公共静态双名称()的返回字符串

本文关键字：返回 字符串 静态 | 更新日期: 2023-09-27 18:27:59

我有richTextBox1，它从pingcheck（string，int）中获取结果，并且运行良好但有一件事我想添加它，当toaltime=0时，它在richTextBox1中显示"连接不可用"这是我的代码

public static double pingcheck(string host, int echonum) // i tried to change to (string host ,int echonum,string result) and add this string if total time =0 but its not retrieve it i tried to create public string but couldn't take string
    {
        long totaltime = 0;
        int timeout = 120;
     Ping pingsender = new Ping();//send ping
        for (int i = 0; i < echonum; i++)
        {
            PingReply replay = pingsender.Send(host, timeout);
            if (replay.Status == IPStatus.Success)
            {
            totaltime += replay.RoundtripTime;
            }
            else if(totaltime==0)
            {
         string getipstatue = "the connectin is not available ";//i want show this text in richTextBox if total time is=0
            }

        }
        return totaltime / echonum;        
    }
private void buttonX1_Click(object sender, EventArgs e)
    {
richTextBox1.Text += (pingcheck("8.8.8.",1))+Environment.NewLine; //this will show replay  
richTextBox2.Text += (pingcheck("8.8.1.",1))+Environment.NewLine;//i want this one get"the connection is not available pleas check" 
}

im使用windows窗体应用程序

公共静态双名称()的返回字符串

不能从类型为double的函数返回string。

问题的解决方案

检查零返回值有什么问题？

public static double PingCheck(string host, int echonum) 
{
    long totaltime = 0;
    int timeout = 120;
    Ping pingsender = new Ping();
    for (int i = 0; i < echonum; i++)
    {
        PingReply replay = pingsender.Send(host, timeout);
        if (replay.Status == IPStatus.Success)
        {
            totaltime += replay.RoundtripTime;
        } else {
            return 0.0;
        }
    }
    // at least, one of them should be double to avoid integer division
    return (double)totaltime / echonum; 
}
private void buttonX1_Click(object sender, EventArgs e)
{
    var pingCheckResult = PingCheck("8.8.8.", 1);
    richTextBox1.Text += pingCheckResult > 0 
        ? pingCheckResult.ToString("F2") + Environment.NewLine 
        : "the connectin is not available";
}

有很多其他方法可以做到这一点

  1. 例如，您可以使用out参数，并制作一个具有以下定义的方法：

    public static bool PingCheck(string host, int echonum, out double approximateTime) 
{
    long totaltime = 0;
    int timeout = 120;
    Ping pingsender = new Ping();
    for (int i = 0; i < echonum; i++)
    {
        PingReply replay = pingsender.Send(host, timeout);
        if (replay.Status == IPStatus.Success)
        {
            totaltime += replay.RoundtripTime;
        } 
        else 
        {
            approximateTime = 0.0;
            return false;
        }
    }
    // at least, one of them should be double to avoid integer division
    approximateTime = (double)totaltime / echonum;
    return true;
}
private void buttonX1_Click(object sender, EventArgs e)
{
    double appTime;
    if (PingCheck("8.8.8.", 1, out appTime))
    {
        richTextBox1.Text += appTime.ToString("F2") + Environment.NewLine;
    } else {
        richTextBox1.Text += "the connectin is not available";
    }
}

  2. 或者，您可以在PingCheck中抛出异常，然后在buttonX1_Click中捕获它。

  3. 或者，您实际上可以使您的方法返回string并执行以下操作：

    public static string PingCheck(string host, int echonum) 
{
    long totaltime = 0;
    int timeout = 120;
    Ping pingsender = new Ping();
    for (int i = 0; i < echonum; i++)
    {
        PingReply replay = pingsender.Send(host, timeout);
        if (replay.Status == IPStatus.Success)
        {
            totaltime += replay.RoundtripTime;
        } 
        else 
        {
            return "the connectin is not available";
        }
    }
    return (totaltime / echonum).ToString("F2");        
}

    然而，对我来说，就OOP而言，这似乎是不正确的。您的方法返回格式化的数字或错误消息。这很明显，也很不方便。

好吧，让我们做对吧。首先，任何方法都应该做自己的工作，在你的情况下，工作是计算ping主机的平均时间。pingcheck是什么意思？让我们更改名称：

  // 120 was a magic number, now it's a parameter
  // do you really want to pass attempts each time you call the method? No
  public static Double PingAverageTime(String host, int attempts = 3, int timeout = 120) {
    // Validate the input
    if (String.IsNullOrEmpty(host))
      throw new ArgumentNullError("host");
    else if (attempts <= 0)
      throw new ArgumentOutOfRangeError("attempts");
    else if (timeout < 0)
      throw new ArgumentOutOfRangeError("timeout");
    Double totalTime = 0; // Double: we don't want integer divison problems
    using (Ping ping = new Ping()) { // IDisposable - into using!
      PingReply replay = ping.Send(host, timeout);
      if (replay.Status == IPStatus.Success)
        totalTime += replay.RoundtripTime;
      else // not succeeded: so the time is infinite
        return Double.PositiveInfinity; // no connection - average time is infinite
    }
    return totalTime / attempts;
  }

然后使用方法：

  Double time = PingAverageTime("8.8.8.", 1);
  richTextBox1.Text += Double.IsInfinity(time) 
    ? "the connectin is not available " 
    : time.ToString();

将方法更改为：

public static string pingcheck(string host, int echonum) 
{
    ...
        else if(totaltime==0)
        {
            return "the connectin is not available ";//i want show this text in richTextBox if total time is=0
        }
    ...
    return (totaltime / echonum).ToString(); 
}
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