用c#语言怎么判断IP地址是否有效？

一ipv4为例，简单的思路是获取文本框的字符串，然后以“.”将字符串分离为含有四个元素的字符串数组。判断每一个元素对应的值是否在0到255之间。
参考代码：
        //判断IP地址是否有效
        public static bool IsRightIP(string ip)
        {
            if (Regex.IsMatch(ip, "[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}"))
            {
                string[] ips = ip.Split('.');
                if (ips.Length == 4 || ips.Length == 6)
                {
                    if (System.Int32.Parse(ips[0]) < 256 && System.Int32.Parse(ips[1]) < 256 & System.Int32.Parse(ips[2]) < 256 & System.Int32.Parse(ips[3]) < 256)
                        return true;
                    else
                        return false;
                }
                else
                    return false;
            }
            else
                return false;
        }

1楼的方法有点搞笑，既然用了正则，那就一个正则搞定就是了，何必还要再拆分判断C#中提供了IPAddress类，可以直接判断
IPAddress ip;
if (IPAddress.TryParse(textBox1.Text, out ip))
{
MessageBox.Show("合法！");
}
else
{
MessageBox.Show("不合法！");
}

上面的只是合法性检查，至于有效性检查，Ping一下吧

楼上的那个正则表达式，
我有个特例：
127.1你试试ping这个地址，可以正常解析成本机的。
可是不能通过你的正则表达式。

ctrl+.
在没有名字空间的类上面按。

增加命名空间
using System.Text.RegularExpressions;

直接用IPAddress类。很方便就可以做到。

有效性不等于合法性。还是要ping 吧。

问题是那个类怎么调用呀，它提示错误 1 找不到类型或命名空间名称“IPAddress”(是否缺少 using 指令或程序集引用?) 2 当前上下文中不存在名称“IPAddress” F

我知道了，是要引用useing System.Net; 但是我觉得这种方法判断有个问题，就是我随便输入一个数比如123 它都判断合法~~~~晕

123 会被认为是 0.0.0.123如果想严格限定格式，用正则判断吧using System.Text.RegularExpressions;Regex reg = new Regex(@"(?n)^(([1-9]?[0-9]|1[0-9]{2}|2([0-4][0-9]|5[0-5]))\.){3}([1-9]?[0-9]|1[0-9]{2}|2([0-4][0-9]|5[0-5]))$");
if (reg.IsMatch(textBox1.Text))
{
MessageBox.Show("合法！");
}
else
{
MessageBox.Show("不合法！");
}

public static bool Validate(string IP)
{
if (string.IsNullOrEmpty(IP))
return false; return Regex.IsMatch(IP, @"^((\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.){3}(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$");
}

