Call WebService using HTTPWebRequest object

[hharry]

Hi All,
I have a simple web service:
<WebMethod()> _
Public Function ReSample(ByVal sInput As Integer) As String
Return sInput * 5
End Function
I am trying to call this service from a second service by sending a
soap message using the HTTPWebRequest object.
Public Function CallReSample(By Val y As Integer) As String
Dim SoapEnv As String = ""
Dim url As String =
"http://localhost/AcxiomRequest/Service1.asmx/ReSample"
Dim result As String = ""
Dim myWriter As StreamWriter
SoapEnv = "" & _
"<soap:Envelope " & _
" xmlns:xsi=" + Chr(34) +
"http://www.w3.org/2001/XMLSchema-instance" + Chr(34) & _
" xmlns:xsd=" + Chr(34) +
"http://www.w3.org/2001/XMLSchema" + Chr(34) & _
" xmlns:soap=" + Chr(34) +
"http://schemas.xmlsoap .org/soap/envelope/" + Chr(34) + ">" & _
" <soap:Body>" & _
" <ReSample xmlns:m=" + Chr(34) +
"http://tempuri.org/message/" + Chr(34) + ">" & _
"<sInput>50 </sInput>" & _
" </ReSample>" & _
" </soap:Body>" & _
" </soap:Envelope>"
Dim objRequest As HttpWebRequest = WebRequest.Crea te(url)
If Not objRequest Is Nothing Then
objRequest.Meth od = "POST"
objRequest.Cont entLength = SoapEnv.Length
objRequest.Cont entType =
"applicatio n/x-www-form-urlencoded"
objRequest.Head ers.Add("SOAPAc tion", "ReSample")
myWriter = New StreamWriter(ob jRequest.GetReq uestStream())
myWriter.Write( SoapEnv)
If Not myWriter Is Nothing Then
myWriter.Close( )
End If
Dim objResponse As HttpWebResponse
Dim esr As StreamReader
Try
objResponse = objRequest.GetR esponse()
Catch ex As WebException 'Exception
esr = New StreamReader(ex .Response.GetRe sponseStream())

result = esr.ReadToEnd()
Catch ex As Exception
End Try
Dim sr As StreamReader
sr = New StreamReader(ob jResponse.GetRe sponseStream())
result = sr.ReadToEnd()
sr.Close()
objResponse.Clo se()
sr.Close()
objResponse = Nothing
sr = Nothing
objRequest.Abor t()
End If
objRequest = Nothing
myWriter = Nothing
End Function
////////////////////////////////////////////////////////////////////////

I keep getting the following error:
System.InvalidO perationExcepti on: Missing parameter: sInput.
I'm not sure how to include a parameter in the soap envelope.
Pointers appreciated
Thanks in advance!

[prabhupr]

Your return datatype is STRING in "Public Function ReSample(ByVal
sInput As Integer) As String "
May be you need to explicitly conver the type within the code "Return
sInput * 5 "

[hharry]

Thanks.

I changed my web method to:

<WebMethod()> _
Public Function ReSample(ByVal sInput As String) As String

Return sInput

End Function

So, I would expect the service to return the string "50", but still
getting the missing parameter exception.
I'm sure there is something missing from my soap envelope string.

[Jarod]

> So, I would expect the service to return the string "50", but still

getting the missing parameter exception.
I'm sure there is something missing from my soap envelope string.

Go to your webservice address through browser or in debug mode you have some
test site that presents you SOAP request that you should use, just copy it.
For example http://localhost/yourwebservice/thisservice.asmx and put it in
the browser.
Jarod

[hharry]

Thanks Jarod.

This pointed me in the right direction. My namespace was incorrect and
the content-type should have been "text/xml; charset=utf-8" as opposed
to "applicatio n/x-www-form-urlencoded".