Adding operations to WCF service on runtime

gistfile1.cs

public static OperationDescription[] AddHelpOperations(ContractDescription contractDescription, DispatchRuntime dispatchRuntime)
{
    Fx.Assert(contractDescription != null, "The 'contractDescription' parameter should not be null.");
    Fx.Assert(dispatchRuntime != null, "The 'dispatchRuntime' parameter should not be null.");

    Uri baseAddress = dispatchRuntime.EndpointDispatcher.EndpointAddress.Uri;
    HelpPage helpPage = new HelpPage(baseAddress, null, contractDescription);

    HttpOperationDescription helpPageOperation = new HttpOperationDescription(HelpPage.HelpMethodName, contractDescription);
    helpPageOperation.Behaviors.Add(new WebGetAttribute() { UriTemplate = HelpPage.OperationListHelpPageUriTemplate });
    helpPageOperation.InputParameters.Add(HttpParameter.RequestMessage);
    helpPageOperation.ReturnValue = HttpParameter.ResponseMessage;

    HttpOperationDescription operationhelpPageOperation = new HttpOperationDescription(HelpPage.HelpOperationMethodName, contractDescription);
    operationhelpPageOperation.Behaviors.Add(new WebGetAttribute() { UriTemplate = HelpPage.OperationHelpPageUriTemplate });
    operationhelpPageOperation.InputParameters.Add(HttpParameter.RequestMessage);
    operationhelpPageOperation.InputParameters.Add(new HttpParameter("operation", TypeHelper.StringType));
    operationhelpPageOperation.ReturnValue = HttpParameter.ResponseMessage;

    dispatchRuntime.Operations.Add(
        new DispatchOperation(dispatchRuntime, HelpPage.HelpMethodName, null, null) { Invoker = helpPage.GetHelpPageInvoker(true) });
    dispatchRuntime.Operations.Add(
        new DispatchOperation(dispatchRuntime, HelpPage.HelpOperationMethodName, null, null) { Invoker = helpPage.GetHelpPageInvoker(false) });

    return new OperationDescription[] { helpPageOperation.ToOperationDescription(), operationhelpPageOperation.ToOperationDescription() };
}