C# 更改静态void GetResponseCallback中的表单标签

嗨，我尝试更改标签元素，但文本没有更改

       public partial class Form1 : Form
        {       
            public Form1()
            {
                InitializeComponent();
            }

           private void button1_Click(object sender, EventArgs e)
            {
                sendPOST("http://example");            
            }

            public static void sendPOST(string URL)
            {
                // Create a request using a URL that can receive a post. 
                HttpWebRequest request = (HttpWebRequest) WebRequest.Create(URL);
                // Set the ContentType property of the WebRequest.
                request.ContentType = "application/x-www-form-urlencoded";

                // Set the Method property of the request to POST.
                request.Method = "POST";

                // start the asynchronous operation
                request.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback),request);

                allDone.WaitOne();        
            }

private static void GetRequestStreamCallback(IAsyncResult asynchronousResult)
        {

            HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;

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

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

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

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

    private static void GetResponseCallback(IAsyncResult asynchronousResult)
           {
              //.....
              Form1 test = new Form1();
              test.statusLabel.Text  = responseString; //dont write anything

               Console.WriteLine(responseString); //works well
              //.....
        }

我怎样才能改变它

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更新：添加更多代码。我如何获得现有的Form1实例来更新Form1 LabelField，以便在asyn完成后显示一些内容？

从对问题的评论中，我想您可以这样做：将要更改的表单实例作为用户定义的对象

状态

传递给导致调用

GetResponseCallback

的调用（大多数

BeginXYZ

方法允许您传递用户定义的对象，该对象随后处于

IAsyncResult.State

）中。然后您可以执行以下操作：

Form1 test = asynchronousResult.State as Form1;
test.StatusLabel.Text = responseString;

test.Invoke((Action)delegate() { StatusLabel.Text = responseString; });

请注意，由于多线程问题，可能不允许您更改

文本

属性，并且必须使用

控件。调用

来执行此操作。上有许多线程描述了这一点

我现在没有可用的代码示例，但如果我没有弄错的话，它应该是这样的：

Form1 test = asynchronousResult.State as Form1;
test.StatusLabel.Text = responseString;

test.Invoke((Action)delegate() { StatusLabel.Text = responseString; });

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如何从静态GetResponseCallback访问现有的Form1实例？@Servy，更新代码，请查看。谢谢。我终于将代码更改为使用更新主UI的线程。BeginInvoke（）一次又一次地抛出此命令…请投票人解释他为什么要投票！？