WebApi can't deserialize XML into a list

Question

I'm trying to POST a list or array of values that are automatically deserialized to a complex object called RejectModel. This works perfectly when receiving the data as JSON, but when sending XML data, the automatic serializer makes rejectionList NULL.

I have tried using the default Xml serializer instead of the dataContract serializer. This gives me the following error:

No MediaTypeFormatter is available to read an object of type 'List'1' from content with media type 'application/xml'.

I have tried changing the list to an Array with the same results.

I feel like I'm just not naming my XML containing element correctly. Any suggestions would be appreciated.

---

Post declaration. Accept a list of rejectModels.

public HttpResponseMessage Post(List<RejectModel> rejectionList)
        {
            if (rejectionList == null)
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, "The request was empty, malformed, or did not include an array of values.");
            }
            else if (rejectionList.Rejections.Length == 0)
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, "An empty array was passed.");
            }
        }

Reject Model, I want to accept a list/array of these

[DataContract]
public class RejectModel : BaseModel
{
    [Required]
    [DataMember(IsRequired = true)]
    public int LeadId { get; set; }

    [DataMember]
    public int? PropertyId { get; set; }

    [DataMember]
    public string PartnerPropertyId { get; set; }

    [DataMember]
    public string OriginalSource { get; set; }

    [DataMember]
    public DateTime OriginalReferralDate { get; set; }
}

One of my many request attempts. I have tried many tag names for "rejectList". I include "Accept: application/xml" in the request header.

<?xml version="1.0" encoding="UTF-8"?>
<rejectList>
 <RejectModel>
<LeadId>10102085</LeadId>
<PropertyId>60278</PropertyId>
 </RejectModel>
</rejectList>

Answer 1

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When using DataContractSerializer (the default xml serializer for WebAPI), you must include a namespace in your XML request and on the object's DataContract. You also need to name the xml collection "ArrayOf..." even if you're taking in a List. Here's an example following the structure of my original question:

[DataContract(Namespace = "http://blahblah.org/2013/Some.Namespace.You.Defined")]
public class RejectList{
    List<RejectModel> list{
        get;
        set;
    }
}

<ArrayOfRejectModel xmlns="http://blahblah.org/2013/Some.Namespace.You.Defined">
  <RejectModel> ... </RejectModel>
  <RejectModel> ... </RejectModel>
</ArrayOfRejectModel>

However, if you include a blank namespace with your DataContract decoration, you don't have to include a namespace inside the XML request.

[DataContract(Namespace = "")]
public class RejectList{
    List<RejectModel> list{
        get;
        set;
    }
}

<ArrayOfRejectModel>
  <RejectModel> ... </RejectModel>
  <RejectModel> ... </RejectModel>
</ArrayOfRejectModel>

Related reading:

Adjust MVC 4 WebApi XmlSerializer to lose the nameSpace

Remove namespace in XML from ASP.NET Web API

How to serialize xml into desired format in asp.net web api