R – Error when calling the service in async mode

asynchronous-wcf-callidictionarywcf

Stackoverflow is definetly the fastest forum so after posting this question in the WCF forum I decided to come here.

I have a wcf service which returns a dictionary (IDictionary) and that works just fine. Now I wanted to add the capability of calling that service in async mode, but when the BeginMethod gets executed I get the following Exception:

The type
System.Collections.Generic.Dictionary`2[[System.String,
mscorlib, Version=2.0.0.0,
Culture=neutral,
PublicKeyToken=b77a5c561934e089],[TransferProp,
Contracts, Version=10.1.0.0,
Culture=neutral,
PublicKeyToken=6f5bf81c27b6b8aa]] is
not supported because it implements
IDictionary.

What's up with that?

Best Answer

This (CodeIdol) blog talks about deriving your own CollectionDataContract collection and returning this. Does this help?

[CollectionDataContract]
public class MyDictionary : Dictionary<int,Contact>
{}

[ServiceContract]
interface IContactManager
{
   ...
   [OperationContract]
   MyDictionary GetContacts( );
}

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Does your WCF client set the required "allowed impersonation level":

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <system.serviceModel>

        <!-- .... -->

        <behaviors>
           <endpointBehaviors>
              <behavior name="ImpersonationBehavior">
                 <clientCredentials>
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                 </clientCredentials>
              </behavior>
           </endpointBehaviors>
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    </system.serviceModel>
</configuration>

By default this is set to Identification if nothing is specified explicitly. Check out this blog post for more info.

Wcf – Getting NullReferenceException when calling WCF service from client

It turns out that I had some properties tagged as [DataMember] that had getters but no setters.

Usually, I'd get a descriptive error by looking at the trace file on the service, or in a pop-up window when adding the service reference on the client project. This time around I did not.

I had to search for ALL instances of [DataMember] and looked at them one by one to find the properties that were missing a setter.

Best Answer

Related Solutions

.net – Why, when I impersonate within a WCF service, can the service not load System.Transactions when I try to run a LINQ to SQL query

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