How do you parse an IP address string to a uint value in C#?

Question

I\'m writing C# code that uses the windows IP Helper API. One of the functions I\'m trying to call is \"GetBestInterface\" that takes a \'uint\' representation of an IP. Wha

Answer 1

Complete solution:

public static uint IpStringToUint(string ipString)
{
    var ipAddress = IPAddress.Parse(ipString);
    var ipBytes = ipAddress.GetAddressBytes();
    var ip = (uint)ipBytes [0] << 24;
    ip += (uint)ipBytes [1] << 16;
    ip += (uint)ipBytes [2] <<8;
    ip += (uint)ipBytes [3];
    return ip;
}

public static string IpUintToString(uint ipUint)
{
    var ipBytes = BitConverter.GetBytes(ipUint);
    var ipBytesRevert = new byte[4];
    ipBytesRevert[0] = ipBytes[3];
    ipBytesRevert[1] = ipBytes[2];
    ipBytesRevert[2] = ipBytes[1];
    ipBytesRevert[3] = ipBytes[0];
    return new IPAddress(ipBytesRevert).ToString();
}

Reverse order of bytes:

public static uint IpStringToUint(string ipString)
{
    return BitConverter.ToUInt32(IPAddress.Parse(ipString).GetAddressBytes(), 0);
}

public static string IpUintToString(uint ipUint)
{
    return new IPAddress(BitConverter.GetBytes(ipUint)).ToString();
}

You can test here:

https://www.browserling.com/tools/dec-to-ip

http://www.smartconversion.com/unit_conversion/IP_Address_Converter.aspx

http://www.silisoftware.com/tools/ipconverter.php

Answer 2

Byte arithmetic is discouraged, as it relies on all IPs being 4-octet ones.

Answer 3

System.Net.IPAddress ipAddress = System.Net.IPAddress.Parse("192.168.1.1");

byte[] bytes = ipAddress.GetAddressBytes();
for (int i = 0; i < bytes.Length ; i++)
       Console.WriteLine(bytes[i]);

Output will be 192 168 1 1

Answer 4

Correct solution that observes Endianness:

var ipBytes = ip.GetAddressBytes();
ulong ip = 0;
if (BitConverter.IsLittleEndian)
{
    ip = (uint) ipBytes[0] << 24;
    ip += (uint) ipBytes[1] << 16;
    ip += (uint) ipBytes[2] << 8;
    ip += (uint) ipBytes[3];
}
else
{
    ip = (uint)ipBytes [3] << 24;
    ip += (uint)ipBytes [2] << 16;
    ip += (uint)ipBytes [1] <<8;
    ip += (uint)ipBytes [0];
}

Answer 5

Shouldn't it be:

var ipAddress = IPAddress.Parse("some.ip.address");
var ipBytes = ipAddress.GetAddressBytes();
var ip = (uint)ipBytes [0] << 24;
ip += (uint)ipBytes [1] << 16;
ip += (uint)ipBytes [2] <<8;
ip += (uint)ipBytes [3];

?

Answer 6

I have never found a clean solution (i.e.: a class / method in the .NET Framework) for this problem. I guess it just isn't available except the solutions / examples you provided or Aku's example. :(