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Jquery .post method is sending a null value. How to pass actual value to controller?

I have a controller that applies to an edit view in asp.net MVC. I have an actionlink that sends the row Id to the controller which then brings back the correct row to see in the associated view.
I then have a partial view below that. That also requires a parameter in order to bring associated data from another table.
I have a Jquery .post call that runs after the page is loaded. I can alert out and show the exact value I want to send to the controller.
$(document).ready(function () {
var url = "/Home/MmsAndNotes";
var Uc = $("#Id").serialize();
alert(Uc);
$.post(url, {Id: Uc}, function (data) {
alert("what is Uc now? " + uc); //just for testing
});
})
I have also used it this way.
$(document).ready(function () {
var url = "/Home/MmsAndNotes";
var Uc = $("#Id").val();
alert(Uc);
$.post(url, Uc, function (data) {
});
})
the alerts come up and show the value I want. However, when the .post call runs, it sends a null value. Here is my controller.
public ActionResult MmsAndNotes(string Id)
{
//Declare LogisticsVM for individual policy info
LogisticsMMS_NotesVM model;
if(uc == null)
{
return Content("uc is empty.");
}
int val = Convert.ToInt32(uc);
using (Db db = new Db())
{
LogisticsMMS_NotesDTO dto = db.LogisticsMMS.Find(val);
//confirm policy exists
if (dto == null)
{
return Content("This policy cannot be found." + val);
}
model = new LogisticsMMS_NotesVM(dto);
}
return PartialView(model);
}
It always returns as uc is empty. I repeat, when the alerts come up. I get the correct value to send to the controller. But once it sends, something happens and it converts to null. HELPPPPP.. please .. I'm losing my mind over this one.

I don't know why, but changing my $.post() call to an $.ajax({}) call solved the issue. As you can see above, I had the $.post call. Using this instead,
$.ajax({
type: "POST",
url: "/Home/MmsAndNotes",
dataType: 'text',
data: { Id: Uc }
});
Solved it. I thought Jquery's shortened calls worked the same way. They certainly might, but doing it this way was the only way it worked for me.
P.S. Thanks Tyler (above) for your comments.

this solution should be work :
$(document).ready(function () {
$.ajax({
url: '/Home/MmsAndNotes',
type: 'GET',
dataType: "html",
data: { uc : $("#Id").val() },
success: function (result) {
code here
}
});
})
You need to verify if $("#Id").val() is not empty

Server result to webpage

I am trying to simply write out some data to my webpage as a result of a callback. Everything works up until the point where I need to output the result of the callback.
Client-side:
function toServer(data) {
var dataPackage = data + "~";
jQuery('form').each(function () {
document.getElementById('payload').value = JSON.stringify({ sendData: dataPackage });
$.ajax({
type: "POST",
async: true,
url: window.location.href.toString(),
data: jQuery(this).serialize(),
success: function (result) {
//this does not work because it just puts an entire source code copy of my site in there instead...
//document.getElementById('searchResults').value = result
console.log("callback compelete");
},
error: function(error) {
console.log("callback Error");
}
});
});
}
Server-Side: (on page load)
//holds actions from page
string payload = HttpContext.Current.Request.Form["payload"] ?? String.Empty;
// See if there were hidden requests (callbacks)
if (!String.IsNullOrEmpty(payload))
{
string temp_AggregationId = CurrentMode.Aggregation;
string[] temp_AggregationList = temp_AggregationId.Split(' ');
Perform_Aggregation_Search(temp_AggregationList, true, Tracer);
}
else
{
HttpContext.Current.Session["SearchResultsJSON"] = "";
}
The rest of the server-side code works properly and just handles the parsing of the incoming and performs a search of the db and then parses the search results into a JSON obj.
Currently, the only way the json obj gets written to the page is if I call it without the callback (just call it on page load). Also, in firebug, it looks like the entire page source is posting back as the 'result' of the callback. I do see my json result within the posted back 'result' but it also contains the entire page HTML.
Moreover, I can't seem to get the result to post to the page which is the whole point. Actually, I could get the result to post to the page by simply uncommenting that bit in the client side code but it posts a copy of my site and not the actual result I thought I created...
What am I missing? How do you explicitly state in the C# code what is returned to the JS callback as 'result'?

