AJAX Callback using POST method - asp.net

Question

I require some assistance. I am using jQuery to cause an ajax callback:
function TestingCallback(controlId) {
if (controlId == 'drpControl') {
var options = {
type: "POST",
url: "Main.aspx",
data: { drpControl: $(".drpControl").val() },
//contentType: "application/json; charset=utf-8",
//cache: false,
success: function (data) {
},
complete: function (jqXHR, status) {
formData = $("#form1").serialize();
window.location = "Main.aspx?" + formData;
ShowLoadingBar();
return false;
}
};
var resp = $.ajax(options);
}
}
And the backend I get the data like so:
Request.Form["drpControl"], which works well.
But as soon as I add this line to the callback options : contentType: "application/json; charset=utf-8",, I get a value of null for Request.Form["drpControl"].
Please assist on how to overcome this.
Thanks in advance
Might I just add that I am trying to cause a postback but keep all control values, hence this line :
formData = $("#form1").serialize();
window.location = "Main.aspx?" + formData;
But after a second postback (on change of drpControl) field values gets cleared, I am assuming this has to do with IE not being able to cater for a long querystring, I have tested it in Chrome and it works perfect, but not IE, and I need it to work for IE 8.Any suggestions?

Answer 1

in content type just add this
contentType: "application/json"
Designating the encoding is somewhat redundant for JSON, since the default encoding for JSON is UTF-8. So in this case the receiving server apparently is happy knowing that it's dealing with JSON and assumes that the encoding is UTF-8 by default, that's why it works with or without the header.
contentType (default: 'application/x-www-form-urlencoded; charset=UTF-8')-
When sending data to the server, use this content type. Default is "application/x-www-form-urlencoded; charset=UTF-8", which is fine for most cases. If you explicitly pass in a content-type to $.ajax(), then it'll always be sent to the server (even if no data is sent). If no charset is specified, data will be transmitted to the server using the server's default charset; you must decode this appropriately on the server side.
Note sure but pass data like this
data: "{'drpControl' : " + $(".drpControl").val()+ "}",