Question

I’m using JavaScriptSerializer and when I try to deserialize a JSON object as

Json.Deserialize<List<HeyWatchVideo>>(Request("video")); 

I get following Exception:

MissingMethodException: No parameterless constructor defined for type of ‘System.String’.

I tried matching my .NET classes, and the types of their properties just as close to my json object, but still getting above exception

My JSON object:

[{
    "url": "http://media.heywatch.com.s3.amazonaws.com/14/14/a0f356a48381092e6e2a34021ce86b19/11002247",
    "specs": {
        "size": 3808,
        "video": {
            "fps": 11.63,
            "height": 360,
            "length": 61,
            "width": 640,
            "aspect": 1.78,
            "codec": "mpeg4",
            "container": "mov",
            "rotation": 0,
            "bitrate": 507,
            "pix_format": "yuv420p",
            "stream": 0.1
        },
        "thumb": "http://media.heywatch.com.s3.amazonaws.com/14/14/ad59fa501d1b9e826552dfc010cf1c98/11002247.jpg",
        "audio": {
            "sample_rate": 11025,
            "channels": 1,
            "codec": "aac",
            "bitrate": 38,
            "synched": true,
            "stream": 0
        },
        "mime_type": "video/mp4"
    },
    "title": "elves.mp4",
    "filename": "11002247",
    "link": "http://heywatch.com/video/21091957.bin",
    "updated_at": "2013-01-14T15:44:53+01:00",
    "created_at": "2013-01-14T15:44:53+01:00",
    "id": 21091957
}]

My Classes

public class HeyWatchVideo
{
    public DateTime Created_At { get; set; }
    public string Title { get; set; }
    public Dictionary<string, string> Specs { get; set; }
    public DateTime Updated_At { get; set; }
    public int Id { get; set; }
    public string Filename { get; set; }
    public string Link { get; set; }
    public string Url { get; set; }
}

public class HeyWatchVideoSpecs
{
    public HeyWatchVideoSpecsAudio Audio { get; set; }
    public HeyWatchVideoSpecsVideo Video { get; set; }
    public string Thumb { get; set; }
    public string Mime_type { get; set; }
    public int Size { get; set; }
}

public class HeyWatchVideoSpecsVideo
{
    public int Rotation { get; set; }
    public double Aspect { get; set; }
    public string Container { get; set; }
    public string Codec { get; set; }
    public int Length { get; set; }
    public int Width { get; set; }
    public int Bitrate { get; set; }
    public string Pix_format { get; set; }
    public double Fps { get; set; }
    public double Stream { get; set; }
    public int Height { get; set; }
}

public class HeyWatchVideoSpecsAudio
{
    public int Channels { get; set; }
    public int Sample_rate { get; set; }
    public string Codec { get; set; }
    public bool Synched { get; set; }
    public int Bitrate { get; set; }
    public int Stream { get; set; }
}

What am I doing wrong here?

Answer 1

My problem was solved. My .Net Classes didn’t match exactly as Json object. (Both are in the question)

When they were matched, this error went away