Chiamata a servizi Web da script client
Aggiornamento: novembre 2007
In questo argomento viene illustrato come utilizzare la funzionalità AJAX di ASP.NET per chiamare un servizio Web da ECMAScript (JavaScript). Per consentire all'applicazione di chiamare servizi Web ASP.NET tramite script client, il livello di comunicazione del servizio Web del server genera automaticamente classi proxy JavaScript. Viene generata una classe proxy per ogni servizio Web a cui si fa riferimento mediante un elemento ServiceReference nel controllo ScriptManager della pagina.
I servizi Web possono essere servizi Web ASP.NET (ASMX) o servizi°Windows Communication Foundation (WCF) (SVC). Se sono già stati creati servizi Web ASP.NET (ASMX), è possibile modificarli per consentirne la chiamata da parte di script nelle pagine Web con supporto AJAX. Per ulteriori informazioni, vedere Esposizione di servizi Web a script client. Se sono già stati creati servizi WCF, è possibile aggiungere endpoint per consentirne l'accesso da parte di script nelle pagine Web con supporto AJAX. Per ulteriori informazioni, vedere Esposizione di servizi WCF a script client.
Per chiamare un metodo del servizio Web, chiamare il metodo corrispondente della classe proxy JavaScript generata. La classe proxy comunica a sua volta con il servizio Web.
Chiamata ai metodi del servizio Web
La chiamata a un metodo del servizio Web da script è asincrona. Per ottenere un valore restituito o determinare quando la richiesta ha restituito un valore, è necessario fornire una funzione di callback riuscita. La funzione di callback viene richiamata una volta eseguita correttamente la richiesta e contiene il valore restituito (se presente) dalla chiamata al metodo Web. È anche possibile fornire una funzione di callback non riuscita per gestire gli errori. Inoltre è possibile passare le informazioni sul contesto utente da utilizzare nelle funzioni di callback.
Nell'esempio riportato di seguito viene illustrata l'esecuzione dei seguenti tipi di chiamate ai servizi Web:
Chiamata a un servizio Web privo di valore restituito.
Chiamata a un servizio Web che restituisce un valore.
Chiamata a un metodo del servizio Web che accetta parametri.
Chiamata a un metodo del servizio Web tramite verbo HTTP GET.
Chiamata a un metodo del servizio Web che restituisce un oggetto XmlDocument.
Nella prima parte dell'esempio viene illustrata una pagina Web che esegue chiamate al servizio tramite script client.
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" >
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
<title>Calling Web Methods</title>
</head>
<body>
<form id="Form1" >
<asp:ScriptManager ID="scriptManagerId">
<Scripts>
<asp:ScriptReference Path="CallWebServiceMethods.js" />
</Scripts>
<Services>
<asp:ServiceReference Path="WebService.asmx" />
</Services>
</asp:ScriptManager>
<div>
<h2>Calling Web Methods</h2>
<table>
<tr align="left">
<td>Method that does not return a value:</td>
<td>
<!-- Getting no retun value from
the Web service. -->
<button id="Button1"
onclick="GetNoReturn()">No Return</button>
</td>
</tr>
<tr align="left">
<td>Method that returns a value:</td>
<td>
<!-- Getting a retun value from
the Web service. -->
<button id="Button2"
onclick="GetTime(); return false;">Server Time</button>
</td>
</tr>
<tr align="left">
<td>Method that takes parameters:</td>
<td>
<!-- Passing simple parameter types to
the Web service. -->
<button id="Button3"
onclick="Add(20, 30); return false;">Add</button>
</td>
</tr>
<tr align="left">
<td>Method that returns XML data:</td>
<td>
<!-- Get Xml. -->
<button id="Button4"
onclick="GetXmlDocument(); return false;">Get Xml</button>
</td>
</tr>
<tr align="left">
<td>Method that uses GET:</td>
<td>
<!-- Making a GET Web request. -->
<button id="Button5"
onclick="MakeGetRequest(); return false;">Make GET Request</button>
</td>
</tr>
</table>
</div>
</form>
<hr/>
<div>
<span id="ResultId"></span>
</div>
</body>
</html>
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" >
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
<title>Calling Web Methods</title>
</head>
<body>
<form id="Form1" >
<asp:ScriptManager ID="scriptManagerId">
<Scripts>
<asp:ScriptReference Path="CallWebServiceMethods.js" />
</Scripts>
<Services>
<asp:ServiceReference Path="WebService.asmx" />
</Services>
</asp:ScriptManager>
<div>
<h2>Calling Web Methods</h2>
<table>
<tr align="left">
<td>Method that does not return a value:</td>
<td>
<!-- Getting no retun value from
the Web service. -->
<button id="Button1"
onclick="GetNoReturn()">No Return</button>
</td>
</tr>
<tr align="left">
<td>Method that returns a value:</td>
<td>
<!-- Getting a retun value from
the Web service. -->
<button id="Button2"
onclick="GetTime(); return false;">Server Time</button>
</td>
</tr>
<tr align="left">
<td>Method that takes parameters:</td>
<td>
<!-- Passing simple parameter types to
the Web service. -->
<button id="Button3"
onclick="Add(20, 30); return false;">Add</button>
</td>
</tr>
<tr align="left">
<td>Method that returns XML data:</td>
<td>
<!-- Get Xml. -->
<button id="Button4"
onclick="GetXmlDocument(); return false;">Get Xml</button>
</td>
</tr>
<tr align="left">
<td>Method that uses GET:</td>
<td>
<!-- Making a GET Web request. -->
<button id="Button5"
onclick="MakeGetRequest(); return false;">Make GET Request</button>
</td>
</tr>
</table>
</div>
</form>
<hr/>
<div>
<span id="ResultId"></span>
</div>
</body>
</html>
Nella parte successiva dell'esempio viene illustrato lo script client utilizzato dalla pagina Web per chiamare il servizio Web.
// This function calls the Web service method without
// passing the callback function.
function GetNoReturn()
{
Samples.AspNet.WebService.GetServerTime();
alert("This method does not return a value.");
}
// This function calls the Web service method and
// passes the event callback function.
function GetTime()
{
Samples.AspNet.WebService.GetServerTime(
SucceededCallback);
}
// This function calls the Web service method
// passing simple type parameters and the
// callback function
function Add(a, b)
{
Samples.AspNet.WebService.Add(a, b,
SucceededCallback);
}
// This function calls the Web service method
// that returns an XmlDocument type.
function GetXmlDocument()
{
Samples.AspNet.WebService.GetXmlDocument(
SucceededCallbackWithContext, FailedCallback,
"XmlDocument")
}
// This function calls a Web service method that uses
// GET to make the Web request.
function MakeGetRequest()
{
Samples.AspNet.WebService.EchoStringAndDate(
new Date("1/1/2007"), " Happy",
SucceededCallback,
FailedCallback, "HappyNewYear");
}
// This is the callback function invoked if the Web service
// succeeded.
// It accepts the result object, the user context, and the
// calling method name as parameters.
function SucceededCallbackWithContext(result, userContext, methodName)
{
var output;
// Page element to display feedback.
var RsltElem = document.getElementById("ResultId");
var readResult;
if (userContext == "XmlDocument")
{
if (document.all)
readResult =
result.documentElement.firstChild.text;
else
// Firefox
readResult =
result.documentElement.firstChild.textContent;
RsltElem.innerHTML = "XmlDocument content: " + readResult;
}
}
// This is the callback function invoked if the Web service
// succeeded.
// It accepts the result object as a parameter.
function SucceededCallback(result, eventArgs)
{
// Page element to display feedback.
var RsltElem = document.getElementById("ResultId");
RsltElem.innerHTML = result;
}
// This is the callback function invoked if the Web service
// failed.
