Sys.Net.WebRequest总结

关于asp.net AJAX还会有很多。

Sys.Net.WebRequest

提供客户端Script功能制造一个Web请求.

Constructors

Sys.Net.WebRequest webRequest Constructor

初始画一个新的WebRequest class的实例.
var wRequest = new Sys.Net.WebRequest();

Members

(1)Sys.Net.WebRequest add_completed Method
结合Web请求实例注册一个事件,

wRequest.add_completed(handler);

(2)Sys.Net.WebRequest completed Method
结合Sys.Net.WebRequest事例添加完整的事件.

(3)Sys.Net.WebRequest.getResolvedUrl Method
得到一个Web请求实例的resolved URL

(4)Sys.Net.WebRequest invoke Method
执行Web请求
Sys.Net.WebRequestManager.invoke(WebRequest);
异常:
Sys.InvalidOperationException        最多只能调用一次

如果你已经注册completed request event handler为你的Sys.Net.WebRequest 实例,按照网络堆异步调用 handler的请求过程.一个WebRequest实例中只能调用一个invoke.如果网络请求已经发出就会抛出一个异常.

(5)Sys.Net.WebRequest remove_completed Method
删除添加在Handler上的add_completed方法.
返回值必须是字符串,null,或一个XmlDocument对象实例.

(6)Sys.Net.WebRequest executor Property
得到,设置结合Sys.Net.WebRequest实例的执行者

(7)Sys.Net.WebRequest body Property
得到,设置一个Sys.Net.WebRequest实例的HTTP body.
只是在我们要自定义网络执行者的时候才使用.如果你不设置这个属性,
系统默认为Sys.Net.XmlHttpExecutor执行者,设置在调用invoke之后.
如果你的WebRequest实例已经与执行关联并且Web request已经发行.
如果你尝试设置executor属性,就像这样
myRequest.set_executor(myRequest.get_executor())
就会有一个异常被抛出.

var body = MyWebRequest.get_body();

MyWebRequest.set_body(value);

(8)Sys.Net.WebRequest headers Property
为Sys.Net.WebRequest实例得到HTTP headers,WebRequest发送的
HTTP headers是键值对的字典.headers属性返回为一个字典.
如果没有自定义headers,返回这个字典为空.你使用返回字典来设置你的自定义header 值.

(9)Sys.Net.WebRequest httpVerb Property
得到或设置一个使用Sys.Net.WebRequest类的HTTP verb.

注意,如果之前Http verb没有被设定.那就要在如果body属性为null,
WebRequest返回"GET",如果body属性为null,
WebRequest返回"POST".如果返回body是一个空字符串(""),
但其实不是null,返回的也应该是"POST"

(10)Sys.Net.WebRequest timeout Property
设置或得到Sys.Net.WebRequest实例超时值.当去前的超时值是以毫秒值.
这个超时属性是表示在结合WebRequest实例网络执行者等待网络请求之前的超时时间.
"0"表示下一个网络堆立即输出.

(11)Sys.Net.WebRequest url Property
得到或设置Sys.Net.WebRequest实例的URL.如果URL没被设置,返回值为空字符串("").
你能设置一个完整的URL,一个绝对的URL,或相对的URL.
WebRequest能将这个值转换给network执行者使用.

(12)Sys.Net.WebRequest userContext Property
得到或设置用户context.返回user context,userContext属性要在WebRequest调用invoke方法之前调用.
Web请求的completed handler能使用相同的userContext.
允许区别不同的事件handler调用者,或重新获得状态或当处理返回数据的context.

WebRequest类被使用在异步交流层中,制造一个Web请求.在你的应用程序中不用刻意使用这个类,而是在你需要在浏览器中调用Web service方法或静态页面方法按照使用代理方法时使用.

你能创建和使用一个WebRequest实例在下面场景中使用:

    当你要制造网络请求不是简单的Web service方法调用(就是这是一种复杂的调用Web service的方法).
    当你要设置HTTP请求属性.
    当你使用自定义的执行者,要基于Sys.Net.WebRequestExecutor类.

