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I have a C# / WPF project that references a webservice. However, sometimes I get a NullReferenceException when creating an instance of the auto-generated class that represents it:

var service = new SSO();

The stacktrace is as follows:

System.NullReferenceException: Object reference not set to an instance of an object.
    in System.Xml.Serialization.XmlSerializer.GetSerializersFromCache(XmlMapping[] mappings, Type type)
    in System.Xml.Serialization.XmlSerializer.FromMappings(XmlMapping[] mappings, Type type)
    in System.Web.Services.Protocols.SoapClientType..ctor(Type type)
    in System.Web.Services.Protocols.SoapHttpClientProtocol..ctor()
    in MyNamespace.SSO..ctor()

Does anyone have an idea what's going on here? The server may have small periods of downtime, but that's not the exception I expect to see in case of network connection issues!

Update: the code of the auto-generated class SSO in case someone finds it relevant:

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Web.Services", "4.0.30319.17929")]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Web.Services.WebServiceBindingAttribute(Name="SSOSoap", Namespace="http://schemas.example.com/SSO")]
public partial class SSO : System.Web.Services.Protocols.SoapHttpClientProtocol
{
    public SSO()
    {
        this.Url = "http://example.com/SSO.asmx";
        if ((this.IsLocalFileSystemWebService(this.Url) == true))
        {
            this.UseDefaultCredentials = true;
            this.useDefaultCredentialsSetExplicitly = false;
        }
        else
        {
            this.useDefaultCredentialsSetExplicitly = true;
        }
    }

    // a lot of methods here
}
Impworks
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    Post the constuctor for `SSO` – p.s.w.g Apr 11 '13 at 12:57
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    SSO is the auto-generated class created by Visual Studio when I add a web reference. The actual code is not releavant, because `SSO` inherits from `SoapHttpClientProtocol` and the base constructor is called before any code can execute. – Impworks Apr 11 '13 at 12:58
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    "_The actual code is not relevant_" ... if I had a nickle for every time I'd heard that ;-) – Wim Ombelets Apr 11 '13 at 13:20
  • @WimOmbelets, I've added a snippet of code in case it may clarify anything and give you an idea. – Impworks Apr 11 '13 at 13:31
  • This won't help your problem, but a little note on style: `== true` in an `if` statement is always redundant. – Rik Apr 15 '13 at 11:38
  • @Rik, this code has been generated by Visual Studio. It does a lot of redundant stuff. – Impworks Apr 18 '13 at 13:55

0 Answers0