MVC - Http Post JSON - Serialization Dependency

Question

I am using ASP MVC with JQuery and posting json data to my controller.

var jsonPostData = { 
     control: "PersonControl",
     data: {
            name: "Craig",
            age: 25
     } 
};

I am using the following to perform my serialization.

public override void OnActionExecuting(ActionExecutingContext FilterContext)
{
    var contentType = FilterContext.HttpContext.Request.ContentType
                   ?? string.Empty;
    if (contentType.Contains("application/json"))
    {
        object JsonObject = new DataContractJsonSerializer(RootType)
            .ReadObject(FilterContext.HttpContext.Request.InputStream);
        FilterContext.ActionParameters[Param] = JsonObject;
    }
}

Which serializes to the following model:

[DataContract]
public class ControlModel   
{
    [DataMember(Name = "control", IsRequired = true)]
    public string Control { get; set; }
    [DataMember(Name = "data"]
    public object Data { get; set; }
}

This is working fine.

The problem I am trying to resolve is that the type for data is dependent upon what is passed for the control value.

I use reflection to create a control instance from the control value. I would like to be able to then call into this control instance to get a dynamic type back to then use to serialize "Data" separately.

CustomControl.GetDataType() here would return typeof(PersonModel)

object JsonObject = new DataContractJsonSerializer(CustomControl.GetDataType())
    .ReadObject(FilterContext.HttpContext.Request.InputStream);



[DataContract] //this is what data could be serialized too
public class PersonModel   
{
    [DataMember(Name="name", IsRequired=true)]
    public string Name { get; set; }    
    [DataMember(Name="age", IsRequired=true)]
    public string Age { get; set; }
}

So essentially I am trying to find if I can parse my JSON in two different partial chunks.

Ideas? Suggestions?

As per the suggestion from thaBadDawg, I ended up going with the JSON.Net route, which allows me to parse the JSON items individually, allowing me to first pull out the control, and then later in my control implementation pull out the needed custom data items.

Here is my example above rewritten (and simplified for the example) to use this:

public override void OnActionExecuting(ActionExecutingContext FilterContext)
{
    if ((FilterContext.HttpContext.Request.ContentType ?? string.Empty).Contains("application/json"))
    {
        var bytes = new byte[FilterContext.HttpContext.Request.InputStream.Length];

        FilterContext.HttpContext.Request.InputStream.Read(bytes, 0, bytes.Length);
        FilterContext.HttpContext.Request.InputStream.Position = 0;

        JObject JsonObject = JObject.Parse(Encoding.UTF8.GetString(bytes));

        FilterContext.ActionParameters["Control"] = (string) JsonObject["control"];
        FilterContext.ActionParameters["Action"] = (string)JsonObject["action"];
    }
}

I'm not reaching the point of your question. Aren't you being able to deserialize the data? — Guilherme Duarte, Apr 29 '11 at 15:47
@gjsduarte - I am attempting to deserialize the json in two parts, first the control, then the data. This is because the type that I want data to be serialized to, is dependent upon what control is used. — cweston, Apr 29 '11 at 15:50
Is this what your looking for? http://stackoverflow.com/questions/560575/asp-net-mvc-how-to-pass-json-object-from-view-to-controller-as-parameter — Guilherme Duarte, Apr 29 '11 at 16:02
@gjsduarte - Thanks, but I am already making use of many of those suggestions — cweston, Apr 29 '11 at 16:53

score 1 · Accepted Answer · answered Apr 29 '11 at 16:07

Off the top of my head I would suggest going the Json.Net route using it as a Linq to JSON parser and skip the deserialization of the top level (just query it for it's value) and then have it decide what type to deserialize the nested object into. My experience with the DataContractJsonSerializer leads me to believe that you will be unable to find a simple solution going that route.

There's a pretty good example of using Linq to JSON here : http://james.newtonking.com/projects/json/help/LINQtoJSON.html

MVC - Http Post JSON - Serialization Dependency

1 Answers1