// It accepts the error object as a parameter.
function FailedCallback(error)
{
// Display the error.
var RsltElem =
document.getElementById("ResultId");
RsltElem.innerHTML =
"Service Error: " + error.get_message();
}
if (typeof(Sys) !== "undefined") Sys.Application.notifyScriptLoaded();
Nella parte successiva viene illustrato il servizio Web chiamato dalla pagina.
<%@ WebService Language="VB" Class="Samples.AspNet.WebService" %>
Imports System.Web
Imports System.Web.Services
Imports System.Xml
Imports System.Web.Services.Protocols
Imports System.Web.Script.Services
Namespace Samples.AspNet
<WebService(Namespace:="http://tempuri.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<ScriptService()> _
Public Class WebService
Inherits System.Web.Services.WebService
Private _xmlString As String = _
"<?xml version=""1.0"" encoding=""utf-8"" ?>" + _
" <message>" + _
" <content>" + _
" Welcome to the asynchronous communication layer world!" + _
" </content>" + _
" </message>"
' This method returns an XmlDocument type.
<WebMethod()> _
<ScriptMethod(ResponseFormat:=ResponseFormat.Xml)> _
Public Function GetXmlDocument() As XmlDocument
Dim xmlDoc As New XmlDocument()
xmlDoc.LoadXml(_xmlString)
Return xmlDoc
End Function 'GetXmlDocument
' This method uses GET instead of POST.
' Its input parameters are sent by the
' client in the URL query string.
<WebMethod()> _
<ScriptMethod(UseHttpGet:=True)> _
Public Function EchoStringAndDate(ByVal dt As DateTime, _
ByVal s As String) As String
Return s + ":" + dt.ToString()
End Function 'EchoStringAndDate
<WebMethod()> _
Public Function GetServerTime() As String
Dim serverTime As String = _
String.Format("The current time is {0}.", DateTime.Now)
Return serverTime
End Function 'GetServerTime
<WebMethod()> _
Public Function Add(ByVal a As Integer, _
ByVal b As Integer) As String
Dim addition As Integer = a + b
Dim result As String = _
String.Format("The addition result is {0}.", addition.ToString())
Return result
End Function 'Add
<WebMethod()> _
<ScriptMethod(ResponseFormat:=ResponseFormat.Xml, _
XmlSerializeString:=True)> _
Public Function GetString() As String
Return "Hello World"
End Function
End Class 'WebService
End Namespace
<%@ WebService Language="C#" Class="Samples.AspNet.WebService" %>
using System;
using System.Web;
using System.Web.Services;
using System.Xml;
using System.Web.Services.Protocols;
using System.Web.Script.Services;
namespace Samples.AspNet
{
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[ScriptService]
public class WebService : System.Web.Services.WebService
{
private string _xmlString =
@"<?xml version=""1.0"" encoding=""utf-8"" ?>
<message>
<content>
Welcome to the asynchronous communication layer world!
</content>
</message>";
// This method returns an XmlDocument type.
[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Xml)]
public XmlDocument GetXmlDocument()
{
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(_xmlString);
return xmlDoc;
}
// This method uses GET instead of POST.
// For this reason its input parameters
// are sent by the client in the
// URL query string.
[WebMethod]
[ScriptMethod(UseHttpGet = true)]
public string EchoStringAndDate(DateTime dt, string s)
{
return s + ":" + dt.ToString();
}
[WebMethod]
public string GetServerTime()
{
string serverTime =
String.Format("The current time is {0}.", DateTime.Now);
return serverTime;
}
[WebMethod]
public string Add(int a, int b)
{
int addition = a + b;
string result =
String.Format("The addition result is {0}.",
addition.ToString());
return result;
}
[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Xml,
XmlSerializeString = true)]
public string GetString()
{
return "Hello World";
}
}
}
Specifica delle funzioni di callback come proprietà predefinite
Negli esempi precedenti le chiamate ai metodi del servizio Web vengono eseguite utilizzando la classe proxy. Le informazioni sulla funzione di callback riuscita, sulla funzione di callback non riuscita e sul contesto utente vengono passate utilizzando parametri aggiuntivi nella chiamata.
In alternativa, è possibile specificare una funzione di callback riuscita, una funzione di callback non riuscita e il contesto utente come proprietà predefinite per la classe. Lo script può quindi richiamare i metodi del servizio Web della classe proxy senza passare questi valori sotto forma di parametri nella chiamata. In questo modo la sintassi della chiamata ai metodi del servizio Web viene semplificata.
Nell'esempio seguente viene illustrato come impostare le proprietà predefinite sulla classe proxy del servizio Web e successivamente chiamare un metodo del servizio Web.
MyNameSpace.MyService.set_defaultSucceededCallback(SucceededCallback);
MyNameSpace.MyService.set_defaultFailedCallback(FailedCallback);
MyNameSpace.MyService.set_defaultUserContext("my context");
MyNameSpace.MyService.myServiceMethod(param1, param2);
Impostazione delle funzioni di callback come proprietà delle istanze della classe proxy
È anche possibile creare istanze della classe proxy generata. In tal caso, è possibile specificare una funzione di callback riuscita, una funzione di callback non riuscita e il contesto utente come proprietà predefinite per ciascuna istanza. Come accade per la chiamata alla classe proxy generata, è quindi possibile utilizzare le istanze della classe proxy per chiamare i metodi del servizio Web senza passare questi valori sotto forma di parametri nella chiamata.
In genere, le istanze della classe proxy vengono create quando si desidera effettuare più chiamate ai metodi del servizio Web e utilizzare valori delle proprietà predefiniti diversi per ogni istanza. Ad esempio, è possibile specificare funzioni di callback diverse per ciascuna istanza. Utilizzando funzioni di callback diverse, è possibile elaborare i dati restituiti in modi diversi in base alle esigenze dell'applicazione e alla natura dei dati.
Nell'esempio seguente viene illustrato come creare un'istanza di una classe proxy, impostarne le proprietà predefinite e chiamare il metodo del servizio Web correlato:
var myServiceProxy = new MyNameSpace.MyService();
myServiceProxy.set_defaultSucceededCallback(SuccededCallback);
myServiceProxy.set_defaultFailedCallback(FailedCallback);
MyNameSpce.MyService.set_defaultUserContext("my context");
myServiceProxy.myServiceMethod(param1, param2);
Per ulteriori informazioni, vedere Classi proxy generate.
Gestione degli errori nelle chiamate ai metodi del servizio Web
Per rilevare gli errori è necessario fornire una funzione di callback non riuscita che accetta un solo parametro. Questo parametro conterrà l'oggetto errore inviato dal servizio Web.
Nell'esempio seguente viene illustrato come fornire una funzione di callback non riuscita che viene chiamata se si verifica un errore durante la chiamata a un metodo del servizio Web. Nella prima parte dell'esempio viene illustrata una pagina Web che chiama un servizio Web tramite script client.
