<ServiceContract()>  _
Public Interface ICalculatorService
    <OperationContract()>  _
    Function Add(ByVal n1 As Double, ByVal n2 As Double) As Double 
    '<OperationContract()>  _
    Function Subtract(ByVal n1 As Double, ByVal n2 As Double) As Double
End Interface


Public Class CalculatorService
    Implements ICalculatorService

    Public Function Add(ByVal n1 As Double, ByVal n2 As Double) As Double Implements ICalculatorService.Add
        Return n1 + n2

    End Function

    Public Function Subtract(ByVal n1 As Double, ByVal n2 As Double) As Double Implements ICalculatorService.Subtract
        Return n1 - n2

    End Function
End Class

[ServiceContract()]
public interface ICalculatorService
{
    [OperationContract]
    double Add(double n1, double n2);
    [OperationContract]
    double Subtract(double n1, double n2);
}

public class CalculatorService : ICalculatorService
{
    public double Add(double n1, double n2) { return n1 + n2; }
    public double Subtract(double n1, double n2) { return n1 - n2; }
}

Public Function Add(ByVal n1 As Double, ByVal n2 As Double) As Double Implements ICalculatorService.Add
    Return System.Convert.ToDouble(MyBase.Call("Add", "https://fabrikam.com/CalcService/ICalculatorService/Add", New String() {"n1", "n2"}, New Object() {n1, n2}, GetType(Double)))

End Function

public double Add(double n1, double n2)
{
    return (double)base.Call("Add", "https://fabrikam.com/CalcService/ICalculatorService/Add", new string[] { "n1", "n2" }, new object[] { n1, n2 }, typeof(double));
}

Public Class ClientBase(Of TChannel As Class)

    Private requestChannel As IRequestChannel
    Private messageVersion As MessageVersion


    Public Sub New(ByVal binding As System.ServiceModel.Channels.Binding, ByVal remoteAddress As System.ServiceModel.EndpointAddress)
        'this.remoteAddress = remoteAddress;
        Me.messageVersion = binding.MessageVersion

        Dim parameters = New System.ServiceModel.Channels.BindingParameterCollection()

        ' Specifies the X.509 certificate used by the client.
        Dim cc As New ClientCredentials()
        cc.ClientCertificate.SetCertificate(StoreLocation.CurrentUser, StoreName.My, X509FindType.FindBySubjectName, "testuser")
        parameters.Add(cc)

        Dim channelFactory As IChannelFactory(Of IRequestChannel)
        channelFactory = binding.BuildChannelFactory(Of IRequestChannel)(parameters)
        channelFactory.Open()
        Me.requestChannel = channelFactory.CreateChannel(remoteAddress)

    End Sub


    Public Function [Call](ByVal op As String, ByVal action As String, ByVal varnames() As String, ByVal varvals() As Object, ByVal returntype As Type) As Object
        requestChannel.Open(TimeSpan.MaxValue)

        'Message msg =
        'Message.CreateMessage(MessageVersion.<FromBinding>,
        '      action,
        '      new CustomBodyWriter(op, varnames, varvals,
        '"<ns passed in from Proxy>"));
        Dim msg As Message = Message.CreateMessage(Me.messageVersion, action, New CustomBodyWriter(op, varnames, varvals, "<ns passed in from Proxy>"))

        Dim reply As Message = requestChannel.Request(msg, TimeSpan.MaxValue)
        Dim reader As XmlDictionaryReader = reply.GetReaderAtBodyContents()
        reader.ReadToFollowing(op + "Result")
        Return reader.ReadElementContentAs(returntype, Nothing)

    End Function
End Class


Friend Class CustomBodyWriter
    Inherits BodyWriter
    Private op As String
    Private varnames() As String
    Private varvals() As Object
    Private ns As String


    Public Sub New(ByVal op As String, ByVal varnames() As String, ByVal varvals() As Object, ByVal ns As String)
        MyBase.New(True)
        Me.op = op
        Me.varnames = varnames
        Me.varvals = varvals
        Me.ns = ns

    End Sub


    Protected Overrides Sub OnWriteBodyContents(ByVal writer As XmlDictionaryWriter)
        writer.WriteStartElement(op, ns)
        Dim i As Integer
        For i = 0 To varnames.Length
            writer.WriteElementString(varnames(i), varvals(i).ToString())
        Next i
        writer.WriteEndElement()

