C# 将变量推入方法

我有一个httpWebRequest来访问XML并将其保存在本地，然后读取它并将其显示在屏幕上。问题是，我必须为多个“透视项”执行此操作，而保存xml的方法是

private static void GetResponseCallback(IAsyncResult asynchronousResult)

并且不支持向其添加新变量，以便动态命名xml（“tmp”+xmlName+“.xml”）

所以问题是：如何在xml名称中推送变量？

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();
        }

---

以下是您可以做的两件事：

使GetResponseCallback不是静态的，并将xmlName存储在实例变量中

将一个状态对象（任何具有名为xmlName的属性的对象，以及用于标识它的其他对象）传递给请求，您可以从

异步状态

将GetResponseCallback的函数更改为以下内容，并将整件事设置为回调“工厂”

编辑以添加：
然后，用法更改为

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

---

它是一个映射到特定委托类型的回调方法，因此不，您不能修改它的签名

解决此问题的一个选项是使用一个单独的类，例如：

class HttpRequestState {
    HttpWebRequest httpWebRequest;
    string xmlFileName;
}

然后，可以在运行Begin回调时将该类的实例设置为状态对象：

httpRequest.BeginGetRequestStream（新的异步回调（GetRequestStreamCallback），httpRequest）

将更改为

httpRequest.BeginGetRequestStream（新的AsyncCallback（GetRequestStreamCallback），新的HttpRequestState（）{httpWebRequest=httpRequest；xmlFileName=“tmp”+xmlName+“.xml”}）

当然，您可以像这样取出xmlFileName和httpWebRequest：

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

哦，我知道鲁迪欧·维瑟选择了第二个选项，并且解释得更好：）第三个选项仍然很好，在某些情况下非常有用。你能帮我找到“回调”工厂吗？我得到：GetResponseCallback（string）'返回void，return关键字后面不能跟有响应的对象表达式。我只需要稍微清醒一下：）
HttpRequestState stateObj = (HttpRequestState)asynchronousResult.AsyncState;
HttpWebRequest httpRequest = stateObj.httpWebRequest;
string fileName = xmlFileName;