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script >
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" >
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
<title>Handling Web Service Error</title>
</head>
<body>
<form id="Form1" >
<asp:ScriptManager ID="scriptManagerId">
<Scripts>
<asp:ScriptReference Path="WebServiceMethodError.js" />
</Scripts>
<Services>
<asp:ServiceReference Path="WebService.asmx" />
</Services>
</asp:ScriptManager>
<div>
<h2>Handling Web Service Error</h2>
<table>
<tr align="left">
<td>Method with error:</td>
<td>
<!-- Cause divide by zero failure. -->
<button id="Button1"
onclick="Div(10, 0); return false;">Div Error</button>
</td>
</tr>
</table>
</div>
</form>
<hr/>
<div>
<span id="Results"></span>
</div>
</body>
</html>
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" >
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
<title>Handling Web Service Error</title>
</head>
<body>
<form id="Form1" >
<asp:ScriptManager ID="scriptManagerId">
<Scripts>
<asp:ScriptReference Path="WebServiceMethodError.js" />
</Scripts>
<Services>
<asp:ServiceReference Path="WebService.asmx" />
</Services>
</asp:ScriptManager>
<div>
<h2>Handling Web Service Error</h2>
<table>
<tr align="left">
<td>Method with error:</td>
<td>
<!-- Cause divide by zero failure. -->
<button id="Button1"
onclick="Div(10, 0); return false;">Div Error</button>
</td>
</tr>
</table>
</div>
</form>
<hr/>
<div>
<span id="Results"></span>
</div>
</body>
</html>
Nella parte successiva dell'esempio viene illustrato lo script client utilizzato dalla pagina per chiamare il servizio Web.
// This function can cause a divide by zero error.
function Div(a, b)
{
Samples.AspNet.WebService.Div(a, b,
SucceededCallback, FailedCallback);
}
// This is the failed callback function.
function FailedCallback(error)
{
var stackTrace = error.get_stackTrace();
var message = error.get_message();
var statusCode = error.get_statusCode();
var exceptionType = error.get_exceptionType();
var timedout = error.get_timedOut();
// Display the error.
var RsltElem =
document.getElementById("Results");
RsltElem.innerHTML =
"Stack Trace: " + stackTrace + "<br/>" +
"Service Error: " + message + "<br/>" +
"Status Code: " + statusCode + "<br/>" +
"Exception Type: " + exceptionType + "<br/>" +
"Timedout: " + timedout;
}
// This is the succeeded callback function.
function SucceededCallback(result)
{
// Display the result.
var RsltElem = document.getElementById("Results");
RsltElem.innerHTML = result;
}
if (typeof(Sys) !== "undefined") Sys.Application.notifyScriptLoaded();
Nella parte successiva viene illustrato il servizio Web chiamato dalla pagina.
<%@ WebService Language="VB" Class="Samples.AspNet.WebService" %>
Imports System.Web
Imports System.Web.Services
Imports System.Xml
Imports System.Web.Services.Protocols
Imports System.Web.Script.Services
Namespace Samples.AspNet
<WebService(Namespace:="http://tempuri.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<ScriptService()> _
Public Class WebService
Inherits System.Web.Services.WebService
<WebMethod()> _
Public Function Div(ByVal a As Integer, _
ByVal b As Integer) As String
Dim division As Integer = a / b
Dim result As String = _
String.Format("The division result is {0}.", division.ToString())
Return result
End Function 'Div
End Class 'WebService
End Namespace
<%@ WebService Language="C#" Class="Samples.AspNet.WebService" %>
using System;
using System.Web;
using System.Web.Services;
using System.Xml;
using System.Web.Services.Protocols;
using System.Web.Script.Services;
namespace Samples.AspNet
{
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[ScriptService]
public class WebService : System.Web.Services.WebService
{
[WebMethod]
public string Div(int a, int b)
{
int division = a / b;
string result =
String.Format("The division result is {0}.",
division.ToString());
return result;
}
}
}
Chiamata di un'unica funzione di callback da più metodi del servizio Web
È possibile fornire un'unica funzione di callback riuscita che viene richiamata da più metodi del servizio Web. Affinché la funzione possa distinguere i diversi chiamanti, è possibile passarle il contesto utente o, in alternativa, verificare il nome del metodo chiamante. Il contesto utente e il nome del metodo chiamante sono entrambi disponibili nella funzione di callback.
Nell'esempio seguente viene illustrato come chiamare un'unica funzione di callback da più richieste del servizio Web. Nella prima parte dell'esempio viene illustrata una pagina Web che chiama un servizio Web tramite script client.
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" >
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
<title>Passing user context or method name</title>
</head>
<body>
<form id="Form1" >
<asp:ScriptManager ID="scriptManager">
<Services>
<asp:ServiceReference Path="WebService_VB.asmx" />
</Services>
<Scripts>
<asp:ScriptReference Path="WebServiceMultipleCallers.js" />
</Scripts>
</asp:ScriptManager>
<div>
<h2>Passing User Context or Method Name</h2>
<table>
<tr align="left">
<td>Passing user context:</td>
<td>
<button id="Button1"
onclick="AddWithContext(10, 20, 'user context information'); return false;">User Context</button>
</td>
</tr>
<tr align="left">
<td>Passing method:</td>
<td>
<button id="Button7"
onclick="AddWithMethod(10, 30); return false;">Method Name</button>
</td>
</tr>
</table>
</div>
</form>
<hr/>
<div>
<span id="Results"></span>
</div>
</body>
</html>
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" >
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
<title>Passing user context or method name</title>
</head>
<body>
<form id="Form1" >
<asp:ScriptManager ID="scriptManager">
<Services>
<asp:ServiceReference Path="WebService.asmx" />
</Services>
<Scripts>
<asp:ScriptReference Path="WebServiceMultipleCallers.js" />
</Scripts>
</asp:ScriptManager>
<div>
<h2>Passing User Context or Method Name</h2>
<table>
<tr align="left">
<td>Passing user context:</td>
<td>
<button id="Button1"
onclick="AddWithContext(10, 20, 'user context information'); return false;">User Context</button>
</td>
</tr>
<tr align="left">
<td>Passing method:</td>
<td>
<button id="Button7"
onclick="AddWithMethod(10, 30); return false;">Method Name</button>
</td>
</tr>
</table>
</div>
</form>
<hr/>
<div>
<span id="Results"></span>
</div>
</body>
</html>
Nella parte successiva dell'esempio viene illustrato lo script client utilizzato dalla pagina Web per chiamare il servizio Web.
// This function calls a Web service method
// passing simple type parameters and the user context.
function AddWithContext(a, b, userContext)
{
Samples.AspNet.WebService.Add(a, b,
SucceededCallbackWithContext, FailedCallback, userContext, null);
}
// This function calls the Web service method
// passing the method name.
function AddWithMethod(a, b)
{
Samples.AspNet.WebService.Add(a, b,
SucceededCallbackWithContext, FailedCallback);
}
// This is the callback function called if the
// Web service succeeded. It accepts the result
// object, the user context, and the method name as
// parameters.
function SucceededCallbackWithContext(result, userContext, methodName)
{
// It holds feedback message.
var output = "";
// Page element to display the feedback message.
var RsltElem =
document.getElementById("Results");
if (userContext)
{
output += "The user context is : " + userContext + "<br/>";
RsltElem.innerHTML = output;
return;
}
if (methodName)
output += "The method name is : " + methodName + "<br/>";
RsltElem.innerHTML = output;
}
// This is the callback function called if the
// Web service failed. It accepts the error object
// as a parameter.
function FailedCallback(error)
{
// Display the error.
var RsltElem =
document.getElementById("Results");
RsltElem.innerHTML =
"Service Error: " + error.get_message();
}
if (typeof(Sys) !== "undefined") Sys.Application.notifyScriptLoaded();
Nella parte successiva viene illustrato il servizio Web chiamato dalla pagina.
