ホスト名とIPアドレスを相互に変換する方法

ホスト名とIPアドレスを相互に変換する方法
Dns.GetHostEntryでIPアドレスのリストを取得する方法
VB.NET

Dim hostName As String = "www.testserver.co.jp"

Dim iphe As System.Net.IPHostEntry = System.Net.Dns.GetHostEntry(hostName)

Dim adList As System.Net.IPAddress() = iphe.AddressList
Dim i As Integer
For i = 0 To adList.Length - 1
    Console.WriteLine(adList(i).ToString())
Next

C#

string hostName = "www.testserver.co.jp";

System.Net.IPHostEntry iphe = System.Net.Dns.GetHostEntry(hostName);

System.Net.IPAddress[] adList = iphe.AddressList;

for (int i = 0; i < adList.Length; i++)
{
    Console.WriteLine(adList[i].ToString());
}

IPアドレスをホスト名に変換する方法
VB.NET

Dim ipAdd As String = "192.168.10.１００"

Dim iphe As System.Net.IPHostEntry = System.Net.Dns.GetHostEntry(ipAdd)

Console.WriteLine(iphe.HostName)

C#

string ipAdd = "192.168.10.１００";

System.Net.IPHostEntry iphe = System.Net.Dns.GetHostEntry(ipAdd);

Console.WriteLine(iphe.HostName);

非同期でIPアドレス一覧を取得する方法
VB.NET

Private Sub btn1_Click(sender As Object, e As EventArgs) _
    Handles btn1.Click

    Dim hostName As String = "www.testserver.co.jp"

    System.Net.Dns.BeginGetHostEntry(hostName, _
        New AsyncCallback(AddressOf GetHostEntryCallback), Nothing)
End Sub

Public Shared Sub GetHostEntryCallback(ar As IAsyncResult)
    Dim iphe As System.Net.IPHostEntry = System.Net.Dns.EndGetHostEntry(ar)

    Dim adList As System.Net.IPAddress() = iphe.AddressList

    Dim i As Integer
    For i = 0 To adList.Length - 1
        Console.WriteLine(adList(i).ToString())
    Next
End Sub

C#

private void btn1_Click(object sender, EventArgs e)
{
    string hostName = "www.testserver.co.jp";

    System.Net.Dns.BeginGetHostEntry(hostName,
        new AsyncCallback(GetHostEntryCallback), null);
}

public static void GetHostEntryCallback(IAsyncResult ar)
{
    System.Net.IPHostEntry iphe = System.Net.Dns.EndGetHostEntry(ar);

    System.Net.IPAddress[] adList = iphe.AddressList;

    for (int i = 0; i < adList.Length; i++)
    {
        Console.WriteLine(adList[i].ToString());
    }
}

Dns.GetHostAddressesでIPアドレス一覧を取得する方法
VB.NET

Dim hostName As String = "www.testserver.co.jp"

Dim adList As System.Net.IPAddress() = _
    System.Net.Dns.GetHostAddresses(hostName)

Dim i As Integer
For i = 0 To adList.Length - 1
    Console.WriteLine(adList(i).ToString())
Next

C#

string hostName = "www.testserver.co.jp";

System.Net.IPAddress[] adList = System.Net.Dns.GetHostAddresses(hostName);

for (int i = 0; i < adList.Length; i++)
{
    Console.WriteLine(adList[i].ToString());
}