如何在MVC JsonResult中返回换行符

Question

I want to display a javascript alert using the message being passed back from a controller action that returns Json result. I want this message to have line breaks in it.

Here is my controller, note the "\\n" to input line breaks:

[HttpPost]
public JsonResult CreatePO(PONewViewModel viewModel)
{
    if (ModelState.IsValid)
    {
        var createPOResult = _managePOsAppServ
            .CreateNewPOHeaderAndDetail(CurrentFacilityId, CurrentUserId, viewModel.VendorId,
                viewModel.CustomerId, viewModel.OrderHeaderId, viewModel.ItemId, viewModel.QtyToOrder,
                viewModel.UnitCost);

        return Json(createPOResult, JsonRequestBehavior.AllowGet);
    }

    var modelStateErrors = this.ModelState.Keys.SelectMany(key => this.ModelState[key].Errors);
    string errorMessage = "";
    if (modelStateErrors.Count() > 0)
    {
        foreach (var error in modelStateErrors)
        {
            errorMessage += error.ErrorMessage + "\n";
        }
    }

    return Json(ActionConfirmation<int>.CreateFailureConfirmation(errorMessage, -1,false).Message, JsonRequestBehavior.AllowGet);
}

However, the \\n is being displayed in the alert box. So it seems the returned Json is escaping the \\n. How do I get it to be recognized as a line break?

Javascript:

xhr.onreadystatechange = function () {
    if (xhr.readyState == 4 && xhr.status == 200) {        
        alert(xhr.responseText);
        hideLoading();
    }
}

Answer 1

How are you alerting the data? Sounds like you're maybe alerting the JSON string, not the JavaScript string. Make sure you parse the JSON in your result by changing alert(xhr.responseText) to alert(jQuery.parseJSON(xhr.responseText));