Question

我正在学习c＃并尝试了我在stackoverflow上找到的其他解决方案..但我失败了..

我在点击按钮时尝试检查网址是否存在。

单击该按钮时，progressBar将设置为选取框并开始验证。

但系统会停止，直到结果退回..

这是按钮点击：

private void button1_Click(object sender, EventArgs e)
{

   this.progressBar1.Style = System.Windows.Forms.ProgressBarStyle.Marquee;

   if (RemoteFileExists("http://www.gofdisodfi.com/"))
   {
      // OK
   }
   else
   {
      //FAIL
   }
}

这是支票：

private bool RemoteFileExists(string url)
{
   try
   {
      HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
      request.Method = "HEAD";
      HttpWebResponse response = request.GetResponse() as HttpWebResponse;
      return (response.StatusCode == HttpStatusCode.OK);
   }
   catch
   {
      return false;
   }
}

Answer 1

您可以使用＆＃34; async并等待＆＃34;异步操作的语法。它不会冻结UI

private async void button1_Click(object sender, EventArgs e)
    {
        this.progressBar1.Style = System.Windows.Forms.ProgressBarStyle.Marquee;

        var result = await RemoteFileExists("http://www.google.com/");

        if (result)
        {
            // OK
            MessageBox.Show("OK");
        }
        else
        {
            //FAIL
            MessageBox.Show("Fail");
        }
    }

    private async Task<bool> RemoteFileExists(string url)
    {
        try
        {
            HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
            request.Method = "HEAD";
            HttpWebResponse response = await request.GetResponseAsync() as HttpWebResponse;
            return (response.StatusCode == HttpStatusCode.OK);
        }
        catch
        {
            return false;
        }
    }

您可以在此处详细了解：http://blog.stephencleary.com/2012/02/async-and-await.html

为什么UI在长时间运行期间冻结

1 个答案: