MVVMCross + Xamarin + WCF Data Services 5.6 = Not Implemented Exception? - xamarin.android

Question

I'm using WCF Data Services 5.6 in a PCL project with MVVMCross. In the WPF client the following code (in the viewModel) works like a charm (based on the sample found at http://msdn.microsoft.com/en-us/library/dd756367(v=vs.110).aspx):
DataServiceQuery<T> query = this.LoadItemsQuery;
query.BeginExecute((result) =>
{
try
{
DataServiceQuery<T> resultQuery = result.AsyncState as DataServiceQuery<T>;
foreach (T item in resultQuery.EndExecute(result))
{
// Do something here
}
}
catch (Exception ex)
{
PublishException(ex);
}
}
, query);
But in the Android client, "resultQuery.EndExecute(result)" throws the following exception:
System.InvalidOperationException: An error occurred while processing this request. ---> System.NotImplementedException: The requested feature is not implemented.
at System.Net.WebResponse.get_SupportsHeaders () [0x00000] in <filename unknown>:0
at System.Data.Services.Client.HttpWebRequestMessage.EndGetResponse (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0
at System.Data.Services.Client.ODataRequestMessageWrapper.EndGetResponse (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0
at System.Data.Services.Client.DataServiceContext.GetResponseHelper (System.Data.Services.Client.ODataRequestMessageWrapper request, IAsyncResult asyncResult, Boolean handleWebException) [0x00000] in <filename unknown>:0
at System.Data.Services.Client.DataServiceContext.EndGetResponse (System.Data.Services.Client.ODataRequestMessageWrapper request, IAsyncResult asyncResult) [0x00000] in <filename unknown>:0
at System.Data.Services.Client.RequestInfo.EndGetResponse (System.Data.Services.Client.ODataRequestMessageWrapper request, IAsyncResult asyncResult) [0x00000] in <filename unknown>:0
at System.Data.Services.Client.QueryResult.AsyncEndGetResponse (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0
--- End of inner exception stack trace ---
at System.Data.Services.Client.BaseAsyncResult.EndExecute[QueryResult] (System.Object source, System.String method, IAsyncResult asyncResult) [0x00000] in <filename unknown>:0
at System.Data.Services.Client.QueryResult.EndExecuteQuery[Appointment] (System.Object source, System.String method, IAsyncResult asyncResult) [0x00000] in <filename unknown>:0 }
Any ideas? Has someone tested WCF Data Services 5.6 with MonoDroid?
Thanks in advance

Answer 1

https://github.com/mono/mono/blob/master/mcs/class/System/System.Net/WebResponse.cs
You can see from the source code that it is indeed not implemented.
Mono's WCF support is not complete, so using it against WCF Data Services is risky.
If possible, use ASP.NET Web API instead of WCF at server side, and then on client side you get better support via HttpClient.

Answer 2

The bug is in HttpWebResponse.cs,which should add the following:
public override bool SupportsHeaders
{
get
{
return true;
}
}

Answer 3

Should work with the latest release : Mono for Android 4.12.3.I test and found it worked with Microsoft.Data.Service.Client.Portable.dll.