Question

我在尝试确定地址是IP地址还是主机名时遇到问题。我发现的一切都说使用正则表达式。我不知道如何形成IF声明。这是我的代码：

private void btnPingAddress_Click(object sender, EventArgs e)
{
    intByteSize = Convert.ToInt32(numericDataSize.Value);
    intNumberOfPings = Convert.ToInt32(numericPing.Value);
    strDnsAddress = cmbPingAddress.Text;
    //If address is IP address:
    if (strDnsAddress Contains ((2[0-4]\d|25[0-5]|[01]?\d\d?)\.){3}(2[0-4]\d|25[0-5]|[01]?\d\d?")
    {
       txtPingResults.Text = "Pinging " + strIpAddress + " with " + intByteSize + " bytes of data:" + "\r\n";
    }
    // If address is hostname:
    else
    {
       strIpAddress = Convert.ToString(Dns.GetHostEntry(strDnsAddress));
       txtPingResults.Text = "Pinging " + strDnsAddress + "  [" + strIpAddress + "]  with " + intByteSize + " bytes of data:" + "\r\n";
    }           
    Ping ping = new Ping();
    PingReply reply = ping.Send(cmbPingAddress.Text);
    txtPingResults.Text = "Pinging " + cmbPingAddress.Text + "  [" + Convert.ToString(reply.Address) + "]  with " + intByteSize + " bytes of data:" + "\r\n";
    for (int i = 0; i < intNumberOfPings; i++)
    {
       txtPingResults.AppendText("Reply from "+Convert.ToString(reply.Address)+": Bytes="+Convert.ToString(intByteSize) +" Time="+Convert.ToString(reply.RoundtripTime) +"ms"+" TTL="+Convert.ToString(reply.Options.Ttl)+ "\r\n");
       cmbPingAddress.Items.Add(cmbPingAddress.Text);
    }
}

非常感谢任何帮助。

Answer 1

我最近需要这样做以拆分WebAPI标头。 Uri.CheckHostName可能是最简单的方法，它包括ipv6支持：

var dns = Uri.CheckHostName("www.google.com"); //UriHostNameType.Dns
var ipv4 = Uri.CheckHostName("192.168.0.1");   //IPv4
var ipv6 = Uri.CheckHostName("2601:18f:780:308:d96d:6088:6f40:c5a8");//IPv6
dns = Uri.CheckHostName("Foo");    //Dns

最后一个很棘手，但在技术上是正确的。至少，您可以排除主机名与IP地址。

Answer 2

尝试：

ValidIpAddressRegex = "^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$";

ValidHostnameRegex = "^(([a-zA-Z]|[a-zA-Z][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z]|[A-Za-z][A-Za-z0-9\-]*[A-Za-z0-9])$";



if(Regex.IsMatch(strDnsAddress, ValidIpAddressRegex )) {
    // the string is an IP
}
else if(Regex.IsMatch(strDnsAddress,ValidHostnameRegex )){
    // the string is a host

 }

Answer 3

使用你的正则表达式：

if(Regex.IsMatch(strDnsAddress, "(2[0-4]\d|25[0-5]|[01]?\d\d?)\.){3}(2[0-4]\d|25[0-5]|[01]?\d\d?")) {
    // the string is an IP
}

或者你可以使用this问题中提供的正则表达式（正如habib zare在他的评论中所建议的那样）

Answer 4

我试图以一种非常基本且易于理解的初学者来解释这个概念！

注意：：函数的参数定义为可选参数（CheckHost(string host="127.0.0.0")）

public static void CheckHost(string host="127.0.0.1")
    {
        if (host == null || host.Length == 0)
        {
            Console.WriteLine("no host is defined!");
        }
        else if (Uri.CheckHostName(host).ToString() == "Dns")
        {
            Console.WriteLine("The "+host+" is a DNS hostname.");

        }
        else if (Uri.CheckHostName(host).ToString() == "IPv4")
        {
            Console.WriteLine("The " + host + " is an IP Address v4.");
        }
        else if (Uri.CheckHostName(host).ToString() == "IPv6")
        {
            Console.WriteLine("The " + host + " is an IP Address v6.");
        }
        else
        {
            Console.WriteLine("The " + host + " is unknown!");
        }
    }

确定组合框文本是IP地址还是主机名

4 个答案: