WCF WebService Not Returning DataTable - wcf

Question

I am beginning to use WCF to write a web service instead of the old asp.net asmx way. I want to be able to return JSON so I can't do it the old way. If I am returning a string or int the Web Service works fine but if I try to return a DataTable it becomes unresponsive and I get nothing. I have tried debugging to see where it blows up and it won't even stop on a breakpoint.
My Class file looks like this:
public string XMLData(string id)
{
return "You requested " + id;
}
public string JSONData(string id)
{
return "You requested " + id;
}
public DataTable TestDT()
{
DataTable Testing = new DataTable("TestDT");
return Testing;
}
My interface file looks like this:
[OperationContract]
[WebInvoke(Method = "GET", ResponseFormat = WebMessageFormat.Xml, BodyStyle = WebMessageBodyStyle.Wrapped,
UriTemplate = "xml/{id}")]
string XMLData(string id);
[OperationContract]
[WebInvoke(Method = "GET", ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Wrapped,
UriTemplate = "json/{id}")]
string JSONData(string id);
[OperationContract]
[WebInvoke(Method = "GET", ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Wrapped,
UriTemplate = "testdt/")]
DataTable TestDT();
The json method as well as the xml method works perfectly fine. When I call TestDT I get a standard IE Page showing no connectivity. I have tried it with data or no data in the datable with the same results.
One other note here: when I run the WCF service locally (Hitting PLAY) my test application shows now services I see this:
How can I get this to work with a datable?
Edit#1: I actually resolved the issue with the data not returning. I finally gave up on trying to return a dataset and instead I created a jagged array and ended up return it as JSON. I'll post it later as an answer so people know how I did it. What I am more interested in knowing now is part 2. Why is my WCF Test Client not showing any methods (see image attached) My hunch is its related to the web.config so I am posting that below:
<?xml version="1.0"?>
<configuration>
<connectionStrings>
<add name="DBDjuggleWS" connectionString="Data Source=localhost;Initial Catalog=PrayUpDev;Persist Security Info=True;User=DjuggleMaster;Password=DJPassword!" providerName="System.Data.SqlClient"/>
</connectionStrings>
<system.web>
<compilation debug="true" targetFramework="4.0" />
</system.web>
<system.serviceModel>
<services>
<service name ="PrayUpService.PrayUp" behaviorConfiguration="ServiceBehaviour">
<endpoint address="" binding="webHttpBinding" contract="PrayUpService.IPrayUp" behaviorConfiguration ="web"></endpoint>
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior name="ServiceBehaviour">
<!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->
<serviceMetadata httpGetEnabled="true"/>
<!-- To receive exception details in faults for debugging purposes, set the value below to true. Set to false before deployment to avoid disclosing exception information -->
<serviceDebug includeExceptionDetailInFaults="true"/>
</behavior>
</serviceBehaviors>
<endpointBehaviors>
<behavior name="web">
<webHttp/>
</behavior>
</endpointBehaviors>
</behaviors>
<serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
</system.serviceModel>
<system.webServer>
<modules runAllManagedModulesForAllRequests="true"/>
</system.webServer>
</configuration>

Answer 1

you shoud return DataSet instead of DataTable but Returning data sets from web services is not typically considered a “good practice”. here you can read about it:
Why returning dataset or data table from WCF service is not a good practice? What are the Alternatives?
i highly recommend use the DataSet’s methods to get the data in XML format and pass the XML string instead of the DataSet itself to the service.
PassDataSet(dsDataSet.GetXmlSchema(), dsDataSet.GetXml())