto-generated by wsdl, Version=1.0.2728.2.

[Namespace]:="http://tempuri.org/")>  _
Public Class pmcalc
    Inherits System.Web.Services.Protocols.SoapHttpClientProtocol
    Public Sub New()
        Me.Url = "http://localhost/pmcalc/pmcalc.asmx"
    End Sub
ParameterStyle:=System.Web.Services.Protocols.SoapParameterStyle.Wrapped)>  _
    Public Function developerEstimate(ByVal xintHours As Integer) As Double
        Dim results() As Object = Me.Invoke("developerEstimate", New Object() 
        Return CType(results(0),Double)
    End Function
    Public Function BegindeveloperEstimate(ByVal xintHours As Integer, ByVal 
	callback As System.AsyncCallback, ByVal asyncState As Object) 
	As System.IAsyncResult
        Return Me.BeginInvoke("developerEstimate", New Object() {xintHours}, 
		callback, asyncState)
    End Function
    Public Function EnddeveloperEstimate(ByVal asyncResult As 
	System.IAsyncResult) As Double
        Dim results() As Object = Me.EndInvoke(asyncResult)
        Return CType(results(0),Double)
    End Function
End Class

Listing 3.2  The pmcalc.cs Proxy File

// <autogenerated>
//     This code was generated by a tool.
//     Runtime Version: 1.0.2728.2
//     Changes to this file may cause incorrect behavior and will be lost if 
//     the code is regenerated.
// </autogenerated>

// This source code was auto-generated by wsdl, Version=1.0.2728.2.
using System.Xml.Serialization;
using System;
using System.Web.Services.Protocols;
using System.Web.Services;

public class pmcalc : System.Web.Services.Protocols.SoapHttpClientProtocol {
    public pmcalc() {
        this.Url = "http://localhost/pmcalc/pmcalc.asmx";
developerEstimate", Use=System.Web.Services.Description.SoapBindingUse.Literal, 
    public System.Double developerEstimate(int xintHours) {
        object[] results = this.Invoke("developerEstimate", new object[] 
        return ((System.Double)(results[0]));
    public System.IAsyncResult BegindeveloperEstimate(int xintHours, 
	System.AsyncCallback callback, object asyncState) {
        return this.BeginInvoke("developerEstimate", new object[] {xintHours}, 
		callback, asyncState);
    public System.Double EnddeveloperEstimate(System.IAsyncResult asyncResult) {
        object[] results = this.EndInvoke(asyncResult);
        return ((System.Double)(results[0]));

Regardless of whether you use C# or Visual Basic.NET, you can see how the wsdl.exe utility performed a great service for you. The class itself inherits from System.Web.Services.Protocols.SoapClientProtocol, and then uses the Me (this) statement to refer to its instance. It then sets properties such as the URL when it is instantiated in the New method. This pmcalc class has three methods. The first is DeveloperEstimate, which you use in your Web Forms application. The next two methods, BeginDeveloperEstimate and EndDeveloperEstimate, allow for asynchronous calls to Web Services (covered in more depth in Chapter 19, "Calling Web Services Asynchronously"). When your Web Forms application calls the DeveloperEstimate method, your class calls the Invoke method on itself. This call starts the serialization and transportation of your information over the network and also handles deserialization in the response to your call. All this functionality is encapsulated in the System.Web.Services.Protocols.SoapClientProtocol class.

Compiling the Proxy

Now that you have the source code for your proxy, you need to compile it into a .NET Assembly. To accomplish this, the .NET Framework supplies you with a Visual Basic compiler (vbc.exe) and a C# compiler (csc.exe).

Before you compile, you'll need to create a folder called \bin as a subfolder in your pmcalc_web folder, as shown here:


To compile the proxy code, you'll need to navigate to the DOS prompt and type the following command for the Visual Basic.NET compiler:

vbc.exe /out:bin\pmcalc.dll /target:library 
/reference:system.xml.serialization.dll /reference:system.web.services.dll 

If everything worked correctly, you will see the following message:

Microsoft (R) Visual Basic.NET Compiler version 7.00.9030
for Microsoft (R) .NET Framework Common Language Runtime version 1.00.2204.21
Copyright (C) Microsoft Corp 2000. All rights reserved.

For the C# compiler, enter this command:

csc.exe /out:bin\pmcalc.dll /target:library 
/reference:system.xml.serialization.dll /reference:system.web.services.dll 

If you have typed in the command correctly, you should see the following confirmation message:

Microsoft (R) Visual C# Compiler Version 7.00.9030 [CLR version 1.00.2204.21]
Copyright (C) Microsoft Corp 2000. All rights reserved.

Chapter 6, "How ASP.NET Works," explains in more detail what the compiler does. Briefly, the compiler does not compile your source code into native machine-level code. Instead, it creates an assembly (.dll file) containing Intermediate Language that's later compiled into machine language code by a "Just In Time" compiler specific to your operating system and computer chip.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020