將變量推入方法

我有一個httpWebRequest來訪問XML並將其保存到本地，然後將其讀取並顯示到屏幕上。問題是，我有一個以上的「樞紐項目」做到這一點，而且節省了XML的方法是將變量推入方法

private static void GetResponseCallback(IAsyncResult asynchronousResult)

，不支持增加一個新的變量，所以我可以動態命名XML （「tmp」+ xmlName +「。xml」）。

所以問題是：我如何推送一個變量在XML名稱？

public class HttpWebReqMethod 
    { 

     public void httpRequestMethod (string url, string xmlName) 
     {  
      HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create(url); 
      httpRequest.ContentType = "text/xml"; 
      httpRequest.Method = "POST"; 

      httpRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), httpRequest); 
     } 

     private static void GetRequestStreamCallback(IAsyncResult asynchronousResult) 
     { 
      HttpWebRequest httpRequest = (HttpWebRequest)asynchronousResult.AsyncState; 

      // End the operation 
      Stream postStream = httpRequest.EndGetRequestStream(asynchronousResult); 


      string postData = ""; 

      // Convert the string into a byte array. 
      byte[] byteArray = Encoding.UTF8.GetBytes(postData); 

      // Write to the request stream. 
      postStream.Write(byteArray, 0, postData.Length); 
      postStream.Close(); 

      // Start the asynchronous operation to get the response 
      httpRequest.BeginGetResponse(new AsyncCallback(GetResponseCallback), httpRequest); 
     } 

     private static void GetResponseCallback(IAsyncResult asynchronousResult) 
     { 
      HttpWebRequest httpRequest = (HttpWebRequest)asynchronousResult.AsyncState; 

      // End the operation 
      HttpWebResponse response = (HttpWebResponse)httpRequest.EndGetResponse(asynchronousResult); 
      Stream streamResponse = response.GetResponseStream(); 
      StreamReader streamRead = new StreamReader(streamResponse); 
      string responseStream = streamRead.ReadToEnd(); 

      using (var store = IsolatedStorageFile.GetUserStoreForApplication()) 
      { 
       using (var istream = new IsolatedStorageFileStream(@"tmp" + xmlName + ".xml", FileMode.OpenOrCreate, store)) 
       { 
        using (var sw = new StreamWriter(istream)) 
        { 
         sw.Write(responseStream); 
        } 
       } 
      } 

      // Close the stream object 
      streamResponse.Close(); 
      streamRead.Close(); 

      // Release the HttpWebResponse 
      response.Close(); 
     }

來源

2012-05-28 observ

這裏有兩個事情可以做：

使GetResponseCallback不是靜態的，儲存在一個實例變量
的xmlName傳遞狀態對象（任何有一個名爲xmlName的屬性，以及其他用來標識它的內容），並且您可以從AsyncState

變化GetResponseCallback的功能，下面，使整個事情的回調「工廠」

private static AsyncCallback GetResponseCallback(string xmlName) 
{ 
    return (IAsyncResult asynchronousResult) =>{ 
    HttpWebRequest httpRequest = (HttpWebRequest)asynchronousResult.AsyncState; 
    // End the operation 
    HttpWebResponse response = (HttpWebResponse)httpRequest.EndGetResponse(asynchronousResult); 
    Stream streamResponse = response.GetResponseStream(); 
    StreamReader streamRead = new StreamReader(streamResponse); 
    string responseStream = streamRead.ReadToEnd(); 

    using (var store = IsolatedStorageFile.GetUserStoreForApplication()) 
    { 
     using (var istream = new IsolatedStorageFileStream(@"tmp" + xmlName + ".xml", FileMode.OpenOrCreate, store)) 
     { 
      using (var sw = new StreamWriter(istream)) 
      { 
       sw.Write(responseStream); 
      } 
     } 
    } 

    // Close the stream object 
    streamResponse.Close(); 
    streamRead.Close(); 

    // Release the HttpWebResponse 
    response.Close(); 
    } 
}

編輯補充：
使用則變爲

httpRequest.BeginGetRequestStream(GetRequestStreamCallback(xmlName), httpRequest);

來源

2012-05-28 20:23:37 TDaver

哦，我看到rudi_visser選擇了第二個選項，並解釋它更好的:)還有第三個是一個很好的和對於某些場景可能非常有用。 – TDaver

你能幫我打回「工廠」嗎？我得到：GetResponseCallback（字符串）'返回void，一個返回關鍵字不能跟在一個對象表達式 – observ

請注意，我已經更改了SIGNATURE ... – TDaver

它一個映射到特定委託類型的回調方法，所以不能，你不能修改它的簽名。解決這個

一種選擇是將有一個單獨的類像這樣：

class HttpRequestState { 
    HttpWebRequest httpWebRequest; 
    string xmlFileName; 
}

然後，您可以設置類作爲狀態對象的實例在運行開始回調：

httpRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), httpRequest);

將變爲

httpRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), new HttpRequestState() { httpWebRequest = httpRequest; xmlFileName = "tmp"+xmlName+".xml" });

然後，當然，你可以拉出來的xmlFileName 和的HttpWebRequest的是這樣的：

HttpRequestState stateObj = (HttpRequestState)asynchronousResult.AsyncState; 
HttpWebRequest httpRequest = stateObj.httpWebRequest; 
string fileName = xmlFileName;

來源

2012-05-28 20:24:17

將變量推入方法

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