由域名查IP的程序如何作？

[ltolll]

想用VB作一个好像PING一样的程序
可以在线状态下，由一个域名查它的IP地址，怎么编这个程序呢？

[liuzhanwen]

上次跟你说ping，看你没给分。这次给你代码。其中的connection3就是ping的方法

modFunction中：
Option Explicit

Public Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
Public Declare Function RegOpenKey Lib "advapi32.dll" Alias "RegOpenKeyA" _
(ByVal hKey As Long, ByVal lpSubKey As String, phkResult As Long) As Long
Public Declare Function RegQueryValueEx Lib "advapi32.dll" Alias "RegQueryValueExA" _
(ByVal hKey As Long, ByVal lpValueName As String, ByVal lpReserved As Long, lpType As Long, _
lpData As Any, lpcbData As Long) As Long
Public Const ERROR_SUCCESS = 0&
Public Const APINULL = 0&
Public Const HKEY_LOCAL_MACHINE = &H80000002
Public Declare Function InternetGetConnectedStateEx Lib "wininet.dll" Alias _
"InternetGetConnectedStateExA" (ByRef lpdwFlags As Long, ByVal lpszConnectionName As String, _
ByVal dwNameLen As Long, ByVal dwReserved As Long) As Long

Public Const INTERNET_CONNECTION_MODEM = &H1&
Public Const INTERNET_CONNECTION_LAN = &H2&
Public Const INTERNET_CONNECTION_PROXY = &H4&
Public Const INTERNET_RAS_INSTALLED = &H10&
Public Const INTERNET_CONNECTION_OFFLINE = &H20&
Public Const INTERNET_CONNECTION_CONFIGURED = &H40&
Public Declare Function InternetOpen Lib "wininet.dll" Alias "InternetOpenA" _
(ByVal lpszAgent As String, ByVal dwAccessType As Long, ByVal lpszProxyName As String, _
ByVal lpszProxyBypass As String, ByVal dwFlags As Long) As Long
Public Declare Function InternetOpenUrl Lib "wininet.dll" Alias "InternetOpenUrlA" _
(ByVal hInet As Long, ByVal lpszUrl As String, ByVal lpszHeaders As String, _
ByVal dwHeadersLength As Long, ByVal dwFlags As Long, ByVal dwContext As Long) As Long
Public Declare Function InternetCloseHandle Lib "wininet.dll" (ByVal hInet As Long) As Long
Public Const INTERNET_OPEN_TYPE_PRECONFIG = 0
Public Const INTERNET_FLAG_RELOAD = &H80000000
Public Const INTERNET_FLAG_KEEP_CONNECTION = &H400000
Public Const INTERNET_FLAG_NO_CACHE_WRITE = &H400000

窗体中代码：
Option Explicit

Private Sub Form_Load()

Frame1.Caption = "探测方式"
opt1.Caption = "Modem"
opt2.Caption = "LAN/Modem"
opt3.Caption = "Ping"

End Sub

Private Sub cmdCheck_Click()

If opt1.Value Then
CheckConnection1
ElseIf opt2.Value Then
CheckConnection2
ElseIf opt3.Value Then
CheckConnection3
Else
MsgBox "您尚未选择探测方式", vbCritical, "出错"
Exit Sub
End If

End Sub

Private Sub cmdExit_Click()

Unload Me

End Sub

Private Sub CheckConnection1()

Dim ReturnCode As Long
Dim hKey As Long
Dim lpSubKey As String
Dim phkResult As Long
Dim lpValueName As String
Dim lpReserved As Long
Dim lpType As Long
Dim lpData As Long
Dim lpcbData As Long

lpSubKey = "System\CurrentControlSet\Services\RemoteAccess" & Chr$(0)
ReturnCode = RegOpenKey(HKEY_LOCAL_MACHINE, lpSubKey, phkResult)
If ReturnCode = ERROR_SUCCESS Then
hKey = phkResult
lpValueName = "Remote Connection"
lpReserved = APINULL
lpType = APINULL
lpData = APINULL
lpcbData = APINULL
ReturnCode = RegQueryValueEx(hKey, lpValueName, lpReserved, lpType, lpData, lpcbData)
If ReturnCode = ERROR_SUCCESS Then
If lpData = 0 Then
MsgBox "你的计算机未通过Modem连接", vbInformation, "连接检测"
Else
MsgBox "你的计算机通过Modem接通", vbInformation, "连接检测"
End If
Else
MsgBox "你的计算机未通过Modem连接,但可能通过LAN连接", vbInformation, "连接检测"
End If
End If
RegCloseKey (hKey)

End Sub

Private Sub CheckConnection2(Optional ByRef ConnectionInfo As Long, Optional ByRef sConnectionName As String)

Dim lFlags As Long
Dim sNameBuf As String, msg As String
Dim lPos As Long
sNameBuf = String$(513, 0)
If InternetGetConnectedStateEx(lFlags, sNameBuf, 512, 0&) Then
lPos = InStr(sNameBuf, vbNullChar)
If lPos > 0 Then
sConnectionName = Left$(sNameBuf, lPos - 1)
Else
sConnectionName = ""
End If
msg = "你的计算机已经接入Internet" & vbCrLf & "连接名:" & sConnectionName
If (lFlags And INTERNET_CONNECTION_LAN) Then
msg = msg & vbCrLf & "连接使用了LAN"
ElseIf (lFlags And INTERNET_CONNECTION_MODEM) Then
msg = msg & vbCrLf & "连接使用了Modem"
End If
If lFlags And INTERNET_CONNECTION_PROXY Then msg = msg & vbCrLf & "连接使用了Proxy"
If lFlags And INTERNET_RAS_INSTALLED Then
msg = msg & vbCrLf & "RAS已安装"
Else
msg = msg & vbCrLf & "RAS未安装"
End If
If lFlags And INTERNET_CONNECTION_OFFLINE Then
msg = msg & vbCrLf & "您不在线"
Else
msg = msg & vbCrLf & "您正在线"
End If
If lFlags And INTERNET_CONNECTION_CONFIGURED Then
msg = msg & vbCrLf & "您的连接已经配置"
Else
msg = msg & vbCrLf & "您的连接尚未配置"
End If
Else
msg = "您尚未接入Internet"
End If
MsgBox msg, vbInformation, "连接提示"

End Sub

Private Sub CheckConnection3()

Dim sTmp As sting
Dim hInet As Long
Dim hUrl As Long
Dim Flags As Long
Dim url As Variant
hInet = InternetOpen(App.Title, INTERNET_OPEN_TYPE_PRECONFIG, vbNullString, vbNullString, 0&)
sTmp = Me.Caption
Me.Caption = "通过 Ping WWW.CHINA.COM 检测..."
If hInet Then
Flags = INTERNET_FLAG_KEEP_CONNECTION Or INTERNET_FLAG_NO_CACHE_WRITE Or INTERNET_FLAG_RELOAD
hUrl = InternetOpenUrl(hInet, "http://www.china.com", vbNullString, 0, Flags, 0)
If hUrl Then
MsgBox "您的计算机已经接入Internet", vbInformation, "接入检测"
Call InternetCloseHandle(hUrl)
Else
MsgBox "您的计算机已经接入Internet", vbInformation, "接入检测"
End If
End If
Call InternetCloseHandle(hInet)
Me.Caption = sTmp

End Sub

[ltolll]

谢谢liuzhanwen(研究一下！)朋友的源码，但是它只能测知本机是否与要求的URL连通，而我的要求却是：

可以在线状态下，由一个域名查它的IP地址