<%@ WebService Language="VB" Class="Samples.AspNet.WebService" %>
Imports System.Web
Imports System.Web.Services
Imports System.Xml
Imports System.Web.Services.Protocols
Imports System.Web.Script.Services
Namespace Samples.AspNet
<WebService(Namespace:="http://tempuri.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<ScriptService()> _
Public Class WebService
Inherits System.Web.Services.WebService
<WebMethod()> _
Public Function Add(ByVal a As Integer, _
ByVal b As Integer) As String
Dim addition As Integer = a + b
Dim result As String = _
String.Format("The addition result is {0}.", addition.ToString())
Return result
End Function 'Add
End Class 'WebService
End Namespace
<%@ WebService Language="C#" Class="Samples.AspNet.WebService" %>
using System;
using System.Web;
using System.Web.Services;
using System.Xml;
using System.Web.Services.Protocols;
using System.Web.Script.Services;
namespace Samples.AspNet
{
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[ScriptService]
public class WebService : System.Web.Services.WebService
{
[WebMethod]
public string Add(int a, int b)
{
int addition = a + b;
string result =
String.Format("The addition result is {0}.",
addition.ToString());
return result;
}
}
}
Passaggio e restituzione di tipi complessi
Se il metodo del servizio Web restituisce un tipo complesso, la funzione di callback riuscita riceve un valore restituito sotto forma di oggetto JavaScript corrispondente al tipo di server.
Nell'esempio seguente viene illustrato un metodo del servizio Web che restituisce un tipo complesso. Nella prima parte dell'esempio viene illustrata una pagina Web che chiama un servizio Web tramite script client.
<%@ Page Language="VB" %>
<%@ Import Namespace="System.Web.Script.Serialization" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" >
<title>Receiving Complex Type</title>
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
</head>
<body>
<h2>Receiving Complex Type</h2>
<form id="form1" >
<asp:ScriptManager ID="scriptManager">
<Services>
<asp:ServiceReference Path="HandleColor.asmx" />
</Services>
<Scripts>
<asp:ScriptReference Path="HandleColor.js" />
</Scripts>
</asp:ScriptManager>
<table style="font-size:12px">
<tr>
<td>Web Service Default Color:</td>
<td>
<button id="Button1"
onclick="GetDefaultColor(); return false;">Get Default Color</button>
</td>
</tr>
</table>
<hr />
<!-- Display current color object. -->
<p>
<span style="background-color:Yellow">Color:</span>
<span id="ResultId"></span>
</p>
</form>
</body>
</html>
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" >
<title>Receiving Complex Type</title>
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
</head>
<body>
<h2>Receiving Complex Type</h2>
<form id="form1" >
<asp:ScriptManager ID="scriptManager">
<Services>
<asp:ServiceReference Path="HandleColor.asmx" />
</Services>
<Scripts>
<asp:ScriptReference Path="HandleColor.js" />
</Scripts>
</asp:ScriptManager>
<table style="font-size:12px">
<tr>
<td>Web Service Default Color:</td>
<td>
<button id="Button1"
onclick="GetDefaultColor(); return false;">Get Default Color</button>
</td>
</tr>
</table>
<hr />
<!-- Display current color object. -->
<p>
<span style="background-color:Yellow">Color:</span>
<span id="ResultId"></span>
</p>
</form>
</body>
</html>
Nella parte successiva dell'esempio viene illustrato lo script client utilizzato dalla pagina per chiamare il servizio Web.
// It gets the default color
// from the Web service.
function GetDefaultColor()
{
// Call the Web service method to get
// the default color.
Samples.AspNet.HandleColor.GetDefaultColor(
SucceededCallback);
}
// This is the callback function that
// processes the complex type returned
// by the Web service.
function SucceededCallback(result)
{
// Read the values returned by the
// Web service.
var message = result.message;
var rgb = result.rgb;
var timeStamp = result.timeStamp;
// Transform the rgb array into a string.
var serverColor = rgb[0]+ rgb[1] + rgb[2];
// Display the result.
var displayResult =
document.getElementById("ResultId");
displayResult.style.color = "yellow";
displayResult.style.fontWeight = "bold";
if (document.all)
displayResult.innerText = message + " " + timeStamp;
else
// Firefox
displayResult.textContent = message + " " + timeStamp;
displayResult.style.backgroundColor = "#" + serverColor;
}
if (typeof(Sys) !== "undefined") Sys.Application.notifyScriptLoaded();
Nella parte successiva viene illustrato il servizio Web chiamato dalla pagina.
<%@ WebService Language="VB" Class="Samples.AspNet.HandleColor" %>
Imports System.Web
Imports System.Web.Services
Imports System.Web.Services.Protocols
Imports System.Web.Script.Services
Imports System.Web.Script.Serialization
Namespace Samples.AspNet
' Define the color object to
' exchange with the client.
Public Class ColorObject
Public message As String = "The default color is Blue."
Public rgb() As String = {"00", "00", "FF"}
Public timeStamp As String
End Class 'ColorObject
<WebService([Namespace]:="http://tempuri.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<GenerateScriptType(GetType(ColorObject))> _
<ScriptService()> _
Public Class HandleColor
Inherits System.Web.Services.WebService
<WebMethod()> _
Public Function GetDefaultColor() As ColorObject
' Instantiate the default color object.
Dim co As New ColorObject()
' Set time stamp.
co.timeStamp = DateTime.Now.ToString()
Return co
End Function 'GetDefaultColor
<WebMethod()> _
Public Function ChangeDefaultColor( _
ByVal color As ColorObject) As ColorObject
' Instantiate the default color object.
Dim co As New ColorObject()
' Assign the passed values.
co.message = color.message
co.rgb = color.rgb
' Set time stamp.
co.timeStamp = DateTime.Now.ToString()
Return co
End Function 'ChangeDefaultColor
End Class 'HandleColor
End Namespace
<%@ WebService Language="C#" Class="Samples.AspNet.HandleColor" %>
using System;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Web.Script.Services;
using System.Web.Script.Serialization;
namespace Samples.AspNet
{
// Define the color object to
// exchange with the client.
public class ColorObject
{
public string message =
"The default color is Blue.";
public string[] rgb =
new string[] { "00", "00", "FF" };
public string timeStamp;
}
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[GenerateScriptType(typeof(ColorObject))]
[ScriptService]
public class HandleColor :
System.Web.Services.WebService
{
[WebMethod]
public ColorObject GetDefaultColor()
{
// Instantiate the default color object.
ColorObject co = new ColorObject();
// Set time stamp.
co.timeStamp = DateTime.Now.ToString();
return co;
}
[WebMethod]
public ColorObject ChangeDefaultColor(ColorObject color)
{
// Instantiate the default color object.
ColorObject co = new ColorObject();
// Assign the passed values.
co.message = color.message;
co.rgb = color.rgb;
// Set time stamp.
co.timeStamp = DateTime.Now.ToString();
return co;
}
}
}
Nell'esempio seguente viene illustrato come chiamare metodi del servizio Web che possiedono parametri corrispondenti a tipi complessi. Le classi proxy per i tipi saranno generate automaticamente. In questo modo lo script client può creare istanze del tipo da passare sotto forma di parametri alla chiamata al metodo.
Nella prima parte dell'esempio viene illustrata una pagina Web che chiama un servizio Web tramite script client.
