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 > <head id="Head1" runat="server"> <title> Using WebRequest </title> <style type="text/css">
body { font: 11pt Trebuchet MS;
body 
font-color: #000000; padding-top: 72px;
text-align: center } .text { font: 8pt Trebuchet MS }
</style> </head> <body> <h2>Using WebRequest</h2> <form id="form1" runat="server"> <asp:ScriptManager runat="server" ID="ScriptManagerId"> <Scripts> <asp:ScriptReference Path="WebRequest.js" /> </Scripts> </asp:ScriptManager> </form> <table> <tr align="left"> <td>Make GET Request:</td> <td> <button id="Button1" onclick="GetWebRequest()">GET</button> </td> </tr> <tr align="left"> <td>Request Body:</td> <td> <button id="Button2" onclick="PostWebRequest()">Body</button> </td> </tr> <tr align="left"> <td>Request Timeout:</td> <td> <button id="Button3" onclick="WebRequestTimeout()">Timeout</button> </td> </tr> <tr align="left"> <td>Request Completed Handler:</td> <td> <button id="Button4" onclick="WebRequestCompleted()">Completed Handler</button> </td> </tr> <tr align="left"> <td>Resolved Url:</td> <td> <button id="Button5" onclick="GetWebRequestResolvedUrl()">Resolved Url</button> </td> </tr> <tr align="left"> <td>Request Executor:</td> <td> <button id="Button6" onclick="WebRequestExecutor()">Executor</button> </td> </tr> <tr align="left"> <td>Request Header:</td> <td> <button id="Button7" onclick="WebRequestHeader()">Header</button> </td> </tr> </table> <hr /> <div id="ResultId" style="background-color:Aqua;"></div> </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();