C# 如何在不等待其他操作完成的情况下更新视图

假设我有一个带有多个标签的GroupBox。在这些标签中，将显示各种与IP相关的信息。一个信息是机器的外部IP地址

string externalIP = "";

try
{
    WebRequest request = WebRequest.Create("http://checkip.dyndns.org/");
    request.Timeout = 3000;
    System.Threading.Tasks.Task<System.Net.WebResponse> response =  request.GetResponseAsync();

    using (StreamReader stream = new StreamReader(response.Result.GetResponseStream()))
    {
        if (response.Result.ContentLength != -1)
        {
             externalIP = stream.ReadToEnd();
        }
    }               
}
catch (Exception e)
{
    externalIP = "Error.";
}

if (externalIP == "")
{
    return "No service.";
}
else
{
    return externalIP = (new Regex(@"\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}")).Matches(externalIP)[0].ToString();
}

---

在getExternalIPv4（）之后如何执行代码，即使它尚未完成？它可以在设置超时时工作，就像我上面所做的那样，但有时请求只需要稍长的时间，但仍然成功完成。因此，我希望仍然能够显示外部IP，但继续执行刷新GroupBox的其他方法。

BackgroundWorker将提供您所需要的。示例代码：

BackgroundWorker bg = new BackgroundWorker();
bg.DoWork += new DoWorkEventHandler(getExternalIPv4Back);
bg.RunWorkerCompleted += new RunWorkerCompletedEventHandler(writeLabel);
bg.RunWorkerAsync();
//The code below this point will be executed while the BackgroundWorker does its work

您必须将

getExternalIPv4Back

定义为

DoWork事件方法

，并在其中包含要并行执行的代码；另外，

writeLabel

作为

RunWorkerCompleted事件（编辑标签而不引发多线程相关错误时需要）。即:

private void getExternalIPv4Back(object sender, DoWorkEventArgs e)
{
    IP = "External IPv4: " + getExternalIPv4(); //IP -> Globally defined variable
}

private void writeLabel(object sender, RunWorkerCompletedEventArgs e)
{
   lblIP4external.Text = IP;
}

private void getExternalIPv4Back(object sender, DoWorkEventArgs e)
{
    IP = "External IPv4: " + getExternalIPv4(); //IP -> Globally defined variable
}

private void writeLabel(object sender, RunWorkerCompletedEventArgs e)
{
   lblIP4external.Text = IP;
}