Consume SOAP API in C#

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C#

SOAP

I try to consume a SOAP api in C#. The code is compiled but when I run it, the following message appears:

<pre>System.InvalidOperationException
  HResult=0x80131509
  Message=Unable to generate a temporary class (result=1).
error CS0029: Cannot implicitly convert type 'string' to 'string[]'

  Source=System.Xml
  StackTrace:
   at System.Xml.Serialization.Compiler.Compile(Assembly parent, String ns, XmlSerializerCompilerParameters xmlParameters, Evidence evidence)
   at System.Xml.Serialization.TempAssembly.GenerateAssembly(XmlMapping[] xmlMappings, Type[] types, String defaultNamespace, Evidence evidence, XmlSerializerCompilerParameters parameters, Assembly assembly, Hashtable assemblies)
   at System.Xml.Serialization.TempAssembly..ctor(XmlMapping[] xmlMappings, Type[] types, String defaultNamespace, String location, Evidence evidence)
   at System.Xml.Serialization.XmlSerializer.GetSerializersFromCache(XmlMapping[] mappings, Type type)
   at System.Xml.Serialization.XmlSerializer.FromMappings(XmlMapping[] mappings, Type type)
   at System.Web.Services.Protocols.SoapClientType..ctor(Type type)
   at System.Web.Services.Protocols.SoapHttpClientProtocol..ctor()
   at SOAPapi.Textkernel.SearchServiceService..ctor() in C:\Users\VanTol\Documents\Projects\CSharp\SOAPapi\SOAPapi\Web References\Textkernel\Reference.cs:line 45
   at SOAPapi.Program.Main(String[] args) in C:\Users\VanTol\Documents\Projects\CSharp\SOAPapi\SOAPapi\Program.cs:line 23

I checked all the parameter types and in the IDE they are correct.Does anybody have an idea what is going wrong?

The error occurs at codeline:

SearchServiceService client = new SearchServiceService();

What I have tried:

I created a C# console project and added the API as Web reference.
This is the wsdl: href="https://staging.textkernel.nl/SearchBox/soap/search?wsdl

This is the code:

static void Main(string[] args)
        {
            string ENVIRONMENT = "my_environment";
            string PASSWORD = "myPassword";
            string[] ACCESSROLES = new string[1];
            string LANGUAGE;
            accessOptions ACCESSOPTIONS = new accessOptions();
            searchRequest SEARCHREQUEST = new searchRequest();
            searchResult SEARCHRESULT = new searchResult();
            compositeMetadata METADATA = new compositeMetadata();
            userOptions USEROPTIONS = new userOptions();
            SearchServiceService client = new SearchServiceService();
            


            ACCESSROLES[0] = "all";
            LANGUAGE = "NL";
            
            METADATA = client.getMetadata(ENVIRONMENT, PASSWORD, ACCESSOPTIONS, LANGUAGE, USEROPTIONS, ACCESSROLES);

            Console.ReadKey();
        }