Prob using Document Selector

I am trying to adapt the Custom Image Widget Sample to look for a
document in a Library .... but when I select the document in this case a style sheet
I get the following error in the log file.

I tried following docs.sitefinity.com/feather-document-selector ... though was lost about step 4



JSON

"priority": 1,
  "components": [ "sf-document-selector" ]




DesignerView.Simple.cshtml
------------------------------
@using Telerik.Sitefinity.Mvc;

@using Telerik.Sitefinity.Frontend.Mvc.Helpers;



<form>
    
<div class="form-group">
        
<label>Choose a document:</label>


        <sf-document-selector sf-model="properties.DocumentId.PropertyValue"
                              sf-provider="properties.DocumentProviderName.PropertyValue"
                              sf-deselectable  />

    </div>

</form>


Script
-----------
var designerModule = angular.module('designer');
angular.module('designer').requires.push('sfDocumentSelector', 'sfSelectors');


Error in the logs is:
-----------
Type : System.Runtime.Serialization.SerializationException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
Message : There was an error deserializing the object of type Telerik.Sitefinity.Modules.Pages.Web.Services.Model.WcfControlProperty[]. End element 'PropertyValue' from namespace '' expected. Found element 'item' from namespace ''.
Source : System.Runtime.Serialization
Help link : 
Data : System.Collections.ListDictionaryInternal
TargetSite : System.Object ReadObjectHandleExceptions(System.Runtime.Serialization.XmlReaderDelegator, Boolean, System.Runtime.Serialization.DataContractResolver)
HResult : -2146233076
Stack Trace :    at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
   at System.Runtime.Serialization.Json.DataContractJsonSerializer.ReadObject(XmlDictionaryReader reader, Boolean verifyObjectName)
   at System.ServiceModel.Dispatcher.SingleBodyParameterDataContractMessageFormatter.ReadObject(Message message)
   at System.ServiceModel.Dispatcher.SingleBodyParameterMessageFormatter.DeserializeRequest(Message message, Object[] parameters)
   at System.ServiceModel.Dispatcher.DemultiplexingDispatchMessageFormatter.DeserializeRequest(Message message, Object[] parameters)
   at System.ServiceModel.Dispatcher.UriTemplateDispatchFormatter.DeserializeRequest(Message message, Object[] parameters)
   at System.ServiceModel.Dispatcher.DispatchOperationRuntime.DeserializeInputs(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)

Hi.

If you added this inside you widget designer

Be sure that you have this properties inside your widget controller:

public string DocumentProviderName get; set;

If you still confused, you can check source code of default feather document widget here: https://github.com/Sitefinity/feather-widgets/tree/master/Telerik.Sitefinity.Frontend.Media