Passing interface based property to Web API

Question

 public interface ISurvey
{
    List<ISurveyItem> Items { get; set; }
    int QueueId { get; set; }
    SurveyType Type { get; set; } //an enum

    SurveyResult ToSurveyResult();
    void CopyToSurveyDto(Survey dbsurvey);
}

public interface ISurveyItemBase
{
    int Sequence { get; set; }
    string Template { get; set; }
    string Label { get; set; }
    int Id { get; set; }
}

public interface ISurveyItem:ISurveyItemBase
{
    SurveyItemType Type { get; set; }//an enum
    string Value { get; set; }
}

public class Survey : ISurvey
{
    public List<ISurveyItem> Items { get; set; }
    public int QueueId { get; set; }
    public SurveyType Type { get; set; }

    public SurveyResult ToSurveyResult()
    {
       //implimentation
    }

    public void CopyToSurveyDto(Data.Survey dbsurvey)
    {
        //implimentation
    }
}

When I try pass the Survey object via POST to my Web API service, the Items property is serialized to an empty list. I imagine this has to do with it not knowing what concrete type to serialize the items too. Are there any pointers on how to do this?

One possible answer [here](http://stackoverflow.com/questions/15880574/json-net-how-to-deserialize-collection-of-interface-instances). — D Stanley, Apr 01 '14 at 20:18
Added ISurveyItem interface for you. That link does look like the path to an answer, I just don't know how to implement that on my Web API method. — Mike_G, Apr 01 '14 at 20:35

score 0 · Accepted Answer · answered Apr 02 '14 at 14:01

In order to accomplish this, I had to refactor a little bit:

public interface ISurvey<T>
    where T: ISurveyItem 
{
    List<T> Items { get; set; }
    int QueueId { get; set; }
    SurveyType Type { get; set; }
}

public class Survey : ISurvey<SurveyItem>
{
    public List<SurveyItem> Items { get; set; }
    public int QueueId { get; set; }
    public SurveyType Type { get; set; }
}

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Passing interface based property to Web API

1 Answers1