WCF AJAX Service Without Configuration

This post discusses how to develop Windows Communication Foundation (WCF) service using AJAX and without any configuration settings for WCF. This service can be consumed from Javascript. The service uses a special setting in .svc file which automatically enables an AJAX endpoint.

You can get the AJAX support for WCF through the ScriptManager control.

1. Create a WCF service project in VS 2010

The service contract code as follows

   1: // Define a service contract.

   2:   [ServiceContract(Namespace = "ConfigFreeWCFAjaxService")]

   3:   public interface ICalculator

   4:   {

   5:       [OperationContract]

   6:       double Add(double n1, double n2);

   7:   }

Service Implementation code as follows

   1: public class CalculatorService : ICalculator

   2: {

   3:     public double Add(double n1, double n2)

   4:     {

   5:         return n1 + n2;

   6:     }

   7: }

The SVC file setting as below

   1: <%@ServiceHost 

   2:     language="c#"

   3:     Debug="true"

   4:     Service="ConfigFreeWCFAjaxService.CalculatorService"

   5:     Factory="System.ServiceModel.Activation.
          WebScriptServiceHostFactory" 

   6: %>

   1: <asp:ScriptManager ID="ScriptManager" runat="server">

   2:     <Services>

   3:         <asp:ServiceReference Path="service.svc" />

   4:     </Services>

   5: </asp:ScriptManager>

Calling the service from javascript

<script type="text/javascript">

  function makeAJAXCall()

   {

   var n1 = document.getElementById("num1").value;

   var n2 = document.getElementById("num2").value;

   // Instantiate a service proxy

   var proxy = new  ConfigFreeWCFAjaxService.ICalculator();

  // Call correct operation on proxy      
  proxy.Add(parseFloat(n1), parseFloat(n2), onSuccess, onFail, null);           
  break;

  }

</script>

    function onSuccess(mathResult)

     {

        document.getElementById("result").value = mathResult;

    }

The <system.ServiceModel> element can be completely removed from the web.config if you configure your service as shown in the above.