下面是事例来于MSDN:

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html >

<title> Using WebRequest </title>

body { font: 11pt Trebuchet MS;

font-color: #000000;

padding-top: 72px;

text-align: center }

.text { font: 8pt Trebuchet MS }

</style>

</head>

<body>

<h2>Using WebRequest</h2>

<asp:ScriptManager runat="server" ID="ScriptManagerId">

<asp:ScriptReference Path="WebRequest.js" />

</Scripts>

</asp:ScriptManager>

</form>

<table>

<td>Make GET Request:</td>

<td>

<button id="Button1"

onclick="GetWebRequest()">GET</button>

</td>

</tr>

<td>Request Body:</td>

<td>

<button id="Button2"

onclick="PostWebRequest()">Body</button>

</td>

</tr>

<td>Request Timeout:</td>

<td>

<button id="Button3"

onclick="WebRequestTimeout()">Timeout</button>

</td>

</tr>

<td>Request Completed Handler:</td>

<td>

<button id="Button4"

onclick="WebRequestCompleted()">Completed Handler</button>

</td>

</tr>

<td>Resolved Url:</td>

<td>

<button id="Button5"

onclick="GetWebRequestResolvedUrl()">Resolved Url</button>

</td>

</tr>

<td>Request Executor:</td>

<td>

<button id="Button6"

onclick="WebRequestExecutor()">Executor</button>

</td>

</tr>

<td>Request Header:</td>

<td>

<button id="Button7"

onclick="WebRequestHeader()">Header</button>

</td>

</tr>

</table>

<hr />

</body>

</html>

var getPage;

var postPage;

var displayElement;

function pageLoad()

{

getPage = "getTarget.htm";

postPage = "postTarget.aspx";

displayElement = $get("ResultId");

}

// This function performs a GET Web request

// to retrieve information from the Url specified in

// the query string.

function GetWebRequest()

{

alert("Performing Get Web request.");

// Instantiate the WebRequest object.

var wRequest = new Sys.Net.WebRequest();

// Set the request Url.

wRequest.set_url(getPage);

// Set the request verb.

wRequest.set_httpVerb("GET");

// Set user's context

wRequest.set_userContext("user's context");

// Set the web request completed event handler,

// for processing return data.

wRequest.add_completed(OnWebRequestCompleted);

// Clear the results page element.

displayElement.innerHTML = "";

// Execute the request.

wRequest.invoke();

}

// This function performs a POST Web request

// to upload information to the resource

// identified by the Url.

function PostWebRequest()

{

// Instantiate the WebRequest object.

var wRequest = new Sys.Net.WebRequest();

// Set the request Url.

wRequest.set_url(postPage);

// Set the request verb.

wRequest.set_httpVerb("POST");

var body = "Message=Hello! Do you hear me?"

wRequest.set_body(body);

wRequest.get_headers()["Content-Length"] = body.length;

// Set the web request completed event handler,

// for processing return data.

wRequest.add_completed(OnWebRequestCompleted);

// Clear the results page element.

displayElement.innerHTML = "";

// Execute the request.

wRequest.invoke();

}

// This function adds and removes the

// Web request completed event handler.

function WebRequestCompleted()

{

// Instantiate the WebRequest.

var wRequest = new Sys.Net.WebRequest();

// Set the request Url.

wRequest.set_url(getPage);

// Set the web request completed event handler,

// for processing return data.

wRequest.add_completed(OnWebRequestCompleted);

alert("Added Web request completed handler");

// Remove the web request completed event handler.

// Comment the following two lines if you want to

// use the handler.

wRequest.remove_completed(OnWebRequestCompleted);

alert("Removed handler; the Web request return is not processed.");

// Execute the request.

wRequest.invoke();

}

// This function gets the resolved Url

// of the Web request instance.

function GetWebRequestResolvedUrl()

{

// Instantiate the WebRequest.

var wRequest = new Sys.Net.WebRequest();

// Set the request Url.

wRequest.set_url(getPage);

// Get the web request completed event handler.

var resUrl = wRequest.getResolvedUrl();

alert("Resolved Url: " + resUrl);

// Set the web request completed event handler,

// for processing return data.

wRequest.add_completed(OnWebRequestCompleted);

// Execute the request.

wRequest.invoke();

}

// This function gets and sets the

// Web request time out.

