Web Api with OData v4 throwing exception on $select

Question

I\'m using the latest version of WebApi and OData and everything is set up to work right. The only problem is when I try to use $select .

It throws the error bellow

Answer 1

Found a solution. It isn't perfect but it does work!

Maybe it will be useful for someone because I've spent on it few hours of research and trying.

Step #1 create custom xml formatter:

public class CustomXmlFormatter : MediaTypeFormatter
{
    private JsonMediaTypeFormatter jFormatter = null;
    public CustomXmlFormatter(JsonMediaTypeFormatter jFormatter)
    {
        SupportedMediaTypes.Add(new System.Net.Http.Headers.MediaTypeHeaderValue("application/xml"));
        this.jFormatter = jFormatter;
    }

    public override bool CanReadType(Type type)
    {
        return false;
    }

    public override bool CanWriteType(Type type)
    {
        return true;
    }
    public override Task WriteToStreamAsync(Type type, object value, System.IO.Stream writeStream, System.Net.Http.HttpContent content, System.Net.TransportContext transportContext)
    {
        return Task.Factory.StartNew(() =>
        {
            using (MemoryStream ms = new MemoryStream())
            {
                var tsk = jFormatter.WriteToStreamAsync(type, value, ms, content, transportContext);
                tsk.Wait();
                ms.Flush();
                ms.Seek(0, SeekOrigin.Begin);

                var xDoc = XDocument.Load(JsonReaderWriterFactory.CreateJsonReader(ms, new XmlDictionaryReaderQuotas()));

                using (XmlWriter xw = XmlWriter.Create(writeStream))
                {
                    xDoc.WriteTo(xw);
                }

            }
        });
    }
}

Step #2 register it in startup section:

        var formatters = ODataMediaTypeFormatters.Create();
        var jsonFormatter = config.Formatters.JsonFormatter;
        var customXmlFormatter = new CustomXmlFormatter(jsonFormatter);

        customXmlFormatter.AddQueryStringMapping("$format", "cxml", "application/xml");
        config.Formatters.Add(customXmlFormatter);

use it as http://url..../actionName?$format=cxml&$select=ObjectName,ObjectId