Passing a JavaScript Object to an ASP.NET Handler

Question

Passing a JavaScript Object to an ASP.NET Handler

How can I send a JavaScript object to an ASP.NET Handler and extract its values?

I have defined a complex type object as follows:

function AccountObjCreate() {
var AccountsView = {};
AccountsView.Username = null;
AccountsView.Email = null;
AccountsView.Password = null;

return AccountsView;
}

I populate this object like so:

var aView = AccountObjCreate();
aView.Username = $('#tbUserName').val().trim();
aView.Email = $('#tbEmail').val().trim().toLowerCase();
aView.Password = $('#tbPassword').val().trim();

Then I make the following call:

$.post("/Handlers/AccountHandler.ashx", { obj: aView },
        function (results) {
            if (results.isSuccess) {
                alert(results.msg);
            } else {
                alert(results.msg);
            }
        }, "json");

Upon inspecting the console, I can see all my data within aView displayed as JSON.

The code in my ASP.NET Handler page is:

context.Response.ContentType = "application/json";
context.Response.ContentEncoding = Encoding.UTF8;
string obj = context.Request["obj"];

However, the obj variable turns out to be NULL.

c#javascript asp.net json httphandler

Answer 1

Answer №1

To successfully transmit the object to the server, it must first be serialized into a string. This can be achieved by following a specific method as outlined here, or by utilizing the JSON library for Javascript available here. The next step involves deserializing the object using the .NET JavaScriptSerializer class.

Here is an example of JavaScript code:

var data = {
    obj: JSON.stringify(aView)
};
$.post("/Handlers/AccountHandler.ashx", data, function(results) {
    if (results.isSuccess) {
        alert(results.msg);
    } else {
        alert(results.msg);
    }
}, "json");

Upon receiving the request on the server handler, the JSON string can then be parsed using the aforementioned JavaScriptSerializer class.

public class AccountsView {
    public string Username;
    public string Email;
    public string Password;
}

public void ProcessRequest(HttpContext context)
{
    JavaScriptSerializer serializer = new JavaScriptSerializer();
    string value = context.Request["obj"];
    var aView = serializer.Deserialize(value, typeof(AccountsView));

    context.Response.ContentType = "application/json";
    context.Response.ContentEncoding = Encoding.UTF8;
}

Answer 2

To successfully transmit the object to the server, it must first be serialized into a string. This can be achieved by following a specific method as outlined here, or by utilizing the JSON library for Javascript available here. The next step involves deserializing the object using the .NET JavaScriptSerializer class.

Here is an example of JavaScript code:

var data = {
    obj: JSON.stringify(aView)
};
$.post("/Handlers/AccountHandler.ashx", data, function(results) {
    if (results.isSuccess) {
        alert(results.msg);
    } else {
        alert(results.msg);
    }
}, "json");

Upon receiving the request on the server handler, the JSON string can then be parsed using the aforementioned JavaScriptSerializer class.

public class AccountsView {
    public string Username;
    public string Email;
    public string Password;
}

public void ProcessRequest(HttpContext context)
{
    JavaScriptSerializer serializer = new JavaScriptSerializer();
    string value = context.Request["obj"];
    var aView = serializer.Deserialize(value, typeof(AccountsView));

    context.Response.ContentType = "application/json";
    context.Response.ContentEncoding = Encoding.UTF8;
}

Answer 3

Answer №2

If you're using jQuery, keep in mind that it doesn't automatically convert objects to strings for you - you'll have to handle that yourself.

To simplify the process, you can download a library such as https://github.com/douglascrockford/JSON-js

Simply add the script reference to your HTML file and update your $.post function like this:

$.post("/Handlers/AccountHandler.ashx", { obj: JSON.stringify(aView, null, 2) }...

It's important to note that the ContentType should remain default, even when sending JSON data. The content type will be standard post data.

obj={"Username":"MyUsername", "Password":"MyPassword"...

When submitting actual JSON data, it would look something like this:

{"obj":{"Username":"MyUsername", "Password":"MyPassword"...

To simplify this process further, consider looking into ASP.Net MVC. The Controller Methods can automatically deserialize JSON objects into .Net models, allowing for simpler client-side code:

$.post("/Handlers/AccountHandler.ashx", JSON.stringify({ view: aView }, null, 2) }...

Create a .Net class that matches the structure of 'aView':

class Account { 
    public string Username { get; set; } 
    public string Password { get; set; }
    public string Email { get; set; }
}

Then define a controller method like so:

public JsonResult SaveAccount(Account view)

This approach simplifies the process significantly. :)

Answer 4

If you're using jQuery, keep in mind that it doesn't automatically convert objects to strings for you - you'll have to handle that yourself.

To simplify the process, you can download a library such as https://github.com/douglascrockford/JSON-js

Simply add the script reference to your HTML file and update your $.post function like this:

$.post("/Handlers/AccountHandler.ashx", { obj: JSON.stringify(aView, null, 2) }...

It's important to note that the ContentType should remain default, even when sending JSON data. The content type will be standard post data.

obj={"Username":"MyUsername", "Password":"MyPassword"...

When submitting actual JSON data, it would look something like this:

{"obj":{"Username":"MyUsername", "Password":"MyPassword"...

To simplify this process further, consider looking into ASP.Net MVC. The Controller Methods can automatically deserialize JSON objects into .Net models, allowing for simpler client-side code:

$.post("/Handlers/AccountHandler.ashx", JSON.stringify({ view: aView }, null, 2) }...

Create a .Net class that matches the structure of 'aView':

class Account { 
    public string Username { get; set; } 
    public string Password { get; set; }
    public string Email { get; set; }
}

Then define a controller method like so:

public JsonResult SaveAccount(Account view)

This approach simplifies the process significantly. :)

Passing a JavaScript Object to an ASP.NET Handler

Answer №1

Answer №2

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