return partial view from async method - ajax

Question

I've an async action method that return a partial view.
this action method called from a function with ajax.
my problem : when this method invoked every thing looks good except returned partial view.
I got error 500.
this is my action method Code :
[HttpPost]
public async Task<ActionResult> ChangeStateGroup(int[] lstCustomerServiceId, int newState)
{
int _counter = 0;
try
{
var _isOk = await CommonFunctions.ChangeState(_customerServiceId, _stateId, string.Empty);
if (_isOk)
{
//------do somthing
}
}
TempData[MyAlerts.SUCCESS] = string.Format("succeed Operation {0}", _counter);
}
catch (Exception ex)
{
TempData[MyAlerts.ERROR] = string.Format("Error: {0}", ex.Message);
}
return PartialView("_AlertsPartial");
}
and this is my jquery Code:
function postCustomerChangeStateGroup(lstCustomersId) {
var arrCustomersId = lstCustomersId.split(',');
$.ajax({
type: "POST",
url: "../Customer/ChangeStateGroup",
data: {
lstCustomerServiceId: arrCustomersId,
newState: $("#fk_state").val()
},
success: function (data) {
if (data.indexOf("error") !== -1) {
$("#inlineAlert_Wrapper").append(data);
}
else {
getCustomerReport();
$('#modal-container').modal('toggle');
$("#alert_Wrapper").append(data);
}
},
failure: function (errMsg) {
alert("An Error Accoured: " + errMsg);
}
});
}

Answer 1

Partial views cannot be asynchronous in ASP.NET pre-Core. You can have asynchronous partial views in ASP.NET Core.
So, your options are:
Update to ASP.NET Core.
Remove the asynchronous code and make it synchronous instead.

Answer 2

Error 500 means the error inside of the action.It maybe because ot the empty input parameters. Check them in debugger and if they are empty,
try to use application/json content type,sometimes it works better
$.ajax({
type: "POST",
contentType: "application/json; charset=utf-8",
url: "/Customer/ChangeStateGroup",
data: JSON.stringify( {
lstCustomerServiceId: arrCustomersId,
newState: $("#fk_state").val()
}),
success: function (data) {
....
create viewModel
public class ViewModel
{
public int[] lstCustomerServiceId {get; set;}
public int newState {get; set;}
}
and fix the action
public async Task<ActionResult> ChangeStateGroup([FromBody] ViewModel model)