System.InvalidOperationException: There was an error reflecting type 'PdfSharp.Pdf.PdfDocument'. ---> System.InvalidOperationException: Cannot serialize member 'PdfSharp.Pdf.PdfObject.Reference' of type 'PdfSharp.Pdf.Advanced.PdfReference', see inner exception for more details. ---> System.InvalidOperationException: PdfSharp.Pdf.Advanced.PdfReference cannot be serialized because it does not have a parameterless constructor.
   --- End of inner exception stack trace ---
   at System.Xml.Serialization.StructModel.CheckSupportedMember(TypeDesc typeDesc, MemberInfo member, Type type)
   at System.Xml.Serialization.StructModel.GetPropertyModel(PropertyInfo propertyInfo)
   at System.Xml.Serialization.StructModel.GetFieldModel(MemberInfo memberInfo)
   at System.Xml.Serialization.XmlReflectionImporter.InitializeStructMembers(StructMapping mapping, StructModel model, Boolean openModel, String typeName, RecursionLimiter limiter)
   at System.Xml.Serialization.XmlReflectionImporter.ImportStructLikeMapping(StructModel model, String ns, Boolean openModel, XmlAttributes a, RecursionLimiter limiter)
   at System.Xml.Serialization.XmlReflectionImporter.InitializeStructMembers(StructMapping mapping, StructModel model, Boolean openModel, String typeName, RecursionLimiter limiter)
   at System.Xml.Serialization.XmlReflectionImporter.ImportStructLikeMapping(StructModel model, String ns, Boolean openModel, XmlAttributes a, RecursionLimiter limiter)
   at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel model, String ns, ImportContext context, String dataType, XmlAttributes a, Boolean repeats, Boolean openModel, RecursionLimiter limiter)
   --- End of inner exception stack trace ---
   at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel model, String ns, ImportContext context, String dataType, XmlAttributes a, Boolean repeats, Boolean openModel, RecursionLimiter limiter)
   at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(TypeModel model, String ns, ImportContext context, String dataType, XmlAttributes a, RecursionLimiter limiter)
   at System.Xml.Serialization.XmlReflectionImporter.ImportElement(TypeModel model, XmlRootAttribute root, String defaultNamespace, RecursionLimiter limiter)
   at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(Type type, XmlRootAttribute root, String defaultNamespace)
   at System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(Type type, XmlRootAttribute root)
   at System.Web.Services.Protocols.XmlReturn.GetInitializers(LogicalMethodInfo[] methodInfos)
   at System.Web.Services.Protocols.XmlReturnWriter.GetInitializers(LogicalMethodInfo[] methodInfos)
   at System.Web.Services.Protocols.MimeFormatter.GetInitializers(Type type, LogicalMethodInfo[] methodInfos)
   at System.Web.Services.Protocols.HttpServerType..ctor(Type type)
   at System.Web.Services.Protocols.HttpServerProtocol.Initialize()
   at System.Web.Services.Protocols.ServerProtocol.SetContext(Type type, HttpContext context, HttpRequest request, HttpResponse response)
   at System.Web.Services.Protocols.ServerProtocolFactory.Create(Type type, HttpContext context, HttpRequest request, HttpResponse response, Boolean& abortProcessing)

using PdfSharp.Pdf;
using PdfSharp.Pdf.Advanced;
using PdfSharp.Drawing;

        MemoryStream stream = new MemoryStream();
        PdfDocument document = new PdfDocument();
        XImage image = XImage.FromGdiPlusImage(data);
        PdfPage imagePage = new PdfPage();
        imagePage.Height = image.PointHeight;
        imagePage.Width = image.PointWidth;
        document.Pages.Add(imagePage);
        int pageCount = 1;
        XGraphics graphics = XGraphics.FromPdfPage(document.Pages[pageCount]);
        graphics.DrawImage(image, 0, 0);
        document.Save(stream);

        Context.Response.Buffer = true;
        Context.Response.Clear();
        Context.Response.ContentType = "application/pdf";
        Context.Response.AddHeader("content-disposition", "attachment; filename=" + name);
        Context.Response.BinaryWrite(stream.ToArray());
        stream.Close();
        Context.Response.Flush();
        Context.Response.End();