发你一套操作IP的类using System;
using System.Text;
using System.Text.RegularExpressions;
using HKH.Common;namespace HKH.Common.Network
{
/// <summary>
///
/// </summary>
/// <res> immutable class </res>
public class IPAddress : INullable
{
protected const int IPLENGTH = 4;
protected byte[] parts = new byte[4]; public IPAddress(byte p1, byte p2, byte p3, byte p4)
{
parts[0] = p1;
parts[1] = p2;
parts[2] = p3;
parts[3] = p4;
} public IPAddress(byte[] ip)
:this(ip[0],ip[1],ip[2],ip[3])
{
} public static IPAddress Null
{
get { return NullIPAddress.Instance; }
} public static bool Validate(string IP)
{
if (string.IsNullOrEmpty(IP))
return false; return Regex.IsMatch(IP, @"^((\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.){3}(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$");
} public static byte[] Split(string sIP)
{
if (!Validate(sIP))
throw new IPBadFormatException(); byte[] ip = new byte[IPLENGTH];
string[] sParts = sIP.Split('.'); for (int i = 0; i < IPLENGTH; i++)
ip[i] = byte.Parse(sParts[i]); return ip;
} public virtual uint TransferToUINT()
{
return MakeLong(MakeWord(parts[3], parts[2]), MakeWord(parts[1], parts[0]));
} public virtual int Compare(IPAddress IP)
{
return (int)(this.TransferToUINT() - IP.TransferToUINT());
} #region Protected Methods protected static ushort MakeWord(byte bLow, byte bHigh)
{
return ((ushort)(((byte)(bLow)) | ((ushort)((byte)(bHigh))) << 8));
} protected static uint MakeLong(ushort bLow, ushort bHigh)
{
return ((uint)(((ushort)(bLow)) | ((uint)((ushort)(bHigh))) << 16));
} #endregion #region Base Overrides public override bool Equals(object obj)
{
if (obj == null)
return false; IPAddress ip = obj as IPAddress;
if (ip == null)
return false; return Compare(ip) == 0;
} public override int GetHashCode()
{
return this.ToString().GetHashCode();
} public override string ToString()
{
StringBuilder builder = new StringBuilder();
foreach (byte part in parts)
{
builder.Append(part);
builder.Append(Constants.Point);
}
builder.Remove(builder.Length - 1, 1); return builder.ToString();
}
#endregion #region INullable Members public virtual bool IsNull
{
get { return false; }
} #endregion
} # region Null IPAddress Class internal sealed class NullIPAddress : IPAddress
{
private const string emptyIP = "0.0.0.0"; private static NullIPAddress self = new NullIPAddress(); //Should Never use it directly
private NullIPAddress()
: base(0,0,0,0)
{
} public static IPAddress Instance
{
get { return self; }
} #region Base Class Overrides public override uint TransferToUINT()
{
return 0;
} public override string ToString()
{
return emptyIP;
} public override bool IsNull
{
get { return true; }
} #endregion
} #endregion #region IPBadFormatException Class public class IPBadFormatException : ApplicationException
{
private const string ErrorMSG = "Bad Format IP Address!"; /// <summary>
/// do not allow creation of exception with no message
/// </summary>
public IPBadFormatException()
: base(ErrorMSG)
{
} /// <summary>
/// Constructor takes problem message and caught exception
/// invokes constructor on ApplicationException
/// </summary>
public IPBadFormatException(Exception ex)
: base(ErrorMSG, ex)
{
}
} #endregion}

using System;
using System.Collections.Generic;
using System.Text;
using HKH.Common;namespace HKH.Common.Network
{
public class IPRange
{
#region Private Variables private IPAddress startIP = IPAddress.Null;
private IPAddress endIP = IPAddress.Null; #endregion #region Constructor
public IPRange(IPAddress startIP, IPAddress endIP)
{
this.startIP = startIP;
this.endIP = endIP;
} #endregion #region Properties
public IPAddress StartIP
{
get { return startIP; }
} public IPAddress EndIP
{
get { return endIP; }
}
#endregion #region Methods
public bool IsInclude(IPAddress ip)
{
return !(startIP.Compare(ip) > 0 || endIP.Compare(ip) < 0);
} public bool HasIntersection(IPRange ipRange)
{
return this.IsInclude(ipRange.startIP) || this.IsInclude(ipRange.endIP);
} public IPRange GetIntersection(IPRange ipRange)
{
if (!HasIntersection(ipRange))
throw new InvalidOperationException("The IPRanges don't have Intersection."); return new IPRange(this.IsInclude(ipRange.startIP) ? ipRange.startIP : this.startIP,
this.IsInclude(ipRange.endIP) ? ipRange.endIP : this.endIP);
} public IPRange Merge(IPRange ipRange)
{
if (!HasIntersection(ipRange))
throw new InvalidOperationException("The IPRanges don't have Intersection."); return new IPRange(this.IsInclude(ipRange.startIP) ? this.startIP : ipRange.startIP,
this.IsInclude(ipRange.endIP) ? this.endIP : ipRange.endIP);
}
#endregion #region Base Overrides public override bool Equals(object obj)
{
if (obj == null)
return false; IPRange ipRange = obj as IPRange;
if (ipRange == null)
return false; return this.startIP.Equals(ipRange.startIP) && this.endIP.Equals(ipRange.endIP);
} public override int GetHashCode()
{
return this.ToString().GetHashCode();
} public override string ToString()
{
StringBuilder builder = new StringBuilder(); builder.Append(startIP.ToString());
builder.Append(Constants.WhiteSpace);
builder.Append(Constants.Minus);
builder.Append(Constants.WhiteSpace);
builder.Append(endIP.ToString()); return builder.ToString();
}
#endregion }
}

让我修改一下2楼的代码：IPAddress ip;
if (IPAddress.TryParse(textBox1.Text, out ip) && textBox1.Text.Split('.').Length == 4)
{
MessageBox.Show("合法！");
}
else
{
MessageBox.Show("不合法！");
}

调试易

用c#语言怎么判断IP地址是否有效？

解决方案 »