Call a Web Service Without Adding a Web Reference

askaslam

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11 Sep 2009CPOL

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Calling a Web Service without adding a web reference

Introduction

A client requested that for some reason he cannot add a Web Reference and wanted to specify the web service URL in web.config or hardcode it. Hence, my first article:)

Background

I did create this source more than a year ago. I used the internet to get information/ideas regarding this.

I am copying from my blog.

Using the Code

Create a class as with "DynamicWebService" and new method "CallWebService".
Create an object of this class and call method "CallWebService" with web service URL and other parameters:

VB.NET

Imports System.CodeDom
Imports System.CodeDom.Compiler
Imports System.Security.Permissions
Imports System.Web.Services.Description
Imports System.Reflection

Public Function CallWebService(ByVal webServiceAsmxUrl As String, _
       ByVal serviceName As String, ByVal methodName As String, _
       ByVal args() As Object) As Object

    Try
    Dim client As System.Net.WebClient = New System.Net.WebClient()

    '-Connect To the web service
    Dim stream As System.IO.Stream = _
        client.OpenRead(webServiceAsmxUrl + "?wsdl")

    'Read the WSDL file describing a service.
    Dim description As ServiceDescription = ServiceDescription.Read(stream)

    'LOAD THE DOM'''''''''''''''''''''''''''

    '--Initialize a service description importer.
    Dim importer As ServiceDescriptionImporter = New ServiceDescriptionImporter()
    importer.ProtocolName = "Soap12" ' Use SOAP 1.2.
    importer.AddServiceDescription(description, Nothing, Nothing)

    '--Generate a proxy client. 

    importer.Style = ServiceDescriptionImportStyle.Client
    '--Generate properties to represent primitive values.
    importer.CodeGenerationOptions = _
         System.Xml.Serialization.CodeGenerationOptions.GenerateProperties

    'Initialize a Code-DOM tree into which we will import the service.
    Dim nmspace As CodeNamespace = New CodeNamespace()
    Dim unit1 As CodeCompileUnit = New CodeCompileUnit()
    unit1.Namespaces.Add(nmspace)

    'Import the service into the Code-DOM tree. 
    'This creates proxy code that uses the service.

    Dim warning As ServiceDescriptionImportWarnings = _
                   importer.Import(nmspace, unit1)

    If warning = 0 Then

            '--Generate the proxy code
            Dim provider1 As CodeDomProvider = _
                      CodeDomProvider.CreateProvider("VB")
            '--Compile the assembly proxy with the // appropriate references
            Dim assemblyReferences() As String
            assemblyReferences = New String() {"System.dll", _
                "System.Web.Services.dll", "System.Web.dll", _
                "System.Xml.dll", "System.Data.dll"}
        	Dim parms As CompilerParameters = New CompilerParameters(assemblyReferences)
	parms.GenerateInMemory = True '(Thanks for this line nikolas)
        	Dim results As CompilerResults = provider1.CompileAssemblyFromDom(parms, unit1)

        '-Check For Errors
        If results.Errors.Count > 0 Then

            Dim oops As CompilerError
            For Each oops In results.Errors
                System.Diagnostics.Debug.WriteLine("========Compiler error============")
                System.Diagnostics.Debug.WriteLine(oops.ErrorText)
            Next
            Throw New System.Exception("Compile Error Occurred calling webservice.")
        End If

        '--Finally, Invoke the web service method
        Dim wsvcClass As Object = results.CompiledAssembly.CreateInstance(serviceName)
        Dim mi As MethodInfo = wsvcClass.GetType().GetMethod(methodName)
        Return mi.Invoke(wsvcClass, args)

    Else
        Return Nothing
    End If

    Catch ex As Exception
    Throw ex
    End Try
End Function

Calling

Call this web service in a Webform or windows form or method, etc... as shown below:

VB.NET

Dim WebserviceUrl As String = _
"http://www.abc.com/lgl/test/webservice/v1_00/security.asmx"

'specify service name
Dim serviceName As String = "SecurityAndSessionManagement"

'specify method name to be called
Dim methodName As String = "Session_Start"

'Arguments passed to the method
Dim arArguments(1) As String
arArguments(0) = "abc"
arArguments(1) = "xxxx"

Dim objCallWS As New DynamicWebService
sSessionID = objCallWS.CallWebService(WebserviceUrl, serviceName, _
                                      methodName, arArguments)
MsgBox("new SessionID: " & sSessionID)

History

11^th September, 2009: Initial post

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By

askaslam

United Kingdom

This member has not yet provided a Biography. Assume it's interesting and varied, and probably something to do with programming.

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