You get the entire page because you're making a request to an ASP.NET page. In fact, you're requesting the vary same page you're viewing. The server is returning what it would return if you were submitting a form.
To get JSON data, you need to create a web method to handle your request. Read this article, it will help you. It shows you how to return simple text, but you can return JSON too. Information on this MSDN article.
Finally, to make sure jQuery is parsing the server response as JSON, change your request and indicate it explicitly:
function toServer(data) {
var dataPackage = data + "~";
jQuery('form').each(function () {
document.getElementById('payload').value = JSON.stringify({ sendData: dataPackage });
$.ajax({
type: "POST",
async: true,
url: window.location.href.toString(),
data: jQuery(this).serialize(),
dataType: 'json',
success: function (result) {
//this does not work because it just puts an entire source code copy of my site in there instead...
//document.getElementById('searchResults').value = result
console.log("callback compelete");
},
error: function(error) {
console.log("callback Error");
}
});
});
}

Passing an array from javascript to code behind - C#

In my website, i'm declaring an array in javascript and insert them elements dynamically. So now, I want use that array from my C# code. I don't want use ajax to send that element to an web service... I just want use an C# event, like OnClick and access the array that was build in javascript.
I searched for an answer but I just found the oposite.
Thanks

The easiest way is AJAX call and i don't understand why you are avoiding that ?
Make an AJAX call from your button click.
look here a demo :
Ajax call is not calling to the server side and in httpfox shows error as "Error loading content (NS_ERROR_DOCUMENT_NOT_CACHED)" in ajax post call
for example : covert your array to a json string and call a web client in your c# code. Here i have a button . on button click i want to send my GRIDVIEW data to c# method(web method).
you need to remember that while sending json data using stringfy() method,
in server side we need to define the parameter as object.
not any other format like string/int/bla bla.....
use Scripts/jquery-1.8.3.min.js
http://code.jquery.com/ui/1.10.3/jquery-ui.js
$('#btnResult').on('click', function () {
var mydata = [];
$("#<%=GridProjectDetails.ClientID %> tr").each(function () {
var myObject = new Object();
var id = $(this).find("input[name*='ID']").val();
var locationcode = $(this).find("input[name*='TextLocationCode']").val();
var Location = $(this).find("input[name*='TextLocation']").val();
myObject.id = id;
myObject.locationcode = locationcode;
myObject.Location = Location;
mydata.push(myObject);
});
var myString = JSON.stringify({ details: JSON.stringify(mydata) });
alert(myString);
var exportdata = myString;
$.ajax({
type: "POST",
url: "Default.aspx/ExportToExcel",
data: exportdata,
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (data) {
$("#Result").text(data.d);
},
error: function () { alert(arguments[2]); }
});
});
});
and server side method should be
[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Json)]
public static string ExportToExcel(object details)
{
return "Message : Success";
}

It's a kinda weird thing to do, but if you have to do it, you can do it by creating a form, inside the form have a hidden text field and call a function when submitting to update the value of this field.
The markup:
<form id="yourForm" method="post" >
<input type="text" name="hiddenFieldName" id="hiddenFieldName" hidden="hidden" />
</form>
The javascript:
void yourProcedure() {
var yourArray = ["Value1", "Value2", "Value3", "Value4"];
document.getElementById('hiddenFieldName').value = yourArray.join();
document.getElementById("yourForm").submit();
}
Then in the server, the form variable will contain "Value1,Value2,Value3,Value4".

