CODEWITHSUNDEEP
c#ajaxjsonasp.net-web-api
will
will

Reputation: 1012

Complex type is getting null in a ApiController parameter

I don´t know why my parameter "ParametroFiltro Filtro" is getting null, the other parameters "page" and "pageSize" is getting OK.

public class ParametroFiltro
{
    public string Codigo { get; set; }
    public string Descricao { get; set; }
}

My ApiController Get method:

public PagedDataModel<ParametroDTO> Get(ParametroFiltro Filtro, int page, int pageSize)

My ajax call:

var fullUrl = "/api/" + self.Api;
$.ajax({
    url: fullUrl,
    type: 'GET',
    dataType: 'json',
    data: { Filtro: { Codigo: '_1', Descricao: 'TESTE' }, page: 1, pageSize: 10 },
    success: function (result) {
        alert(result.Data.length);
        self.Parametros(result.Data);
    }
});

Upvotes: 54

Views: 52797

Answers (5)

Josh Noe
Josh Noe

Reputation: 2797

In .NET Core, the HttpClient sets the transfer-encoding: chunked header by default. This can cause the .NET Web API controller parameters to be null.

To get around this, you'll need to set the ContentLength header explicitly:

var json = JsonConvert.SerializeObject(myObject);
var content = new StringContent(json, Encoding.UTF8, "application/json");
content.Headers.ContentLength = json.Length;
var response = await client.PostAsync("http://my-api.com", content);

SO answer if you already know the transfer-encoding header is the issue: How to disable Chunked Transfer Encoding in ASP.Net C# using HttpClient

Related bug which won't be fixed, which gives some insight into the problem: https://github.com/dotnet/runtime/issues/30283

Upvotes: 0

graphicdivine
graphicdivine

Reputation: 11211

It's also possible to access POST variables via a Newtonsoft.Json.Linq JObject.

For example, this POST:

$.ajax({
    type: 'POST',
    url: 'URL',
    data: { 'Note': note, 'Story': story },
    dataType: 'text',
    success: function (data) { }
});

Can be accessed in an APIController like so:

public void Update([FromBody]JObject data)
{
    var Note = (String)data["Note"];
    var Story = (String)data["Story"];
}

Upvotes: 2

Bes Ley
Bes Ley

Reputation: 1797

If you append json data to query string, and parse it later in web api side. you can parse complex object too. It's useful rather than post json object, espeicaly in some special httpget requirement case. 

//javascript file 
    var data = { UserID: "10", UserName: "Long", AppInstanceID: "100", ProcessGUID: "BF1CC2EB-D9BD-45FD-BF87-939DD8FF9071" };
    var request = JSON.stringify(data);
    request = encodeURIComponent(request);

    doAjaxGet("/ProductWebApi/api/Workflow/StartProcess?data=", request, function (result) {
        window.console.log(result);
    });

    //webapi file:
    [HttpGet]
    public ResponseResult StartProcess()
    {
        dynamic queryJson = ParseHttpGetJson(Request.RequestUri.Query);
            int appInstanceID = int.Parse(queryJson.AppInstanceID.Value);
        Guid processGUID = Guid.Parse(queryJson.ProcessGUID.Value);
        int userID = int.Parse(queryJson.UserID.Value);
        string userName = queryJson.UserName.Value;
    }

    //utility function:
    public static dynamic ParseHttpGetJson(string query)
    {
        if (!string.IsNullOrEmpty(query))
        {
            try
            {
                var json = query.Substring(7, query.Length - 7); //seperate ?data= characters
                json = System.Web.HttpUtility.UrlDecode(json);
                dynamic queryJson = JsonConvert.DeserializeObject<dynamic>(json);

                return queryJson;
            }
            catch (System.Exception e)
            {
                throw new ApplicationException("can't deserialize object as wrong string content！", e);
            }
        }
        else
        {
            return null;
        }
    }

Upvotes: 1

Shyju
Shyju

Reputation: 218732

Provide the contentType property when you make the ajax call. Use JSON.stringify method to build the JSON data to post. change the type to POST and MVC Model binding will bind the posted data to your class object.

var filter = { "Filtro": { "Codigo": "_1", "Descricao": "TESTE" }, 
                                               "page": "1", "pageSize": "10" }; 
$.ajax({
    url: fullUrl,
    type: 'POST',
    dataType: 'json',
    contentType: 'application/json',
    data: JSON.stringify(filter),
    success: function (result) {
        alert(result.Data.length);
        self.Parametros(result.Data);
    }
});

Upvotes: 7

tpeczek
tpeczek

Reputation: 24125

You are trying to send a complex object with GET method. The reason this is failing is that GET method can't have a body and all the values are being encoded into the URL. You can make this work by using [FromUri], but first you need to change your client side code:

$.ajax({
    url: fullUrl,
    type: 'GET',
    dataType: 'json',
    data: { Codigo: '_1', Descricao: 'TESTE', page: 1, pageSize: 10 },
    success: function (result) {
        alert(result.Data.length);
        self.Parametros(result.Data);
    }
});

This way [FromUri] will be able to pick up your complex object properties directly from the URL if you change your action method like this:

public PagedDataModel<ParametroDTO> Get([FromUri]ParametroFiltro Filtro, int page, int pageSize)

Your previous approach would rather work with POST method which can have a body (but you would still need to use JSON.stringify() to format body as JSON).

Upvotes: 85

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