ASP.NET

• return the exception (what I do)
• return en empty response body?
• return an empty of default JSON object?
• something else?

<input type="button" value="Export" onclick="location.href='@Url.Action("Export", "Home")'" />

public ActionResult Export()
{
    var data = _dal.GetDashboardInfos(new DashboardInfoQueryArgs());
    var d = data.ToList().ToCsv();

    var path = Path.GetTempPath();
    var fileData = string.Format("{0}ardexport.csv", path);

    using (StreamWriter sw = new StreamWriter(fileData, false))
    {
        sw.WriteLine(d);
    }

    Process.Start(fileData);

    return View("Index", "Home");
}

The view 'Index' or its master was not found or no view engine supports the searched locations. The following locations were searched:
.
.
.

$("#btnSave").click(function () {
    var defaultText = $("#defaultText").val();
    var txtLanId = $("#txtLanId").val();
    var txtLast = $("#txtLast").val();
    var txtFirst = $("#txtFirst").val();
    var txtEmployeeId = $("#txtEmployeeId").val();
    var txtEmail = $("#txtEmail").val();

    var dtFieldHireDate = $("#dtFieldHireDate").val();
    var dtFieldRehireDate = $("#dtFieldRehireDate").val();
    var lbxApplicationGroup = $("#lbxApplicationGroup").val();
    var lbxReportPack = $("#lbxReportPack").val();

    alert(dtFieldHireDate);
    alert(dtFieldRehireDate);
    alert(lbxApplicationGroup);
    alert(lbxReportPack);

    $.ajax({
url: "/api/EmployeeAPI",
type: "Post",
data: JSON.stringify([defaultText, txtLanId, txtLast, txtFirst, txtEmployeeId, txtEmail, dtFieldHireDate, dtFieldRehireDate, lbxApplicationGroup, lbxReportPack]),
contentType: 'application/json; charset=utf-8',
success: function (data) { },
error: function () { alert('error'); }
    });
});

[System.Web.Http.HttpPost]
public string PostAction(System.Net.Http.Formatting.FormDataCollection form)
{
    string retValues;   
    retValues = form.Get("txtLast") + form.Get("txtLanId");

    return retValues;
}