在标签文本中显示Ping.SendAsync的结果

Question

我正在尝试创建一个简单的ping程序GUI实现。我有一个表单，它只是一个文本框textBox1，用户输入IP作为字符串，按下按钮Ping，ping的结果显示在标签label1中。出于某种原因，运行程序时文本不会显示。从Ping.SEndAsync部分采取

代码：

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
using System.Windows.Forms; 
using System.IO; 
using System.Threading; 
using System.Net.NetworkInformation; 
using System.Net; 

namespace pinger 
{ 
    public partial class Form1 : Form 
    { 
     private string address; 
     private string response; 
     private PingReply reply; 
     //public string response; 

     private void PingCompletedCallback(object sender, PingCompletedEventArgs e) 
     { 
      if (e.Cancelled) 
       ((AutoResetEvent)e.UserState).Set(); 
      if (e.Error != null) 
       ((AutoResetEvent)e.UserState).Set(); 
      reply = e.Reply; 
      ((AutoResetEvent)e.UserState).Set(); 

      if (reply == null) 
       return; 
     } 

     public Form1() 
     { 
      InitializeComponent(); 
     } 

     private void Form1_Load(object sender, EventArgs e) 
     { 

     } 

     private void textBox1_TextChanged(object sender, EventArgs e) 
     { 
      address = IPtextbox.Text; 
     } 

     private void Ping_click(object sender, EventArgs e) 
     { 
      AutoResetEvent waiter = new AutoResetEvent(false); 

      Ping pingSender = new Ping(); //creates a new 'pingSender' Ping object 

      pingSender.PingCompleted += 
       new PingCompletedEventHandler(PingCompletedCallback); 

      // Create a buffer of 32 bytes of data to be transmitted. 
      string data = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"; 
      byte[] buffer = Encoding.ASCII.GetBytes(data); 

      int timeout = 1000; 
      pingSender.SendAsync(address, timeout, buffer, waiter); 
     } 

     private void label1_Click(object sender, EventArgs e) 
     { 
      label1.Text = "the ping was: " + reply.Status.ToString(); 
      Show(); 
      Refresh(); 
     } 
    } 
} 

Answer 1

根据你的代码中仅标注当你点击它改变它的文本。 label1_Click事件引发。

PingCompleted事件以获取有关完成状态的信息和通过调用SendAsync方法收集的数据。在其中，您可以使用ping的结果更改标签文本。

将label1_Click中的所有代码添加到PingCompletedCallback方法如下;

private void PingCompletedCallback(object sender, PingCompletedEventArgs e) 
    { 
     if (e.Cancelled || e.Error != null) 
      ((AutoResetEvent)e.UserState).Set(); 

     reply = e.Reply;    

     if (reply == null) 
      return; 

     //Change the label here 
     label1.Text = "the ping was: " + reply.Status.ToString(); 
     Show(); 
     Refresh(); 
    }