我正在 ASP.NET MVC 中开发一个房地产 Web 应用程序。我的问题出在我的预订部分。
我正在使用 AJAX 在返回 JSONResult
的 Controller 中发布。这是我的代码:
Controller
[HttpPost]
public JsonResult SubmitReservation(ReservationViewModel rvm)
{
return Json(rvm, JsonRequestBehavior.AllowGet);
}
主要 AJAX
var rvm = new ReservationViewModel();
getBuyerInfo(rvm.SelectedBuyerID, clientCallback);
getSiteInfo(rvm.SelectedSiteID, siteCallback);
getUnitInfo(rvm.SelectedUnitID, unitCallback);
$.ajax({
url: "/Reservations/SubmitReservation",
data: JSON.stringify(rvm),
type: "POST",
dataType: "json",
contentType: "application/json",
success: function () {
console.log(clientData);
console.log(siteData);
console.log(unitData);
//Assignment of data to different output fields
//Client Data
$('#clientName').html(clientData.FullName);
$('#clientAddress').html(clientData.Residence);
$('#clientContact').html(clientData.ContactNumber);
//Site Data
$('#devSite').html(siteData.SiteName);
$('#devLoc').html(siteData.Location);
////House Unit Data
$('#unitBlock').html(unitData.Block);
$('#unitLot').html(unitData.Lot);
$('#modelName').html(unitData.ModelName);
$('#modelType').html(unitData.TypeName);
$('#lotArea').html(unitData.LotArea);
$('#floorArea').html(unitData.FloorArea);
$('#unitBedrooms').html(unitData.NumberOfBedrooms);
$('#unitBathrooms').html(unitData.NumberOfBathrooms);
$('#unitPrice').html(unitData.Price);
$('#reservationDetails').show();
alert("Success!");
},
error: function (err) {
alert("Error: " + err);
}
});
获取数据的函数
function getBuyerInfo(id, cb) {
$.ajax({
url: "/BuyersInformation/GetBuyerByID/" + id,
type: "GET",
contentType: "application/json",
dataType: "json",
success: cb
});
}
function getSiteInfo(id, cb) {
$.ajax({
url: "/Sites/GetSiteByID/" + id,
type: "GET",
contentType: "application/json",
dataType: "json",
success: cb
});
}
function getUnitInfo(id, cb) {
$.ajax({
url: "/HouseUnits/GetUnitByID/" + id,
type: "GET",
contentType: "application/json",
dataType: "json",
success: cb
});
}
function ReservationViewModel() {
var buyerId = $('#SelectedBuyerID').val();
var siteId = $('#SelectedSiteID').val();
var unitId = $('#SelectedUnitID').val();
var rsvDate = $('#ReservationDate').val();
var me = this;
me.ReservationDate = rsvDate;
me.SelectedBuyerID = buyerId;
me.SelectedSiteID = siteId;
me.SelectedUnitID = unitId;
}
function clientCallback(result) {
clientInfo = result;
clientData = clientInfo[0];
}
function siteCallback(result) {
siteInfo = result;
siteData = siteInfo[0];
}
function unitCallback(result) {
unitInfo = result;
unitData = unitInfo[0];
}
整个代码第二次运行良好。然而,它第一次不起作用。当我刷新页面并点击“创建”时,它返回未定义。但是当我再次点击该按钮而不刷新页面时,它运行良好。有人可以向我解释一下这个吗?为什么 AJAX 最初返回 undefined 而在后续调用时不返回?提前致谢。
最佳答案
您正在代码中的这些函数内调用多个 ajax 请求:
getBuyerInfo(rvm.SelectedBuyerID, clientCallback);
getSiteInfo(rvm.SelectedSiteID, siteCallback);
getUnitInfo(rvm.SelectedUnitID, unitCallback);
最后是$.ajax({...})
,您可以在其中使用之前的 ajax 调用的结果。
您的问题是,第一个 ajax 调用不一定会在启动最后一个 ajax 之前返回结果,因为它们都是异步的。在调用最后一个 ajax 之前,您必须确保收到三个响应。使用 Promise 或 jQuery when
,如下所示:
var rvm = new ReservationViewModel();
$.when(
$.ajax({
url: "/BuyersInformation/GetBuyerByID/" + rvm.SelectedBuyerID,
type: "GET",
contentType: "application/json",
dataType: "json"
}),
$.ajax({
url: "/Sites/GetSiteByID/" + rvm.SelectedSiteID,
type: "GET",
contentType: "application/json",
dataType: "json"
}),
$.ajax({
url: "/HouseUnits/GetUnitByID/" + rvm.SelectedUnitID,
type: "GET",
contentType: "application/json",
dataType: "json"
})
).done(function ( clientResponse, siteResponse, unitResponse ) {
clientInfo = clientResponse;
clientData = clientInfo[0];
siteInfo = siteResponse;
siteData = siteInfo[0];
unitInfo = unitResponse;
unitData = unitInfo[0];
$.ajax({ ... }) // your last ajax call
});
关于javascript - AJAX GET 在第一次调用时返回未定义,但在第二次调用时有效,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/34984531/