HTTP POST XML to REST Singleton Service throws NotSupportedException

Question

I have the following REST Host in a silverlight application. I'm getting a NotSupportedException on the EndGetResponse() call of the Save Method. In this sample I'm using the default config for a REST Singleton Service from the WCF REST Starter Kit, with the exception of some changes to the OnAddItem method to accept updates via a POST (since silverlight PUT isn't supported). I'm getting a StatusCode 200 when I make a post from Fiddler. The Service is hosted on the same site as the SilverlightPage, so I don't have any x-domain policy stuff setup. Am I missing something obvious?

The Load methods work fine.

namespace SilverlightApplication2
{
    public class Customer
    {
        public string Name { get; set; }
    }

    public class RestHost
    {
        public event EventHandler Loaded = delegate { };
        public event EventHandler Error = delegate { };

        public Customer Customer { get; set; }
        public string ErrorMessage { get; set; }

        public RestHost()
        {
            Customer = new Customer();

            Load();
        }

        private void Load()
        {
            // begin loading customer
            var request = (HttpWebRequest)WebRequest.Create(new Uri("http://localhost:41078/SilverlightApplication2.Web/Service.svc/"));
            request.BeginGetResponse(delegate(IAsyncResult result)
            {
                try
                {
                    var resp = request.EndGetResponse(result);

                    var doc = XDocument.Load(resp.GetResponseStream());

                    Customer.Name = doc.Element("SampleItem").Element("Value").Value;

                    Loaded(this, EventArgs.Empty);
                }
                catch (Exception ex)
                {
                    ErrorMessage = ex.GetBaseException().Message;
                    Error(this, EventArgs.Empty);
                }
            }, null);
        }

        public void Save()
        {
            var request = (HttpWebRequest)WebRequest.Create(new Uri("http://localhost:41078/SilverlightApplication2.Web/Service.svc/"));
            request.Method = "POST";
            request.ContentType = "application/xml";
            request.BeginGetRequestStream(delegate(IAsyncResult result)
            {
                var postDoc = new XDocument(
                    new XElement("SampleItem", new XAttribute(XNamespace.Xmlns + "i", "http://www.w3.org/2001/XMLSchema-instance"),
                        new XElement("Value", Customer.Name)
                    )
                );
                postDoc.Save(request.EndGetRequestStream(result));

                request.BeginGetResponse(delegate(IAsyncResult result2)
                {
                    try
                    {
                        var resp = request.EndGetResponse(result2); // NotSupportedExecption here

                        var doc = XDocument.Load(resp.GetResponseStream());

                        Customer.Name = doc.Element("SampleItem").Element("Value").Value;

                        Loaded(this, EventArgs.Empty);
                    }
                    catch (Exception ex)
                    {
                        ErrorMessage = ex.GetBaseException().Message;
                        Error(this, EventArgs.Empty);
                    }
                }, null);
            }, null);


        }
    }
}

Also here is the Page Code as well

<UserControl x:Class="SilverlightApplication2.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Width="400" Height="300">
    <Grid x:Name="LayoutRoot" Background="White">
        <StackPanel Width="100" HorizontalAlignment="Left" Margin="15">
            <TextBlock>Customer</TextBlock>
            <TextBox x:Name="CustomerName" />
            <TextBlock Foreground="LightGray" x:Name="LoadingLabel" Margin="5,-19,0,0">Loading ...</TextBlock>
            <Button Content="Save" Margin="0,5,0,0" Click="Button_Click" />
        </StackPanel>
    </Grid>
</UserControl>

Code-Behind

namespace SilverlightApplication2
{
    public partial class Page : UserControl
    {
        private RestHost _host;

        public Page()
        {
            InitializeComponent();

            _host = new RestHost();
            _host.Loaded += delegate
            {
                this.Dispatcher.BeginInvoke(delegate
                {
                    this.LoadingLabel.Visibility = Visibility.Collapsed;
                    this.CustomerName.Text = _host.Customer.Name;
                });
            };
            _host.Error += delegate
            {
                this.Dispatcher.BeginInvoke(delegate
                {
                    HtmlPage.Window.Alert(_host.ErrorMessage);
                });
            };
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            _host.Customer.Name = this.CustomerName.Text;
            _host.Save();
        }
    }
}

Answer 1

Here is a nice walk-through on this...

http://blog.donnfelker.com/post/How-To-REST-Services-in-WCF-35-Part-2-The-POST.aspx