Cheers Greg, some useful info there. We are embarcking on a Silverlight
project ourselves soon, so this will come in handy! ;-)
Steve
On 13 June 2010 23:27, Greg Keogh <g...@mira.net> wrote:
> Hi Stephen, it looks like an later message of mine may have got lost. I
> accidentally found that my worry about WCF behaviours was wasted, as many
> WCF interfaces are not supported on the Silverlight client. I stumbled over
> an article that pointed I have to do the following (simplified real code).
> The code is a bit obtuse because I had to use Action callback combined
> with using to keep the OperationContext open while methods are called. I
> hope this skeleton code might be of use to others who have to pass arbitrary
> extra data from a WCF client to the service. The key bits are:
>
>
>
> · The method CallWrapper on the client puts a header into the
> client proxy. I have to use this wrapper on each call and it has to be
> wrapped in a using.
>
> · The method GetHeaderValue<> on the server pulls header values
> out of the current context. It’s interesting that it’s generic and you can
> get strongly typed values.
>
>
>
> Cheers,
>
> Greg
>
>
>
>
>
> *Sliverlight Client*
>
>
>
> public void SampleSeviceCall(int xmlToken, Action<bool, Exception,
> SampleResultWrapper> callback)
>
> {
>
> using (var client = MakeClient())
>
> {
>
> client.Proxy.SampleSeviceCallCompleted += (s, e) =>
>
> {
>
> callback(e.Cancelled, e.Error, e.Result);
>
> };
>
> CallWrapper(client, () => {
> client.Proxy.SampleSeviceCallAsync(xmlToken); });
>
> }
>
> }
>
>
>
> private void CallWrapper(SafeClient<AggregationClient, IAggregationService>
> client, Action callback)
>
> {
>
> using (OperationContextScope ocs = new OperationContextScope
> (client.Proxy.InnerChannel))
>
> {
>
> OperationContext.Current.OutgoingMessageHeaders.Add(
>
> MessageHeader.CreateHeader("secretId", "MyNamespace",
> secretId));
>
> callback();
>
> }
>
> }
>
>
>
> *WCF Service*
>
>
>
> public SampleResultWrapper SampleServiceMethod(int xmlToken)
>
> {
>
> Guid secretId = GetHeaderValue<Guid>("secretId");
>
> SampleResultWrapper result = new SampleResultWrapper();
>
> try
>
> {
>
> result.SomeXml = GetTheXml(xmlToken);
>
> }
>
> catch (Exception ex)
>
> {
>
> result.Error = ex;
>
> }
>
> return result;
>
> }
>
>
>
> private T GetHeaderValue<T>(string name)
>
> {
>
> int index =
> OperationContext.Current.IncomingMessageHeaders.FindHeader(name,
> " MyNamespace ");
>
> return (index >= 0 ?
>
> OperationContext.Current.IncomingMessageHeaders.GetHeader<T>(index)
> :
>
> default(T));
>
> }
>
>
>
>
>
>
>
