Generate a WCF client proxy for a netstandard Xamarin.Forms project

Question

I've created a Xamarin.Forms project with a netstandard2.0 targeting library instead of a shared or PCL library. So far this compiles and works. I'm using an up2date version of Visual Studio 2017 Community.

I also have created a WCF service that gonna be hosted on windows itself (not IIS). I've configured my app.config to provide a Metadata Exchange Endpoint:

<?xml version="1.0"?>
<configuration>
    <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
    </startup>
    <system.serviceModel>
        <services>
            <service behaviorConfiguration="MM.Server.ServiceServerBehavior" name="MM.Server.ServiceServer">
                <endpoint address="net.tcp://localhost:8730/MMServer/" binding="netTcpBinding" bindingConfiguration="NetTcpBinding_IServiceServer" bindingName="NetTcpBinding_IServiceServer_EndPoint" contract="MM.Contracts.IServiceServer">
                    <identity>
                        <dns value="localhost"/>
                    </identity>
                </endpoint>
                <endpoint address="http://localhost:8731/MMServer/mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
                <host>
                    <baseAddresses>
                        <add baseAddress="net.tcp://localhost:8730/MMServer/"/>
                    </baseAddresses>
                </host>
            </service>
        </services>
        <behaviors>
            <serviceBehaviors>
                <behavior name="MM.Server.ServiceServerBehavior">
                    <serviceMetadata httpGetEnabled="true" httpGetUrl="http://localhost:8731/MMServer/mex" />
                    <serviceDebug includeExceptionDetailInFaults="true"/>
                </behavior>
            </serviceBehaviors>
        </behaviors>
        <bindings>
            <netTcpBinding>
                <binding name="NetTcpBinding_IServiceServer" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" transactionFlow="false" transferMode="Buffered" transactionProtocol="OleTransactions" hostNameComparisonMode="StrongWildcard" listenBacklog="10" maxBufferPoolSize="2147483647" maxBufferSize="2147483647" maxConnections="10" maxReceivedMessageSize="2147483647">
                    <readerQuotas maxDepth="32" maxStringContentLength="2147483647" maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="16384"/>
                    <reliableSession ordered="true" inactivityTimeout="01:00:00" enabled="false"/>
                    <security mode="None"><!-- TODO: Add more security later -->
                        <transport clientCredentialType="None" protectionLevel="None"/>
                    </security>
                </binding>
            </netTcpBinding>
        </bindings>
    </system.serviceModel>
</configuration>

This is a very simple configuration and I don't care about security for now. The service runs, successfully.

Now I cannot simply add a service reference to my Xamarin.Forms project, since netstandard does not provide System.ServiceModel.

I've found out that I can use the SLsvcUtil.exe from the Silverlight SDK to generate the client proxy for my WCF service that is compatible to Xamarin.Forms targeting netstandard instead, however I cannot get it running.

No matter how I try to use the SLsvcUtil.exe while my WCF service is running, I always get the error:

Error: An error occurred in the tool.
Error: Object reference not set to an instance of an object.

Here is my batch that I used to execute SLsvcUtil.exe:

set "namespace=*,MM.Services"
set "mexPath=http://localhost:8731/MM/mex"
set "svcutil=C:\Program Files (x86)\Microsoft SDKs\Silverlight\v5.0\Tools\SLsvcUtil.exe"
set "outputDir=C:\vsproj\Xamarin\MM\MM.App"
"%svcutil%" %mexPath% /directory:"%outputDir%" /namespace:"%namespace%"
pause

http://localhost:8731/MM/mex returns the full WSDL, successfully.

How can I get a working generated client proxy for my Xamarin.Forms app that is targeting netstandard2.0? I'm open for any alternative that leads to the same desired result.

Answer 1

Take a look at the official Microsoft WCF client for .NET Core. I think this should work also with Xamarin since it is designed for .NET Core.

GitHub .NET Core WCF Client Libraries

Web Service Reference guide

Microsoft WCF Web Service Reference Provider