function WebRequestTimeout()

{

// Instantiate the WebRequest.

var wRequest = new Sys.Net.WebRequest();

// Set the request Url.

wRequest.set_url(getPage);

var defaultTimeout =

wRequest.get_timeout();

// Set request timeout to 100 msec.

wRequest.set_timeout(100);

var newTimeout =

wRequest.get_timeout();

alert("Default timeout: " + defaultTimeout);

alert("New timeout: " + newTimeout);

// Set the web request completed event handler,

// for processing return data.

wRequest.add_completed(OnWebRequestCompleted);

// Execute the request.

wRequest.invoke();

}

// This function sets the Web request

// executor, replacing the default one.

function WebRequestExecutor()

{

// Instantiate the WebRequest.

var wRequest = new Sys.Net.WebRequest();

// Create the executor. In this case it is an

// XMLHttpExecutor, equivalent to the default

// executor. But, you can create a custom one.

var executor = new Sys.Net.XMLHttpExecutor();

// Set the executor, replacing the default one.

// In this case the executor is equivalent to the

// default one.

wRequest.set_executor(executor);

// Get the current executor

var executor =

wRequest.get_executor();

alert("Response availabe: " + executor.get_responseAvailable())

}

// This function sets an HTTP header for

// the Web request.

function WebRequestHeader()

{

// Instantiate the WebRequest object.

var wRequest = new Sys.Net.WebRequest();

// Set the request Url.

wRequest.set_url(postPage);

// Set the request verb.

wRequest.set_httpVerb("POST");

var body = "Message=Hello! Do you hear me?"

wRequest.set_body(body);

// Set the value of the HTTP header's "Content-Length".

wRequest.get_headers()["Content-Length"] = body.length;

// Set the web request completed event handler,

// for processing return data.

wRequest.add_completed(OnWebRequestCompletedHeader);

// Clear the results page element.

displayElement.innerHTML = "";

// Execute the request.

wRequest.invoke();

}

// This the handler for the Web request completed event

// that is used to display return data.

function OnWebRequestCompleted(executor, eventArgs)

{

if(executor.get_responseAvailable())

{

// Clear the previous results.

displayElement.innerHTML = "";

// Display Web request status.

DisplayWebRequestStatus(executor);

// Display Web request headers.

DisplayWebRequestHeaders(executor);

// Display Web request body.

DisplayWebRequestBody(executor);

}

else

{

if (executor.get_timedOut())

alert("Timed Out");

else

if (executor.get_aborted())

alert("Aborted");

}

// This the handler for the Web request completed event

// that is used to display header information.

function OnWebRequestCompletedHeader(executor, eventArgs)

{

if(executor.get_responseAvailable())

{

// Clear the previous results.

displayElement.innerHTML = "";

// Display Web request headers.

DisplayWebRequestHeaders(executor);

}

else

{

if (executor.get_timedOut())

alert("Timed Out");

else

if (executor.get_aborted())

alert("Aborted");

}

// This function is used to display the Web request status.

function DisplayWebRequestStatus(executor)

{

displayElement.innerHTML +=

"Status: [" +

executor.get_statusCode() + " " +

executor.get_statusText() + "]" + "<br/>"

}

// This function is used to display Web request HTTP headers.

function DisplayWebRequestHeaders(executor)

{

displayElement.innerHTML +=

"Headers: ";

displayElement.innerHTML +=

executor.getAllResponseHeaders() + "<br/>";

}

// This function is used to display the Web request body.

function DisplayWebRequestBody(executor)

{

displayElement.innerHTML +=

"Body: ";

if (document.all)

displayElement.innerText +=

executor.get_responseData();

else

// Firefox

displayElement.textContent +=

executor.get_responseData();

}

// This function is used to display the Web request message.

function DisplayInformation(message)

{

// Clear the previous results.

displayElement.innerHTML = "";

// Display information.

displayElement.innerHTML = "<br/>" + message;

}

if (typeof(Sys) !== "undefined") Sys.Application.notifyScriptLoaded();

可能上面的着个实例有一点复杂..但是一个很好的实力。

posted @ 2008-03-10 21:43 works guo 阅读(3058) 评论(3) 收藏举报

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