display json data from controller inside view

Inside my controller there is JsonResult action which returns me a list of House object.
I want onclick using ajax to retrieve these data and to display json data inside my view.
Inside firebug I'm able to see proper Response and Json result but I dont know how to display inside my view.
function GetTabData(xdata) {
$.ajax({
url: ('/Home/GetTabData'),
type: 'POST',
contentType: 'application/json',
data: JSON.stringify({ id: xdata }),
success: function (result) {
// tried with these but it doesnt work
// result = jQuery.parseJSON(result);
// alert(result.Title);
},
error: function () { alert("error"); }
});
}
public JsonResult GetTabData()
{
...
var temp = getMyData...
return Json(temp, JsonRequestBehavior.AllowGet);
}
// View page
<div id="showContent">
// Json data should appear here
</div>
Inside firebug JSON tab when success:function(result) is empty
I have following data:
Id 149
PropertyType "Apartment"
StreetNumber "202B"
CityName "Sidney"
Title "My test data"

success: function (json) {
var data = null;
$.each(json.items,function(item,i){
data = '<div>'+item.Id+ ' ' + item.CityName +'</div>';
$("#showContent").append(data);
});
}

First of all, you can specify the dataType attribute in your ajax call to 'json' and then don't have to decode the json response again -
dataType: 'json'
Then, you don't need to use parseJSON. Simply use result.Title etc.
success: function (result) {
alert(result.Title);
var showContent = $('#showContent');
showContent.html(result.Id+','+result.Title);
},

EDIT: As Mukesh said, you can have the ajax function return json without using any extra decoding.
The ajax call result is already an object. You can do whatever you want with it it inside the success function.
For example you could create a table of the information dynamically inside the function, or send the data to another function by calling the function inside that success function. Once you leave the success function, the data is not usable anymore.
Access the data object like any object (data.someProperty).

jquery AJAX sent data in key value pair

In my aspx page, i have the js like this :-
<script language="javascript" type="text/javascript">
$("#btnLoad").click(function () {
var dataForAjax = "{'datakey':'hello'}"
$.ajax({
type: "POST",
url: "Ajax__Demo.aspx/SendFile",
data: dataForAjax,
success: function (msg) {
alert(msg); // Problem with this line. It is not showing the value.
}
});
});
</script>
In the same webpage code behind class file ,i have the webmethod defined like this:-
[WebMethod]
public static string SendFile(string key, string data)
{
return data;
}
For some reason, i am able to get the data in the alert used on the html side. alert(msg); is giving me nothing and i am expecting to get the passed value back. In this case it should be 'Hello'.
I am missing something very small here, please help me out here.

Alter these.
The AJAX Call
$(document).ready(function () {
$("#btnLoad").click(function (evt) {
var dataForAjax = "{'datakey':'hello'}";
$.ajax({
contentType: "application/json",
data: dataForAjax,
type: "POST",
url: 'Test1.aspx/SendFile',
success: function (msg) {
var msg = msg.hasOwnProperty("d") ? msg.d : msg;
alert(msg.datakey);
}
});
evt.preventDefault();
});
});
The WebMethod
[WebMethod]
public static object SendFile(string datakey)
{
return new
{
datakey = datakey
};
}
Hope this helps.
Update:
`evt.preventDefault is for preventing postback in case your control was something like input type="submit" or asp:Button
.d is ASP.NET 3.5+ feature to prevent XSS vulnerability. ( link here )
The return type is object for the web method for automatic serialization ( link here )
Also you could omitdataType in $.ajax call but contentType is an absolute necessity ( link here )

This:
var dataForAjax = "{'datakey':'hello'}"
Should be:
var dataForAjax = {'datakey':'hello'}
AJAX does not (by default anyway) send json - it sends FORM INPUT elements! jQuery is nice and will convert javascript objects into that for you.
If you really need to you can send json, but I really doubt you do, it's rare to do that.

When you send data to method you must send apropriate key-value pairs, using object in Javascript.
Examle for you method:
<script language="javascript" type="text/javascript">
$("#btnLoad").click(function () {
var dataForAjax = {'key' :'datakey', 'data' : 'hello'};
$.ajax({
type: "POST",
url: "Ajax__Demo.aspx/SendFile",
data: dataForAjax,
success: function (msg) {
alert(msg); // Problem with this line. It is not showing the value.
}
});
});