How to properly use javascript deserialization to convert a json string to a complex object?

Question

I have the following json object that is available in my .ashx handler (var items=):

{"Coverages":{"PersonID":10,"DetCode":"","Reimbursement":"","Deductible":"","MaximumPerAnnum":"","MaximumPerVisit":"","MaximumPerVisits":"","SvcCode":""},"CoverageCombinedMaximums":{"PersonID":10,"DetCode":["AAAAA","BBBBB","CCCCC"],"MaximumPerAnnum":""}} 

public void ProcessRequest (HttpContext context) {
        bool isSuccessful = true;

        var items = context.Request.Params["items"];
        if (isSuccessful)
        {

            JavaScriptSerializer ser = new JavaScriptSerializer();
            AdditionalCoveragesPackage package = ser.Deserialize<AdditionalCoveragesPackage>(items);


        }
        else
        {
            SendErrorMessage(context);
            return;
        } 
    }

Here is the structure of the class I'm trying to deserialize:

public class AdditionalCoverage
{
    public int PersonID { get; set; }
    public string DetCode { get; set; }
    public decimal? Reimbursement { get; set; }
    public decimal? Deductible { get; set; }
    public decimal? MaximumPerAnnum { get; set; }
    public decimal? MaximumPerVisit { get; set; }
    public int? MaximumPerVisits { get; set; }
    public string SvcCode { get; set; }

    public AdditionalCoverage()
    {
    }
}

public class AdditionalCoverageCombinedMaximum
{
    public int PersonID { get; set; }
    public string SvcCode { get; set; }
    public decimal? MaximumPerAnnum { get; set; }
    public List<string> DetCode { get; set; }

    public AdditionalCoverageCombinedMaximum()
    {
    }
}

public class AdditionalCoveragesPackage
{
    public List<AdditionalCoverage> Coverages { get; set; }
    public List<AdditionalCoverageCombinedMaximum> CoverageCombinedMaximums { get; set; }

    public AdditionalCoveragesPackage()
    {
    }

    public AdditionalCoveragesPackage(AdditionalCoverage coverage, AdditionalCoverageCombinedMaximum maximum)
    {
        List<AdditionalCoverage> coverages = new List<AdditionalCoverage>();
        coverages.Add(coverage);
        Coverages = coverages;

        List<AdditionalCoverageCombinedMaximum> maximums = new List<AdditionalCoverageCombinedMaximum>();
        maximums.Add(maximum);
        CoverageCombinedMaximums = maximums;
    }

    public AdditionalCoveragesPackage(List<AdditionalCoverage> coverages, List<AdditionalCoverageCombinedMaximum> maximums)
    {
        Coverages = coverages;
        CoverageCombinedMaximums = maximums;
    }
}

Edit: Here are my client side methods that need correction:

function saveCoverageDetails() {
                var handler = "HttpHandlers/UpdateAdditionalCoverageDetailsHandler.ashx";
                var coverages = { PersonID: personId, DetCode: "", Reimbursement: "", Deductible: "", MaximumPerAnnum: "", MaximumPerVisit: "", MaximumPerVisits: "", SvcCode: "" };
                var maximums = { PersonID: personId, DetCode: ["ACUPUN", "PODIAT", "OSTEOP"], MaximumPerAnnum: "" };
                var obj = { Coverages: coverages, CoverageCombinedMaximums: maximums };


                var data = ({ items: JSON.stringify(obj) });
                callHandler(handler, data, saveSuccessful, failure);

            }
   function callHandler(handler, obj, onSuccess, onFail) {

                $.ajax({
                    type: "POST",
                    url: handler,
                    data: obj,
                    dataType: "json",
                    success: onSuccess,
                    fail: onFail

                });

            }

When I'm using the javascript serializer it does return my AdditionalCoveragesPackage object - however - both of the properties: Coverages and CombinedMaximums are empty. How to get this to properly deserialize my json string?

Answer 1

In your JSON string Coverages and CoverageCombinedMaximums are simple objects, not arrays, so:

public class AdditionalCoveragesPackage
{
    public AdditionalCoverage Coverages { get; set; }
    public AdditionalCoverageCombinedMaximum CoverageCombinedMaximums { get; set; }
}

Also in your example JSON:

"MaximumPerAnnum":""

so make sure you define the corresponding property as a nullable decimal:

public decimal? MaximumPerAnnum { get; set; }

or the deserializer will blow.

Answer 2

The Coverages and CombinedMaximums properties in your JSON are objects, not arrays.
You should change those to arrays or change your C# class to not use List<T>s.

Answer 3

SLAKS and Darin Dimitrov both helped a ton. Ends up it works if I compose my JSON string as below (I had the array structured incorrectly and was passing empty strings instead of zeros for my numeric types). Here's the corrected client code:

 var handler = "HttpHandlers/UpdateAdditionalCoverageDetailsHandler.ashx";
                var coverages = [{ PersonID: personId, DetCode: "", Reimbursement: 0, Deductible: 0, MaximumPerAnnum: 0, MaximumPerVisit: 0, MaximumPerVisits: 0, SvcCode: "" }, { PersonID: personId, DetCode: "CHIROP", Reimbursement: 0, Deductible: 0, MaximumPerAnnum: 0, MaximumPerVisit: 0, MaximumPerVisits: 0, SvcCode: ""}];
                var maximums = [{ PersonID: personId, DetCode: ["ACUPUN", "PODIAT", "OSTEOP"], MaximumPerAnnum: 0 }, { PersonID: personId, DetCode: ["ACUPUN", "PODIAT", "OSTEOP"], MaximumPerAnnum: 0}];
                var obj = { Coverages: coverages, CoverageCombinedMaximums: maximums };

                var data = ({ items: JSON.stringify(obj) });
                callHandler(handler, data, saveSuccessful, failure);