Question

I am trying to post some data to my MVC 3 controller through a hidden text field that contains some JSON. I have that JSON passed in via string coursesList. Anyone have an idea why this is not working?

All I’m doing is making a byte [] out of the JSON string, writing it to a MemoryStream, and deserializing that stream — or, attempting to. BookCourse bc always ends up with null properties.

Here’s something like the JSON I would be using:

[{"coursesection":"1234","netlogon":"jsmith","label":"CRSE-1313 Generic Course Titling ~ Joe Smith"}]

And here’s the object to be deserialized into:

using System.Runtime.Serialization;

namespace xxxx.Models
{
    [DataContract]
    public class BookCourse
    {
        [DataMember]
        public string coursesection { get; set; }

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

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

Finally, the controller action code to do it —

var byteArray = Encoding.ASCII.GetBytes(coursesList);

// Deserialize byte array to data type
var stream = new MemoryStream();
stream.Write(byteArray, 0, byteArray.Length);
var crs = new DataContractJsonSerializer(typeof(BookCourse));
stream.Position = 0;

// Read stream to object
ad.CourseSectionIDs = new List<int>();
try
{
    var bc = (BookCourse) crs.ReadObject(stream);
    while (bc.coursesection != null)
    {
        cs.AssociateCourseBook(bc.netlogon, bc.coursesection, ad.ISBN);
        bc = (BookCourse)crs.ReadObject(stream);
    }
}
catch (System.Runtime.Serialization.SerializationException e)
{
    // Is this best practice for handling "none"?
}

Answer 1

Your JSON string represents a collection of BookCourse, not a single BookCourse. So adapt your code:

var serializer = new DataContractJsonSerializer(typeof(BookCourse[]));

and then:

var bookCourses = (BookCourse[])crs.ReadObject(stream);

or if you want to work with a single BookCourse you will need to change your JSON string and remove the wrapping square brackets which represent a collection.