Simple SOAP Example in C#

Question

I am experimenting with creating a SOAP connection to Salesforce using C#. I am using the sample code in SOAP API Developer Guide (PDF pages 22-28). It says it uses "A .NET 3.0 style reference uses services like SoapClient". I assume it was referring to the SOAPClient in Microsoft.Web.Services3. When I try to instance a SoapClient it gives the error "can't create an instance from an abstract class or interface". I added a Service Reference to the WSDL file and that worked.

Questions:

• Does anyone have any ideas on why it can't instance it? (Docs show it should work)
• Does anyone have this example working? Can you share it?

Thanks.

Code:

using System;
using System.ServiceModel;
using Microsoft.Web.Services3.Messaging;
using SimpleConnect.SFProd;  // WSDL XML File

namespace SimpleConnect
{
class SimpleConnect
{
    private static SoapClient loginClient; // for login endpoint
....
    static void Main(string[] args)
    {
        SimpleConnect sample = new SimpleConnect();
......
        loginClient = new SoapClient();    //************************** Error

Answer 1

The key is in the previous step of the SalesForce SOAP API Quick Start.

You can add either a .NET 2.0 style Web reference, or a .NET 3.0 style Service reference, depending on your version of Visual Studio and preferred developer environment. A .NET 3.0 style reference uses services like SoapClient instead of SforceService. (emphasis mine)

The following section of that page details adding a web reference, but offers no guidance for adding a service reference. It's even easier than adding a web reference.

1. Generate Your WDSL

Browse to your Salesforce.com instance and generate a WSDL file (same as in the Salesforce docs).

2. Add a Service Reference

I'm using Visual Studio 2017. This is what the process looks like for me.

Note that I had to set the namespace to "sForce".

3. Add a Using Statement

The namespace of the Salesforce reference is placed inside the project reference. As you can see, there's no compile error for my reference to SoapClient, which was provided in the sForce namespace.

Since the documentation gives example code for the newer service reference, it should really include instructions to set up the service reference. But hey, they're pretty good docs overall, so I guess it's fine.

Do note that there's a performance impact to using the service instead of the web reference.

Also note I had to use a workaround to avoid a bug in how the reference is generated from WSDL. It's described quite well in another answer.

4. Use the Service

Once the service is set up, you can use code from the Salesforce tutorial to log in (copied here with slight modifications):

public class SfSession
{
    public static SoapClient client;
    private static SoapClient loginClient;
    private static SessionHeader sessionHeader;
    private static EndpointAddress endpoint;

    public bool Login()
    {
        string username = "<EMAIL>";
        string password = "<PASSWORD>(<TOKEN>)";

        loginClient = new SoapClient();

        ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
        LoginResult lr = loginClient.login(null, username, password);

        endpoint = new EndpointAddress(lr.serverUrl);

        sessionHeader = new SessionHeader
        {
            sessionId = lr.sessionId
        };

        client = new SoapClient("Soap", endpoint);

        return true;
    }

    private void Logout()
    {
        client.logout(sessionHeader);
    }
}

(btw, don't leave your username/password in code... I put it there solely for testing)

Answer 2

C# has a SOAP bug with a WSDL. I vaguely remember that everything needs an attribute being the cause. Bug information is listed below. You can edit your WSDL to the following to fix the issue:

Before:

<complexType name="ListViewRecord">
  <sequence>
   <element name="columns" type="tns:ListViewRecordColumn" maxOccurs="unbounded"/>
  </sequence>
</complexType>

<complexType name="ListViewRecordColumn">
<sequence>
  <element name="fieldNameOrPath" type="xsd:string"/>
  <element name="value" type="xsd:string" nillable="true"/>
</sequence>
</complexType>

After:

<complexType name="ListViewRecord">
  <sequence>
   <element name="columns" type="tns:ListViewRecordColumn" maxOccurs="unbounded"/>
  </sequence>
  <xsd:attribute name="tmp" type="xsd:string" />
</complexType>

<complexType name="ListViewRecordColumn">
<sequence>
  <element name="fieldNameOrPath" type="xsd:string"/>
  <element name="value" type="xsd:string" nillable="true"/>
</sequence>
<xsd:attribute name="tmp" type="xsd:string" />
</complexType>

Update:

Found the Bug Information:

XmlSerializer Code Generation component cannot handle nested unbounded elements when there is only one element

Salesforce Support on the Issue

Answer 3

The quick fix that I use is to create the web service in C# and then edit the Reference.cs file under Reference.map.

Search for ListViewRecordColumn then change the following:

private ListViewRecordColumn[][] recordsField; and public ListViewRecordColumn[][] records

to

private ListViewRecordColumn[] recordsField; and public ListViewRecordColumn[] records