Consuming Webservice using MSSoap

Even though majority of the programmers have started using vb.net, there may be cases where you have a legacy system that still needs to consume webservice. This is how to do it with MSSoap.

First thing to be aware of is you may encounter issue if the webservice returns XML, so have it return a string instead. This is easily done by using a wrapper function. For example, if you have a webmethod say getLotData, just create a getLotDataStr as follows:

<WebMethod()> _
        Public Function getLotData(ByVal pLotID As String) As XmlDocument
           ....
        End Function

...

<WebMethod()>
        Public Function getLotDataStr(ByVal pLotID As String) As String
            Dim tmpStr As String = ""
            Dim xDoc As XmlDocument

            xDoc = getLotData(pLotID)
            tmpStr = xDoc.OuterXml

            Return tmpStr
        End Function

To consume the webservice, in vbscript or VB, you then use the MSSoap client as follows:

 Dim wsClient As New MSSOAPLib30.SoapClient30
 Dim urlStr as String = "http://www.blogger.com/wservice.asmx?WSDL"
 Dim sReply, lotID As String
 Dim xDoc As DOMDocument30

 lotID = ...
 wsClient.MSSoapInit urlStr
 sReply = wsClient.getLotDataStr(lotID)

 xDoc.loadXML sReply

 ...

Once the information is loaded to the XmlDocument, you can then access the information by using the getElementsByTagName. You can also access the inner text by access the Text Property.

E.g.

  Dim lotNode As IXMLDOMNode
 Dim processStep As String

 Set lotNode = xDoc.getElementByTagName("processID")
 ProcessStep = lotNode.Text


 'If it is an attribute then access it by the Attributes as in
 ProcessStep = lotNode.Attributes.getNameItem("Name").Text  

You can also use the DomDocument30 data type to create the parameters if the Webservice requires a XML as a parameter.