    End Sub
End Class

public class ClientBase<TChannel>
    where TChannel : class
{
    private IRequestChannel requestChannel;
    private MessageVersion messageVersion;

    public ClientBase(System.ServiceModel.Channels.Binding binding, System.ServiceModel.EndpointAddress remoteAddress)
    {
        //this.remoteAddress = remoteAddress;
        this.messageVersion = binding.MessageVersion;

        BindingParameterCollection parameters = new System.ServiceModel.Channels.BindingParameterCollection();

        // Specifies the X.509 certificate used by the client.
        ClientCredentials cc = new ClientCredentials();
        cc.ClientCertificate.SetCertificate(StoreLocation.CurrentUser, StoreName.My, X509FindType.FindBySubjectName, "testuser");
        parameters.Add(cc);

        IChannelFactory<IRequestChannel> channelFactory = binding.BuildChannelFactory<IRequestChannel>(
            parameters);
        channelFactory.Open();
        this.requestChannel = channelFactory.CreateChannel(remoteAddress);
    }

    public object Call(string op, string action, string[] varnames, object[] varvals, Type returntype)
    {
        requestChannel.Open(TimeSpan.MaxValue);

        //Message msg =
        //Message.CreateMessage(MessageVersion.<FromBinding>,
        //      action,
        //      new CustomBodyWriter(op, varnames, varvals,
        //"<ns passed in from Proxy>"));

        Message msg =                     
        Message.CreateMessage(this.messageVersion, action,
              new CustomBodyWriter(op, varnames, varvals,                 
        "<ns passed in from Proxy>"));

        Message reply = requestChannel.Request(msg, TimeSpan.MaxValue);
        XmlDictionaryReader reader = reply.GetReaderAtBodyContents();
        reader.ReadToFollowing(op + "Result");
        return reader.ReadElementContentAs(returntype, null);
    }

}

internal class CustomBodyWriter : BodyWriter
{
    private string op;
    private string[] varnames;
    private object[] varvals;
    private string ns;

    public CustomBodyWriter(string op, string[] varnames, object[] varvals, string ns)
        : base(true)
    {
        this.op = op;
        this.varnames = varnames;
        this.varvals = varvals;
        this.ns = ns;
    }

    protected override void OnWriteBodyContents(XmlDictionaryWriter writer)
    {
        writer.WriteStartElement(op, ns);
        for (int i = 0; i < varnames.Length; i++)
            writer.WriteElementString(varnames[i], varvals[i].ToString());
        writer.WriteEndElement();
    }
}

Class Program

    ''' <summary>
    ''' The main entry point for the application.
    ''' </summary>
    <MTAThread()> _
    Shared Sub Main()

        Dim serverAddress As String = CalculatorServiceClient.ServiceEndPoint.Uri.AbsoluteUri

        Dim binding As New BasicHttpBinding()

        ' Specifies transport security over HTTPS and the use of a
        ' client certificate for authentication.
        binding.Security.Mode = BasicHttpSecurityMode.Transport
        binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Certificate

        Dim proxy = New CalculatorServiceClient(binding, New EndpointAddress(serverAddress))

        MessageBox.Show("Add 3 + 6...")
        MessageBox.Show(proxy.Add(3, 6).ToString())
        MessageBox.Show("Subtract 8 - 3...")
        MessageBox.Show(proxy.Subtract(8, 3).ToString())

    End Sub
End Class

static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [MTAThread]

    static void Main()
    {
        string serverAddress = CalculatorServiceClient.ServiceEndPoint.Uri.AbsoluteUri;

        BasicHttpBinding binding = new BasicHttpBinding();

        // Specifies transport security over HTTPS and the use of a
        // client certificate for authentication.
        binding.Security.Mode = BasicHttpSecurityMode.Transport;
        binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Certificate;

        ICalculatorService proxy = new CalculatorServiceClient(binding, new EndpointAddress(serverAddress));

        MessageBox.Show("Add 3 + 6...");
        MessageBox.Show((proxy.Add(3, 6)).ToString());
        MessageBox.Show("Subtract 8 - 3...");        
        MessageBox.Show((proxy.Subtract(8, 3)).ToString());

    }
}