Send (Pass) JSON to API URL with POST Method in ASP.Net

Hi Amitabha,

For passing the json you need to create a class object and set the value and Serialize to json string and pass to the url.

For more details refer below sample code.

Model

public class JsonModel
{
    public string loginId { get; set; }
    public List<CardList> cardList { get; set; }
}

public class CardList
{
    public Int32 caNo { get; set; }
    public decimal dLimit { get; set; }
    public decimal adhoc { get; set; }
    public decimal mLimit { get; set; }
    public string limitType { get; set; }
}

Controller

public class CardAPIController : ApiController
{
    [Route("api/CardAPI/GetCards")]
    [HttpPost]
    public JsonModel GetCards(JsonModel model)
    {
        return model;
    }
}

Calling the API in Page

Namespaces

using System.Net;
using System.Text;
using System.Web.Script.Serialization;

Code

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        string apiUrl = "http://localhost:26404/api/CardAPI";

        JsonInput input = new JsonInput();
        input.loginId = "CK20004098";
        List<CardList> cardList = new List<CardList>();
        // Set the value from controls.
        cardList.Add(new CardList
        {
            caNo = 0054723860,
            dLimit = 10.00M,
            adhoc = 0.00M,
            mLimit = 0.00M,
            limitType = "1"
        });
        input.cardList = cardList;

        string inputJson = (new JavaScriptSerializer()).Serialize(input);
        WebClient client = new WebClient();
        client.Headers["Content-type"] = "application/json";
        client.Encoding = Encoding.UTF8;
        string json = client.UploadString(apiUrl + "/GetCards", inputJson);
        ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('" + json + "')", true);
    }
}

public class JsonInput
{
    public string loginId { get; set; }
    public List<CardList> cardList { get; set; }
}

public class CardList
{
    public Int32 caNo { get; set; }
    public decimal dLimit { get; set; }
    public decimal adhoc { get; set; }
    public decimal mLimit { get; set; }
    public string limitType { get; set; }
}

Screenshot