Calling a Web Service using VB6 with SOAP 3.0 - The web services used in the tutorial
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The following are the web services for which client applications call the services using VB 6.0 code. Herein two of the services considered in earlier tutorials will be used.
The first service to be called is a web service created using ColdFusion. The details of this service are described in a tutorial that will appear in the future in DevArticles.com with the title Creating a Web Service with ColdFusion: the Basics. In brief, a registered CFC (ColdFusion Component) which is based on a ColdFusion function shown below is implemented as the web service:
<cfcomponent>
<cffunction name="WelcomeMsg" access="remote" returntype="string"
output="no">
<cfargument name="name" type="string" required="yes">
<cfreturn "<h3><font color='blue'>Welcome to my Web Service Site
</font></h3> "
& arguments.name &"! " & "What would you like to do?">
</cffunction>
</cfcomponent>
In the above service the web service method name is WelcomeMsg(). It just takes one argument, which is a string. The service will return a html fragment after processing and adding some tags.
The client coding with VB6, example 1: Calling a ColdFusion web serviceThe first thing to do is create a standard EXE project. In this case a generic client is declared, and this is set using the CreateObject() function with the object Id being the MSSoapClient.
Add a text box and a command button to your form. To the click event of the command button add the following code. This is the case of late binding, as no type library is referenced. You may check that in the object browser.
Private Sub Command1_Click()
Dim client
Set client = CreateObject("MSSOAP.SoapClient30")
oClient.MSSoapInit _ "http://localhost/CF_WebSvc/justFunction.cfc?wsdl"
strg = (oClient.WelcomeMsg(Text1.Text))
MsgBox (strg)
If Err.Number = -2147024809 Then
MsgBox "Invalid Web Service Request. Please check the Web Service URL"
End If
End Sub
It is assumed that you have the service hosted on the localhost at the designated directory. Make sure that your web reference is showing a valid WSDL. The question is, how does one know that the client has a method called WelcomeMsg()? This is where the WSDL can be used to advantage as it will show both the request sent and the responses expected, as well as the methods called. Please review earlier tutorials.
When you run the above code you should get the following response from the web service.
Next: Example 2: Calling a ColdFusion web service >>
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