MVC3 - posting byte array to a controller - Databa

问题:

I am working on an MVC3 application. My client side ViewModel contains a SQL Server RowVersion property, which is a byte[]. It is rendered as an Object array on the client side. When I attempt to post my view model to a controller, the RowVersion property is always null.

I am assuming that the Controller serializer (JsonValueProviderFactory) is ignoring the Object array property.

I have seen this blog, however this does not apply, as I am posting JSON and not the form markup: http://thedatafarm.com/blog/data-access/round-tripping-a-timestamp-field-with-ef4-1-code-first-and-mvc-3/

My view renders my viewmodel like so:

<script type="text/javascript">
  var viewModel = @Html.Raw( Json.Encode( this.Model ) );
</script>

I then post the viewModel to the controller like so:

    var data = {
        'contact': viewModel
    };

    $.ajax({
        type: 'POST',
        url: '/Contact/Save',
        contentType: "application/json; charset=utf-8",
        data: JSON.stringify(data),
        dataType: 'json',
        success: function (data) {
            // Success
        },
        error: function (XMLHttpRequest, textStatus, errorThrown) {
            alert(XMLHttpRequest.responseText);
        }
    });

Here is my action in the controller:

  [HttpPost]
  public JsonResult Save(Contact contact) {
     return this.Json( this._contactService.Save( contact ) );
  }

UPDATE: based on Darin's answer.

I was hoping for a cleaner solution, but since Darin provided the only answer, I will have to add a custom property that will serialize my byte[] "row_version" property to a Base64 string. And when the Base64 string is set to the new custom property, it converts the string back to a byte[]. Below is the custom "RowVersion" property that I added to my model:

  public byte[] row_version {
     get;
     set;
  }

  public string RowVersion {
     get {

        if( this.row_version != null )
           return Convert.ToBase64String( this.row_version );

        return string.Empty;
     }
     set {

        if( string.IsNullOrEmpty( value ) )
           this.row_version = null;
        else
           this.row_version = Convert.FromBase64String( value );
     }
  }

回答1:

My client side ViewModel contains a SQL Server RowVersion property, which is a byte[]

Make it so that instead of a byte[] your view model contains a string property which is the base64 representation of this byte[]. Then you won't have any problems roundtripping it to the client and back to the server where you will be able to get the original byte[] from the Base64 string.

回答2:

Json.NET automatically encodes byte arrays as Base64.

You can use JsonNetResult instead of JsonResult:

from https://gist.github.com/DavidDeSloovere/5689824:

using System;
using System.Web;
using System.Web.Mvc;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;

public class JsonNetResult : JsonResult
{
    public override void ExecuteResult(ControllerContext context)
    {
        if (context == null)
        {
            throw new ArgumentNullException("context");
        }

        var response = context.HttpContext.Response;

        response.ContentType = !string.IsNullOrEmpty(this.ContentType) ? this.ContentType : "application/json";

        if (this.ContentEncoding != null)
        {
            response.ContentEncoding = this.ContentEncoding;
        }

        if (this.Data == null)
        {
            return;
        }

        var jsonSerializerSettings = new JsonSerializerSettings();
        jsonSerializerSettings.DateFormatHandling = DateFormatHandling.IsoDateFormat;
        jsonSerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
        var formatting = HttpContext.Current != null && HttpContext.Current.IsDebuggingEnabled ? Formatting.Indented : Formatting.None;
        var serializedObject = JsonConvert.SerializeObject(Data, formatting, jsonSerializerSettings);
        response.Write(serializedObject);
    }
}

Usage:

[HttpPost]
public JsonResult Save(Contact contact) {
    return new JsonNetResult { Data = _contactService.Save(contact) };
}