Question

I am implementing, for the first time, Json.NET for my ASP.NET MVC2 site.

My original code looked like this:

[HttpPost]
public ActionResult FindMe(string searchFirstName, string searchLastName)
{
    this.searchFirstName = searchFirstName;
    this.searchLastName = searchLastName;
    IEnumerable<HomePageUser> results = doSearch();
    bool success = (results.Count() == 0) ? false : true;

    return Json(new
    {
        success = success,
        results = results
    });
}

The results were problematic due to the fact that one of the items in the results set is an Enum and I really want the Text value, not the numeric one. Additionally, the date format is a problem.

So, I then found Json.NET and changed my code to this:

[HttpPost]
public JsonNetResult FindMe(string searchFirstName, string searchLastName)
{
    this.searchFirstName = searchFirstName;
    this.searchLastName = searchLastName;
    IEnumerable<HomePageUser> results = doSearch();
    bool success = (results.Count() == 0) ? false : true;

    JsonNetResult jsonNetResult = new JsonNetResult();
    jsonNetResult.SerializerSettings.Converters.Add(new IsoDateTimeConverter());
    jsonNetResult.Data = results;// how to add success true/false info?

    return jsonNetResult;
}

This fixes the above two issues, but now I’m wondering how to make this seamless with my existing javascript code that was expecting json that looked like:

{
    "success":true,
    "results":[{
        "UserId":545,
        "FirstName":"Scott",
        "LastName":"Roberson"}]
}

This allowed me to first test for response.success before proceeding to write out the answer, versus moving into the section to handle errors.

So, my question is how do I add a top-level success json node to live beside the results node?

Thanks.

UPDATE:

As is often the case, the act of writing out a question sparked an idea in one of those Doh! moments.

if I add:

var returnPackage = new { success = success, results = results};

then add this to the jsonNetResult.Data like so:

jsonNetResult.Data = returnPackage;

It works perfectly.

Thanks, anyway.

Final code:

[HttpPost]
public JsonNetResult FindMe(string searchFirstName, string searchLastName)
{
    this.searchFirstName = searchFirstName;
    this.searchLastName = searchLastName;
    IEnumerable<HomePageUser> results = doSearch();
    bool success = (results.Count() == 0) ? false : true;

    var returnPackage = new { success = success, results = results};

    JsonNetResult jsonNetResult = new JsonNetResult();
    jsonNetResult.SerializerSettings.Converters.Add(new IsoDateTimeConverter());
    jsonNetResult.Data = returnPackage;

    return jsonNetResult;
}

Answer 1

Here’s what I do in my MVC/Ajaxy apps. Define a new class:

public class JsonResultData
{
    private bool _success = true;
    public bool Success
    {
        get { return _success; }
        set { _success = value; }
    }

    public object Value { get; set; }
    public List<string> Errors { get; set; }

    public JsonResultData()
    {
        this.Errors = new List<string>();
    }
}

Then set your return data value to:

jsonNetResult.Data = new JsonResultData { Value = results };

JsonResultData.Success property is what you want to test in the json response first. It defaults to true, but if something goes wrong in your server-side method, you set it to false and add your error message, like this:

    catch (Exception ex)
    {
        List<string> errors = new List<string>();
        errors.Add(ex.ToString());
        jsonNetResult.Data = new JsonResultData { Success = false, Errors = errors };
    }