<%@ Page Language="VB" %>
<%@ Import Namespace="System.Web.Script.Serialization" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" >
<title>Exchanging Complex Types</title>
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
</head>
<body>
<h2>Exchanging Complex Types</h2>
<form id="form1" >
<asp:ScriptManager ID="scriptManager">
<Services>
<asp:ServiceReference Path="HandleColor.asmx" />
</Services>
<Scripts>
<asp:ScriptReference Path="HandleColor.js" />
</Scripts>
</asp:ScriptManager>
</form>
<center>
<table style="font-size:12px;" >
<tr align="center">
<td class="text">Change Color:</td>
<td>
<select id="ColorSelectID"
onchange="OnChangeDefaultColor(this);" >
</select>
</td>
</tr>
</table>
</center>
<hr />
<!-- Display current color object. -->
<span style="background-color:Yellow">Color:</span>
<span id="ResultId"></span>
</body>
</html>
<%@ Page Language="C#" %>
<%@ Import Namespace="System.Web.Script.Serialization" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" >
<title>Exchanging Complex Types</title>
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
</head>
<body>
<h2>Exchanging Complex Types</h2>
<form id="form1" >
<asp:ScriptManager ID="scriptManager">
<Services>
<asp:ServiceReference Path="HandleColor.asmx" />
</Services>
<Scripts>
<asp:ScriptReference Path="HandleColor.js" />
</Scripts>
</asp:ScriptManager>
</form>
<center>
<table style="font-size:12px;" >
<tr align="center">
<td class="text">Change Color:</td>
<td>
<select id="ColorSelectID"
onchange="OnChangeDefaultColor(this);" >
</select>
</td>
</tr>
</table>
</center>
<hr />
<!-- Display current color object. -->
<span style="background-color:Yellow">Color:</span>
<span id="ResultId"></span>
</body>
</html>
Nella parte successiva dell'esempio viene illustrato lo script client utilizzato dalla pagina Web per chiamare il servizio Web.
// The Web service default color.
var defaultRgb;
// The page feedback display element.
var displayResult;
// Gets the selection list colors and
// the default color from the Web service.
function GetServerColors()
{
// Gets the default color.
Samples.AspNet.HandleColor.GetDefaultColor(
SucceededCallback, FailedCallback);
// Get selection list colors.
Samples.AspNet.HandleColor.GetColorList(
SucceededCallback, FailedCallback);
}
// This function passes the color selected
// by the user (client) to the Web service.
function OnChangeDefaultColor(comboObject)
{
// Create an instance
// of the server color object.
var color =
new Samples.AspNet.ColorObject();
// Get the user's selected color.
var selectionIndex =
comboObject.selectedIndex;
var selectedColor =
comboObject.options[selectionIndex].text;
// Get the related RGB color value.
var selectionValue =
comboObject.value;
// Transform it into an array.
var colorArray = selectionValue.split(",");
// Assign the new values to
// the server color object.
color.message = "The new default color is " + selectedColor + ".";
color.rgb = colorArray;
// Call the Web service method to change the color.
Samples.AspNet.HandleColor.ChangeDefaultColor(
color, SucceededCallback, FailedCallback);
}
// This is the callback function that processes
// the complex type returned by the Web service.
function SucceededCallback(result, userContext, methodName)
{
switch(methodName)
{
case ("GetColorList"):
{
// Get the select object.
var selectObject = document.getElementById("ColorSelectID");
var i = 0;
// Iterate through the dictionary to populate
// the selection list.
for(var item in result)
{
var option = new Option(result[item], item);
selectObject.options[i]=option;
// Set the default selection.
if (item == defaultRgb)
selectObject.options[i].selected = true;
i++;
}
break;
}
default:
{
// Get the server default color and its current time.
// Read the values returned by the
// Web service.
var message = result.message;
defaultRgb = result.rgb;
var timeStamp = result.timeStamp;
// Transform the rgb array into a string.
var serverColor = defaultRgb[0]+ defaultRgb[1] + defaultRgb[2];
// Display the result.
displayResult.style.color = "yellow";
displayResult.style.fontWeight = "bold";
if (document.all)
displayResult.innerText = message + " " + timeStamp;
else
// Firefox
displayResult.textContent = message + " " + timeStamp;
displayResult.style.backgroundColor = "#" + serverColor;
break;
}
}
}
// Callback function invoked on failure
// of the Web service methods.
function FailedCallback(error, userContext, methodName)
{
if(error !== null)
{
displayResult.innerHTML = "An error occurred: " +
error.get_message();
}
}
// Gets the Web service selection list colors
// and the default color.
function pageLoad()
{
// Get page feedback display element.
displayResult =
document.getElementById("ResultId");
// Get the server's selection list colors and
// the default color.
GetServerColors();
}
if (typeof(Sys) !== "undefined") Sys.Application.notifyScriptLoaded();
Nella parte successiva viene illustrato il servizio Web chiamato dalla pagina.
<%@ WebService Language="C#" Class="Samples.AspNet.HandleColor" %>
using System;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Web.Script.Services;
using System.Web.Script.Serialization;
using System.Collections.Generic;
namespace Samples.AspNet
{
// Define the color object to
// exchange with the client.
public class ColorObject
{
public string message;
public string[] rgb;
public string timeStamp;
public ColorObject()
{
this.message = "The default color is Red.";
this.rgb = new string[] { "FF", "00", "00" };
this.timeStamp = DateTime.Now.ToString();
}
}
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[GenerateScriptType(typeof(ColorObject))]
[ScriptService]
public class HandleColor :
System.Web.Services.WebService
{
[WebMethod]
public ColorObject GetDefaultColor()
{
// Instantiate the default color object.
ColorObject co = new ColorObject();
return co;
}
[WebMethod]
public ColorObject ChangeDefaultColor(ColorObject color)
{
// Instantiate the default color object.
ColorObject co = new ColorObject();
// Assign the passed values.
co.message = color.message;
co.rgb = color.rgb;
// Set time stamp.
co.timeStamp = DateTime.Now.ToString();
return co;
}
[WebMethod]
public Dictionary<String,String> GetColorList()
{
//Instatiate the dictionary object.
Dictionary<String, String> result = new Dictionary<string, string>();
//Add the color items.
result.Add("00,00,FF", "Blue");
result.Add("FF,00,00", "Red");
result.Add("00,FF,00", "Green");
result.Add("00,00,00", "Black");
return result;
}
}
}
Passaggio di parametri tipizzati come generics o matrici
Un metodo del servizio Web può supportare parametri o un valore restituito tipizzati come generics o come matrici di elenchi di tipo T. In tal caso, ASP.NET genera automaticamente le classi proxy per il tipo T da utilizzare con lo script client.
Tuttavia, se un tipo generico accetta più argomenti del tipo, ad esempio Dictionary<string, <T>>, ASP.NET non genera automaticamente le classi proxy per i tipi. Affinché ASP.NET generi una classe proxy per il tipo T, la classe del servizio Web che utilizza il tipo deve essere qualificata con l'attributo GenerateScriptTypeAttribute per il tipo T.
Nell'esempio seguente viene illustrato come chiamare un metodo del servizio Web da script client quando i parametri sono tipizzati come generics o matrici. Nella prima parte dell'esempio viene illustrata una pagina Web che chiama un servizio Web tramite script client.
