Question

我在MVVMCross的PCL项目中使用WCF Data Services 5.6。在WPF客户端中，以下代码（在viewModel中）的工作方式类似于魅力（基于http://msdn.microsoft.com/en-us/library/dd756367(v=vs.110).aspx处的示例）：

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);

但是在Android客户端中，“resultQuery.EndExecute（result）”会抛出以下异常：

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 }

有什么想法吗？有人用MonoDroid测试了WCF Data Services 5.6吗？

提前致谢

Answer 1

https://github.com/mono/mono/blob/master/mcs/class/System/System.Net/WebResponse.cs

您可以从源代码中看到它确实没有实现。

Mono的WCF支持尚未完成，因此将其用于WCF数据服务存在风险。

如果可能的话，在服务器端使用ASP.NET Web API而不是WCF，然后在客户端通过HttpClient获得更好的支持。

Answer 2

该错误发生在HttpWebResponse.cs中，它应该添加以下内容：

public override bool SupportsHeaders
{
    get
    {
        return true;
    }
}

Answer 3

应该使用最新版本：Mono for Android 4.12.3.I测试并发现它适用于Microsoft.Data.Service.Client.Portable.dll。

MVVMCross + Xamarin + WCF数据服务5.6 =未实现异常？

3 个答案: