CODEWITHSUNDEEP
.netvb.netweb-servicesoverloadingoption-type
user2366211
user2366211

Reputation: 13

web method in vb.net: optional parameters - too many for overloading

Old subject but with a twist - I searched and couldn't find answer to that.

I know I can't use optional parameters with default values with web method so I have to use function overloading but...I saw examples of one optional parameter and I have around 10!

If I understand well for 3 optional parameters I will need 7 overloaded functions (3 for 1 parameter, 3 for 2 and 1 for the whole 3) so for how many I need for 10? a lot! there must be a better way, no? and please don't tell me to use WCF - I can't switch to that now and I have to use WSDL

thanks a lot for helping

Upvotes: 1

Views: 7698

Answers (2)

George
George

Reputation: 2213

You can declare variables as Nullable (of <your type>) and just have one webservice with all 10 parameters

This is your Webmethod with only 2 optional parameters, but you can easily expand on this to 10:

    <WebMethod(Description:="TEST1")> _
Public Function TEST1(<XmlElement()> param1 As Nullable(Of Double), <XmlElement()> param2 As Nullable(Of Double)) As <XmlElement()> Double
    Try
        Dim result As Double = 0

        If Not param1 Is Nothing Then
            result += param1
        End If

        If Not param2 Is Nothing Then
            result += param2
        End If
        Return result
    Catch ex As Exception

    End Try
    Return 0
End Function

This SoapUI call:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:not="http://mysite.org/">
   <soapenv:Header/>
   <soapenv:Body>
      <not:TEST1>
         <not:param1>1</not:param1>
         <not:param2>2</not:param2>
      </not:TEST1>
   </soapenv:Body>
</soapenv:Envelope>

Results in this:

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
   <soap:Body>
      <TEST1Response xmlns="http://mysite.org/">
         <TEST1Result>3</TEST1Result>
      </TEST1Response>
   </soap:Body>
</soap:Envelope>

This SoapUI call:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:not="http://mysite.org/">
   <soapenv:Header/>
   <soapenv:Body>
      <not:TEST1>
         <not:param1>1</not:param1>
      </not:TEST1>
   </soapenv:Body>
</soapenv:Envelope>

Results in this:

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
   <soap:Body>
      <TEST1Response xmlns="http://mysite.org/">
         <TEST1Result>1</TEST1Result>
      </TEST1Response>
   </soap:Body>
</soap:Envelope>

Nullable (of Double) in this example both parameters are optional.

Upvotes: 2

Matt Wilko
Matt Wilko

Reputation: 27342

Instead of using many optional parameters you could just pass an Object (Class) that has properties with a default value. That way it can work the same as optional parameters:

Public Class Parameters

    Public Property Name As String = "Undefined"
    Public Property Country as string = "United Kingdom"

End Class

Define your WebMethod to accept this object type

Public Function WebMethod(prm as Parameters)

Usage:

Pass parameters with a Name:

WebMethod(New Parameters With {.Name = "Jane"})

Pass Parameters with a Name and Country:

WebMethod(New Parameters With {.Name = "Amr", .Country = "Egypt"})

Pass Parameters with just Country:

WebMethod(New Parameters With {.Country = "China"})

Upvotes: 3

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