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" >
<title>Using Generics Proxy Types</title>
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 10pt Trebuchet MS; text-align: center }
</style>
</head>
<body>
<h2>Using Generics Proxy Types</h2>
<form id="form1" >
<asp:ScriptManager ID="scriptManager">
<Services>
<asp:ServiceReference Path="WebService.asmx" />
<asp:ServiceReference Path="WebService2.asmx" />
</Services>
<Scripts>
<asp:ScriptReference Path="generics.js" />
</Scripts>
</asp:ScriptManager>
</form>
<center>
<table style="font-size:12px;" >
<tr align="left">
<td class="text">Generic List:</td>
<td>
<button id="Button1"
onclick="GenericList()">Get List</button>
</td>
</tr>
<tr align="left">
<td class="text">Generic Dictionary:</td>
<td>
<button id="Button2"
onclick="GenericDictionary()">Get Dictionary</button>
</td>
</tr>
<tr align="left">
<td class="text">Generic Custom Type Dictionary:</td>
<td>
<button id="Button3"
onclick="GenericCustomTypeDictionary()">Get Dictionary</button>
</td>
</tr>
<tr align="left">
<td class="text">Generic Dictionary:</td>
<td>
<button id="Button5"
onclick="PassGenericDictionary()">Pass Dictionary</button>
</td>
</tr>
<tr align="left">
<td class="text">Array:</td>
<td>
<button id="Button4"
onclick="ArrayType()">Get Array</button>
</td>
</tr>
</table>
</center>
<hr />
<!-- Display current color object. -->
<span id="ResultId"></span>
</body>
</html>
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" >
<title>Using Generics Proxy Types</title>
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 10pt Trebuchet MS; text-align: center }
</style>
</head>
<body>
<h2>Using Generics Proxy Types</h2>
<form id="form1" >
<asp:ScriptManager ID="scriptManager">
<Services>
<asp:ServiceReference Path="WebService.asmx" />
<asp:ServiceReference Path="WebService2.asmx" />
</Services>
<Scripts>
<asp:ScriptReference Path="generics.js" />
</Scripts>
</asp:ScriptManager>
</form>
<center>
<table style="font-size:12px;" >
<tr align="left">
<td class="text">Generic List:</td>
<td>
<button id="Button1"
onclick="GenericList()">Get List</button>
</td>
</tr>
<tr align="left">
<td class="text">Generic Dictionary:</td>
<td>
<button id="Button2"
onclick="GenericDictionary()">Get Dictionary</button>
</td>
</tr>
<tr align="left">
<td class="text">Generic Custom Type Dictionary:</td>
<td>
<button id="Button3"
onclick="GenericCustomTypeDictionary()">Get Dictionary</button>
</td>
</tr>
<tr align="left">
<td class="text">Generic Dictionary:</td>
<td>
<button id="Button5"
onclick="PassGenericDictionary()">Pass Dictionary</button>
</td>
</tr>
<tr align="left">
<td class="text">Array:</td>
<td>
<button id="Button4"
onclick="ArrayType()">Get Array</button>
</td>
</tr>
</table>
</center>
<hr />
<!-- Display current color object. -->
<span id="ResultId"></span>
</body>
</html>
Nella parte successiva dell'esempio viene illustrato lo script client utilizzato dalla pagina Web per chiamare il servizio Web.
// The page feedback display element.
var displayResult;
// This function intializes the global variables and
// assigns default values to the generated proxy.
function pageLoad()
{
// Get page feedback display element.
displayResult =
document.getElementById("ResultId");
// Assign default values to the generated proxy.
Samples.AspNet.TestService.set_defaultUserContext("Default context");
Samples.AspNet.TestService.set_defaultSucceededCallback(SucceededCallback);
Samples.AspNet.TestService.set_defaultFailedCallback(FailedCallback);
}
// Get a generic List.
function GenericList()
{
Samples.AspNet.TestService.GetGenericList();
}
// Get a generic Dictionary.
function GenericDictionary()
{
Samples.AspNet.TestService.GetGenericDictionary();
}
// Get a generic Dictionary of custom types.
function GenericCustomTypeDictionary()
{
Samples.AspNet.TestService.GetGenericCustomTypeDictionary();
}
// Pass a generic dictionary of custom types
// to Webservice.
function PassGenericDictionary()
{
var simple = new Samples.AspNet.SimpleClass2();
simple.s = "WebService proxy.";
Samples.AspNet.TestService.PassGenericDictionary(
{"first":simple});
}
// Get an Array.
function ArrayType()
{
Samples.AspNet.TestService.GetArray();
}
// Callback function invoked when the call to
// the Web service methods succeeds.
function SucceededCallback(result, userContext, methodName)
{
var message;
switch(methodName)
{
case ("GetGenericList"):
{
var i = 0;
var message = new Array();
for(var item in result)
{
message[i] = "List element " + i + ": " + result[item].s;
i++;
}
DisplayMessage(message.toString());
break;
}
case ("GetGenericDictionary"):
{
var i = 0;
var message = new Array();
for(var item in result)
{
message[i] = item + ": " + result[item];
i++;
}
DisplayMessage(message.toString());
break;
}
case ("GetGenericCustomTypeDictionary"):
{
var i = 0;
var message = new Array();
for(var item in result)
{
message[i] = item + ": " + result[item].s;
i++;
}
DisplayMessage(message.toString());
break;
}
case ("PassGenericDictionary"):
{
DisplayMessage(result);
break;
}
case ("GetArray"):
{
var i = 0;
var message = new Array();
for(var item in result)
{
message[i] = result[item];
i++;
}
DisplayMessage(message.toString());
break;
}
default:
{
DisplayMessage("Method unknown");
}
}
}
// Callback function invoked when the call to
// the Web service methods fails.
function FailedCallback(error, userContext, methodName)
{
if(error !== null)
{
displayResult.innerHTML = "An error occurred: " +
error.get_message();
}
}
function DisplayMessage(message)
{
if (document.all)
displayResult.innerText = message;
else
// Firefox
displayResult.textContent = message;
}
if (typeof(Sys) !== "undefined") Sys.Application.notifyScriptLoaded();
Nella parte successiva viene illustrato il servizio Web chiamato dalla pagina.
<%@ WebService Language="C#" Class="Samples.AspNet.TestService" %>
namespace Samples.AspNet
{
using System;
using System.Collections;
using System.Collections.Generic;
using System.Web.Services;
using System.Web.Script.Services;
// Custom type used by WebService.
public class SimpleClass
{
private string _s = "SimpleClass1";
public String s {
get { return _s; }
set { _s = value; }
}
}
// Custom type used by WebService.
public class SimpleClass2
{
private string _s = "SimpleClass2";
public String s
{
get { return _s; }
set { _s = value; }
}
}
// The following service allows the generation
// of the SimpleClass2 type proxy by applying the
// attribute: GenerateScriptType. This assures
// that the a SimpleClass2 object can be
// passed by the client script to the
// PassGenericDictionary method.
// Note if you comment out the GenerateScriptType
// you get an error because the SimpleClass2 type proxy
// is not generated.
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[GenerateScriptType(typeof(SimpleClass2))]
[ScriptService]
public class TestService : System.Web.Services.WebService
{
// The following method return a list of SimpleClass
// objects.
// Note the SimpleClass type proxy is automatically
// generated because used in the return parameter.
[WebMethod]
[ScriptMethod(UseHttpGet = false, ResponseFormat = ResponseFormat.Json)]
public List<SimpleClass> GetGenericList()
{
List<SimpleClass> GetGenericList = new List<SimpleClass>();
SimpleClass simple1 = new SimpleClass();
SimpleClass simple2 = new SimpleClass();
simple1.s = "Generics first instance";
simple2.s = "Generics second instance";
GetGenericList.Add(simple1);
GetGenericList.Add(simple2);
return GetGenericList;
}
// The following method return a Dictionary of strings.
[WebMethod]
public Dictionary<String, String> GetGenericDictionary()
{
//Instantiate the dictionary object.
Dictionary<String, String> result =
new Dictionary<string, string>();
//Add items.
result.Add("0000FF", "Blue");
result.Add("FF0000", "Red");
result.Add("00FF00", "Green");
result.Add("000000", "Black");
return result;
}
// The following method return a Dictionary of
// SimpleClass objects.
// Note the SimpleClass type proxy object is automatically
// generated because used in the return parameter.
[WebMethod]
public Dictionary<String, SimpleClass> GetGenericCustomTypeDictionary()
{
//Instantiate the dictionary object.
Dictionary<String, SimpleClass> result =
new Dictionary<string, SimpleClass>();
SimpleClass simple = new SimpleClass();
simple.s = "custom type instance";
//Add items.
result.Add("Custom type", simple);
return result;
}
// The following method accept a Dictionary of
// SimpleClass2 objects.
// Note the SimpleClass2 type proxy object is
// not automatically generated because used in
// an input parameter. You must enable its
// generation by applying the GenerateScriptType
// attribute to the service.
[WebMethod]
public String PassGenericDictionary(
Dictionary<string, SimpleClass2> d)
{
string value = d["first"].s;
string message = "Dictionary element value: " + value;
return message;
}
// This function returns an array.
[WebMethod]
public ArrayList GetArray()
{
//Instantiate the array object.
ArrayList result = new ArrayList();
//Add items.
result.Add("First element: " + "Test1");
result.Add("Second element: " + "Test2");
return result;
}
}
}
Passaggio di parametri tipizzati come enumeratori
Un tipo enumeratore è accessibile tramite la classe proxy automaticamente generata.
.gif "Nota") Nota: |
|---|
Non creare un'istanza della classe proxy generata per accedere agli enumeratori. |
Nell'esempio seguente viene illustrato come chiamare un metodo del servizio Web da script client quando i parametri sono tipizzati come enumeratori. Nella prima parte dell'esempio viene illustrata una pagina Web che chiama un servizio Web tramite script client.
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" >
<title>Using Generated Proxy Types</title>
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 10pt Trebuchet MS; text-align: center }
</style>
</head>
<body>
<h2>Using Generated Proxy Types</h2>
<form id="form1" >
<asp:ScriptManager ID="scriptManager">
<Services>
<asp:ServiceReference Path="ServerTypes.asmx" />
</Services>
<Scripts>
<asp:ScriptReference Path="ServerTypes.js" />
</Scripts>
</asp:ScriptManager>
</form>
<center>
<table style="font-size:12px;" >
<tr align="left">
<td class="text">Get Enum:</td>
<td>
<button id="Button2"
onclick="GetSelectedEnumValue()">Get Enum Value</button>
</td>
</tr>
<tr align="left">
<td class="text">Pass Enum:</td>
<td>
<button id="Button1"
onclick="GetFirstEnumElement()">First Enum</button>
</td>
</tr>
</table>
</center>
<hr />
<!-- Display current color object. -->
<span id="ResultId"></span>
</body>
</html>
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" >
<title>Using Generated Proxy Types</title>
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 10pt Trebuchet MS; text-align: center }
</style>
</head>
<body>
<h2>Using Generated Proxy Types</h2>
<form id="form1" >
<asp:ScriptManager ID="scriptManager">
<Services>
<asp:ServiceReference Path="ServerTypes.asmx" />
</Services>
<Scripts>
<asp:ScriptReference Path="ServerTypes.js" />
</Scripts>
</asp:ScriptManager>
</form>
<center>
<table style="font-size:12px;" >
<tr align="left">
<td class="text">Get Enum:</td>
<td>
<button id="Button2"
onclick="GetSelectedEnumValue()">Get Enum Value</button>
</td>
</tr>
<tr align="left">
<td class="text">Pass Enum:</td>
<td>
<button id="Button1"
onclick="GetFirstEnumElement()">First Enum</button>
</td>
</tr>
</table>
</center>
<hr />
<!-- Display current color object. -->
<span id="ResultId"></span>
</body>
</html>
Nella parte successiva dell'esempio viene illustrato lo script client utilizzato dalla pagina Web per chiamare il servizio Web.
// ServerTypes.js
// The Web service default color.
var defaultRgb;
// The page feedback display element.
var displayResult;
// Gets the Web service selection list colors
// and the default color.
function pageLoad()
{
// Get page feedback display element.
displayResult =
document.getElementById("ResultId");
// Assign default values for the generated proxy using
// the (generated) static proxy.
Samples.AspNet.ServerTypes.set_timeout(200);
Samples.AspNet.ServerTypes.set_defaultUserContext("Default context");
Samples.AspNet.ServerTypes.set_defaultSucceededCallback(SucceededCallback);
Samples.AspNet.ServerTypes.set_defaultFailedCallback(FailedCallback);
}
// This function shows how to get an
// enumeration object from the server.
function GetFirstEnumElement()
{
// Get the first element of the enumeration
Samples.AspNet.ServerTypes.GetFirstColor();
}
// This function shows how to pass an
// enumeration value to the server.
function GetSelectedEnumValue()
{
// Get the value of the selected enumerated
// element.
Samples.AspNet.ServerTypes.GetSelectedColor(
Samples.AspNet.ColorEnum.Blue);
}
// Callback function invoked when the call to
// the Web service methods succeeds.
function SucceededCallback(result, userContext, methodName)
{
var message;
switch(methodName)
{
case ("GetFirstColor"):
{
var firstColor = result;
message = "First enumerated value: " + firstColor;
DisplayMessage(message);
break;
}
default:
{
DisplayMessage("Method unknown");
}
}
}
// Callback function invoked when the call to
// the Web service methods fails.
function FailedCallback(error, userContext, methodName)
{
if(error !== null)
{
displayResult.innerHTML = "An error occurred: " +
error.get_message();
}
}
function DisplayMessage(message)
{
if (document.all)
displayResult.innerText = message;
else
// Firefox
displayResult.textContent = message;
}
if (typeof(Sys) !== "undefined") Sys.Application.notifyScriptLoaded();
Nella parte successiva viene illustrato il servizio Web chiamato dalla pagina.
<%@ WebService Language="VB" Class="Samples.AspNet.ServerTypes" %>
Imports System
Imports System.Web
Imports System.Web.Services
Imports System.Web.Services.Protocols
Imports System.Web.Script.Services
Imports System.Web.Script.Serialization
Imports System.Collections.Generic
Namespace Samples.AspNet
' Define the enum type to
' exchange with the client.
Public Enum ColorEnum
Red = 0
Green = 1
Blue = 2
End Enum
<WebService(Namespace:="http://tempuri.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<ScriptService()> _
Public Class ServerTypes
Inherits System.Web.Services.WebService
' The enum type can be accessed by the client
' script through the generated Web service
' proxy class in a static fashion.
<WebMethod()> _
Public Function GetFirstColor() As ColorEnum
' Return the first color
' in the enumeration.
Return ColorEnum.Red
End Function
<WebMethod()> _
Public Function GetSelectedColor(ByVal color As ColorEnum) As String
' Return the selected color value
' in the enumeration.
Return color.ToString()
End Function
End Class
End Namespace
<%@ WebService Language="C#" Class="Samples.AspNet.ServerTypes" %>
using System;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Web.Script.Services;
using System.Web.Script.Serialization;
using System.Collections.Generic;
namespace Samples.AspNet
{
// Define the enum type to
// exchange with the client.
public enum ColorEnum
{
Red = 0,
Green = 1,
Blue = 2
}
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[ScriptService]
public class ServerTypes :
System.Web.Services.WebService
{
// The enum type can be accessed by the client
// script through the generated Web service
// proxy class in a static fashion.
[WebMethod]
public ColorEnum GetFirstColor()
{
// Return the first color
// in the enumeration.
return ColorEnum.Red;
}
[WebMethod]
public string GetSelectedColor(ColorEnum color)
{
// Return the selected color value
// in the enumeration.
return color.ToString();
}
}
}
Chiamata a operazioni dei servizi WCF
Windows Communication Foundation (WCF) è il modello di programmazione unificato di Microsoft per la compilazione di applicazioni orientate ai servizi. Supporta ASP.NET AJAX e il formato dati JSON (JavaScript Object Notation). Questo consente ai servizi WCF di esporre operazioni alle pagine Web che eseguono il codice JavaScript e possono pertanto accedere ai servizi tramite richieste HTTP.
