我正在尝试创建一个asp应用程序，在那里我可以编写出发地和目的地城市。我想在此文本框中实现Google AutoComplete。
我开发了异步方法，当您插入一个或多个名为'getAutoComplete'的字母时，会返回google的自动完成功能。
现在我想通过我的javascript访问它，带有ajax请求。
这是我的aspx代码
<%@ Page Async="true" Title="Home Page" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="googleApiWeb._Default" %>
<asp:Content runat="server" ID="BodyContent" ContentPlaceHolderID="MainContent">
<ol class="round">
<div id="DEPARTURE_CITY" style="margin-top: 15px; margin-left: 15px;">
<asp:Label ID="lblDepartureCity" runat="server" Text="Ville de départ"></asp:Label>
<asp:TextBox runat="server" ID="txbDepartureCity" ClientIDMode="Static" Style="width: 150px;"></asp:TextBox>
</div>
<div id="DESTINATION_CITY" style="margin-top: 15px; margin-left: 15px;">
<asp:Label ID="lblDestinationCity" runat="server" Text="Ville d'arrivé"></asp:Label>
<asp:TextBox runat="server" ID="txbDestinationCity" ClientIDMode="Static" Style="width: 150px;"></asp:TextBox>
</div>
<asp:Button ID="buttonValider" runat="server" Text="Valider" ClientIDMode="Static" OnClick="buttonValider_Click" />
<asp:Label ID="lbl1" runat="server" Text=""></asp:Label>
<asp:Label ID="lbl2" runat="server" Text=""></asp:Label>
</ol>
<script type="text/javascript">
$(document).ready(function () {
//Autocomplete
$("#txbDepartureCity").bind("change paste keyup", function () {
$.ajax({
type: "POST",
url: "/Default.aspx/getAutoComplete",
data: "{'Element':'" + $(this).val() + "'}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (response) {
alert(response.d);
}
});
});
$("#txbDestinationCity").bind("change paste keyup", function () {
$.ajax({
type: "POST",
url: "/Default/googleAutoComplete",
data: "{'Element':'" + $(this).val() + "'}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (response) {
if (response.d == "NOK") {
//errorResponseAlert();
}
}
});
});
});
</script>
现在我的代码
namespace googleApiWeb
{
public partial class _Default : Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
#region WebMethod autocomplete GoogleApi
[WebMethod(EnableSession = true)]
public static string googleAutoComplete(string Element)
{
string x = getAutoComplete(Element);
return "";
}
[WebMethod(EnableSession = true)]
private static async Task<string> getAutoComplete(string Element)
{
// Adresse à compléter
string location = Element;
// Message d'erreur s'il y en a
string error = "";
// Créer une instance d'auto complete
AutoComplete autoComplete = new AutoComplete();
// Options de l'auto complete
AutoCompleteOptions options = new AutoCompleteOptions()
{
// Obtenir les résultats en français
Language = LanguageEnum.French,
// Pays dans lequel vous souhaitez limiter vos résultats
// Attention : format ISO 3166-1 : "us", "fr", "de", ...
CountryFilter = "fr",
// Type de résultats à retourner.
// Ex : Regions retourne le code postal, ce que ne fait pas Cities.
// Si cette option est vide, tous les résultats sont retournés.
TypeFilter = TypeFilterEnum.Regions
};
// Clé API
string key = "XXXXXXX";
// Appel asynchrone de la méthode de la dll
var listOfLocation = await autoComplete.GetAutoComplete(location, key, null).ContinueWith(t =>
{
// S'il y a une erreur
if (t.IsFaulted)
{
// Message de l'exception
error = t.Exception.InnerException.Message;
return null;
}
// Résultat
return t.Result;
});
var result = listOfLocation.First();
return result;
}
#endregion
protected void buttonValider_Click(object sender, EventArgs e)
{
GetTrip();
getAutoComplete(txbDepartureCity.Text);
}
}
}
，错误为POST http://localhost:51460/Default.aspx/getAutoComplete 500 (Internal Server Error)
我如何管理这个，以便在我的方法的结果上获得ajax成功函数。这样做的目的是获得没有回调的结果。
谢谢
答案 0 :(得分：1)
好的，所以我想出了如何解决这个问题。为了在ajax中调用web方法，web方法必须返回一个字符串。所以这个方法不能是异步的。
我在
后面的代码中添加了这个类public static class AsyncHelpers
{
/// <summary>
/// Execute's an async Task<T> method which has a void return value synchronously
/// </summary>
/// <param name="task">Task<T> method to execute</param>
public static void RunSync(Func<Task> task)
{
var oldContext = SynchronizationContext.Current;
var synch = new ExclusiveSynchronizationContext();
SynchronizationContext.SetSynchronizationContext(synch);
synch.Post(async _ =>
{
try
{
await task();
}
catch (Exception e)
{
synch.InnerException = e;
throw;
}
finally
{
synch.EndMessageLoop();
}
}, null);
synch.BeginMessageLoop();
SynchronizationContext.SetSynchronizationContext(oldContext);
}
/// <summary>
/// Execute's an async Task<T> method which has a T return type synchronously
/// </summary>
/// <typeparam name="T">Return Type</typeparam>
/// <param name="task">Task<T> method to execute</param>
/// <returns></returns>
public static T RunSync<T>(Func<Task<T>> task)
{
var oldContext = SynchronizationContext.Current;
var synch = new ExclusiveSynchronizationContext();
SynchronizationContext.SetSynchronizationContext(synch);
T ret = default(T);
synch.Post(async _ =>
{
try
{
ret = await task();
}
catch (Exception e)
{
synch.InnerException = e;
throw;
}
finally
{
synch.EndMessageLoop();
}
}, null);
synch.BeginMessageLoop();
SynchronizationContext.SetSynchronizationContext(oldContext);
return ret;
}
private class ExclusiveSynchronizationContext : SynchronizationContext
{
private bool done;
public Exception InnerException { get; set; }
readonly AutoResetEvent workItemsWaiting = new AutoResetEvent(false);
readonly Queue<Tuple<SendOrPostCallback, object>> items =
new Queue<Tuple<SendOrPostCallback, object>>();
public override void Send(SendOrPostCallback d, object state)
{
throw new NotSupportedException("We cannot send to our same thread");
}
public override void Post(SendOrPostCallback d, object state)
{
lock (items)
{
items.Enqueue(Tuple.Create(d, state));
}
workItemsWaiting.Set();
}
public void EndMessageLoop()
{
Post(_ => done = true, null);
}
public void BeginMessageLoop()
{
while (!done)
{
Tuple<SendOrPostCallback, object> task = null;
lock (items)
{
if (items.Count > 0)
{
task = items.Dequeue();
}
}
if (task != null)
{
task.Item1(task.Item2);
if (InnerException != null) // the method threw an exeption
{
throw new AggregateException("AsyncHelpers.Run method threw an exception.", InnerException);
}
}
else
{
workItemsWaiting.WaitOne();
}
}
}
public override SynchronizationContext CreateCopy()
{
return this;
}
}
现在我的网络方法
[WebMethod(EnableSession = true)]
public static string googleAutoComplete(string Element)
{
string result = "";
List<string> lstReturnGoogle = AsyncHelpers.RunSync<List<string>>(() => getAutoComplete(Element));
if (lstReturnGoogle != null)
{
result = "[";
foreach (string t in lstReturnGoogle)
{
result += '"' + t + '"' + ',';
}
result = result.Remove(result.Length - 1, 1);
result += "]";
result.Replace('\\', ' ');
}
return result;
}
有了这个，我可以在ajax中调用我的Webmethod，并得到正确的答案。