Se sono già stati creati servizi WCF, è possibile aggiungere endpoint per consentirne l'accesso da parte dello script nelle pagine Web con supporto AJAX.
La chiamata a un'operazione del servizio Windows Communication Foundation (WCF),°ossia un termine WCF per un metodo, da script è asincrona. Come accade con altre procedure asincrone, viene fornita una funzione di callback riuscita°che viene richiamata una volta terminata la richiesta. È anche possibile fornire una funzione di callback non riuscita per gestire gli errori. Per ulteriori informazioni sui servizi Windows Communication Foundation (WCF) e sul relativo hosting in ASP.NET, vedere ASP.NET AJAX Integration and JSON Support (informazioni in lingua inglese).
Nell'esempio seguente viene illustrato come compilare un servizio WCF e chiamare i relativi metodi tramite script client in uno script della pagina Web. Nella prima parte dell'esempio viene illustrato come eseguire chiamate al servizio tramite script client.
<%@ Page Language="VB" AutoEventWireup="true" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head >
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
<title>Simple WCF Service Page</title>
</head>
<body>
<form id="form1" >
<asp:ScriptManager ID="ScriptManager1" >
<Services>
<asp:ServiceReference
Path="SimpleService.svc/ws"/>
</Services>
<Scripts>
<asp:ScriptReference Path="service.js" />
</Scripts>
</asp:ScriptManager>
<div>
<h2>Simple WCF Service</h2>
<input type='button' name="clickme" value="Greetings"
onclick="javascript:OnClick()" />
<input type='button' name="clickme2" value="Greetings2"
onclick="javascript:OnClick2()" />
<hr/>
<div>
<span id="Results"></span>
</div>
</div>
</form>
</body>
</html>
<%@ Page Language="C#" AutoEventWireup="true"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head >
<style type="text/css">
body { font: 11pt Trebuchet MS;
font-color: #000000;
padding-top: 72px;
text-align: center }
.text { font: 8pt Trebuchet MS }
</style>
<title>Simple WCF Service Page</title>
</head>
<body>
<form id="form1" >
<asp:ScriptManager ID="ScriptManager1" >
<Services>
<asp:ServiceReference
Path="SimpleService.svc/ws"/>
</Services>
<Scripts>
<asp:ScriptReference Path="service.js" />
</Scripts>
</asp:ScriptManager>
<div>
<h2>Simple WCF Service</h2>
<input type='button' name="clickme" value="Greetings"
onclick="javascript:OnClick()" />
<input type='button' name="clickme2" value="Greetings2"
onclick="javascript:OnClick2()" />
<hr/>
<div>
<span id="Results"></span>
</div>
</div>
</form>
</body>
</html>
Nella parte successiva dell'esempio viene illustrato lo script client utilizzato dalla pagina Web per chiamare il servizio Web.
var ServiceProxy;
function pageLoad()
{
ServiceProxy = new ISimpleService();
ServiceProxy.set_defaultSucceededCallback(SucceededCallback);
}
function OnClick()
{
// var myService = new ISimpleService();
ServiceProxy.HelloWorld1("George");
}
function OnClick2()
{
var dc = new DataContractType();
dc.FirstName = "George";
dc.LastName = "Washington";
ServiceProxy.HelloWorld2(dc);
}
// This is the callback function that
// processes the Web Service return value.
function SucceededCallback(result, userContext, methodName)
{
var RsltElem = document.getElementById("Results");
RsltElem.innerHTML = result + " from " + methodName + ".";
}
if (typeof(Sys) !== "undefined") Sys.Application.notifyScriptLoaded();
Nella parte successiva viene illustrato il servizio Web chiamato dalla pagina.
Imports System
Imports System.Web
Imports System.Collections
Imports System.Collections.Generic
Imports System.Threading
Imports System.Xml
Imports System.Xml.Serialization
Imports System.Text
Imports System.IO
Imports System.Runtime.Serialization
Imports System.ServiceModel
Imports System.ServiceModel.Description
Imports System.ServiceModel.Dispatcher
Imports System.ServiceModel.Channels
Imports System.ServiceModel.Activation
' This a WCF service which consists of a contract,
' defined below as ISimpleService, and DataContractType,
' a class which implements that interface, see SimpleService,
' and configuration entries that specify behaviors associated with
' that implementation (see <system.serviceModel> in web.config)
Namespace Aspnet.Samples.SimpleService
<ServiceContract()> _
Public Interface ISimpleService
<OperationContract()> _
Function HelloWorld1(ByVal value1 As String) As String
<OperationContract()> _
Function HelloWorld2(ByVal dataContractValue1 _
As DataContractType) As String
End Interface 'ISimpleService
<ServiceBehavior(IncludeExceptionDetailInFaults:=True), _
AspNetCompatibilityRequirements(RequirementsMode:= _
AspNetCompatibilityRequirementsMode.Allowed)> _
Public Class SimpleService
Implements ISimpleService
Public Sub New()
End Sub 'New
Public Function HelloWorld1(ByVal value1 As String) As String _
Implements ISimpleService.HelloWorld1
Return "Hello " + value1
End Function 'HelloWorld1
Public Function HelloWorld2(ByVal dataContractValue1 _
As DataContractType) As String _
Implements ISimpleService.HelloWorld2
Return "Hello " + dataContractValue1.FirstName + " " + _
dataContractValue1.LastName
End Function 'HelloWorld2
End Class 'SimpleService
<DataContract()> _
Public Class DataContractType
Private _firstName As String
Private _lastName As String
<DataMember()> _
Public Property FirstName() As String
Get
Return _firstName
End Get
Set(ByVal value As String)
_firstName = value
End Set
End Property
<DataMember()> _
Public Property LastName() As String
Get
Return _lastName
End Get
Set(ByVal value As String)
_lastName = value
End Set
End Property
End Class 'DataContractType
End Namespace
using System;
using System.Web;
using System.Collections;
using System.Collections.Generic;
using System.Threading;
using System.Xml;
using System.Xml.Serialization;
using System.Text;
using System.IO;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.ServiceModel.Dispatcher;
using System.ServiceModel.Channels;
using System.ServiceModel.Activation;
// This a WCF service which consists of a contract,
// defined below as ISimpleService, and DataContractType,
// a class which implements that interface, see SimpleService,
// and configuration entries that specify behaviors associated with
// that implementation (see <system.serviceModel> in web.config)
namespace Aspnet.Samples
{
[ServiceContract()]
public interface ISimpleService
{
[OperationContract]
string HelloWorld1(string value1);
[OperationContract]
string HelloWorld2(DataContractType dataContractValue1);
}
[ServiceBehavior(IncludeExceptionDetailInFaults = true)]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class SimpleService : ISimpleService
{
public SimpleService()
{ }
public string HelloWorld1(string value1)
{
return "Hello " + value1;
}
public string HelloWorld2(DataContractType dataContractValue1)
{
return "Hello " + dataContractValue1.FirstName +
" " + dataContractValue1.LastName;
}
}
[DataContract]
public class DataContractType
{
string firstName;
string lastName;
[DataMember]
public string FirstName
{
get { return firstName; }
set { firstName = value; }
}
[DataMember]
public string LastName
{
get { return lastName; }
set { lastName = value; }
}
}
}
Vedere anche
Attività
Utilizzo del controllo UpdatePanel con un servizio Web
Concetti
Utilizzo dei servizi Web in ASP.NET AJAX
Utilizzo dei servizi Web in ASP.NET AJAX