非常有用的操作INTERNET的API函数

导读：
　　必须安装有Winnet.dll文件, 功能比WINSOCK强大. 但MSDN里的说明和例子都是C++的,连VB的都没有. 我自己试探出这么一些功能.
　　先贴出来供大家参考.
　　*所有函数如果运行失败,返回 0 成功返回1或者句柄.
　　*参数大部分是用默认的,参数具体内容,查帮助文件
　　1.检查INTERNET是否连通
　　DECLARE Integer InternetGetConnectedState IN "wininet.dll" Integer,Integer
　　 InternetGetConnectedState(0,0)
　　2.自动拨号-使用默认的拨号连接 (IE的INTERNET连接设置里必须设置拨号连接, 另外还有个InternetDial函数,必须使用拨号连接名称)
　　DECLARE Integer InternetAutodial IN "wininet.dll" Integer,Integer
　　 InternetAutodial (0,0)
　　3.自动中断拨号或者连接
　　DECLARE Integer InternetAutodialHangup IN "wininet.dll" Integer
　　 InternetAutodialHangup(0)
　　4. 获得一个连接句柄
　　Declare Integer InternetOpen IN "wininet.dll" String, Integer, String, String, Integer
　　lnOpen= internetOpen("MyFtp",1,null,null,0)
　　5. 连接到FTP SERVER
　　Declare Integer InternetConnect in "wininet.dll" Integer,String,Integer,String, String, Integer, Integer, Integer
　　lnConn=InternetConnect(lnOpen, "ftp.microsoft.com",0 , "anonymous", "[email protected]", 1, 0, 0)
　　6. 下载一个文件. 还有不少FTP或者HTTP的操作文件或页面的函数. 有兴趣者自己去试
　　Declare Integer FtpGetFile in "wininet.dll" Integer, String, String, Integer, Integer,Integer,Integer
　　 FtpGetFile(lnConn,/bussys/readme.txt,c:/Temp/msreadme.txt,0,0,1,0)
　　7. 中断连接
　　Declare Integer InternetCloseHandle In "wininet.dll" Integer
　　 InternetCloseHandle(lnConn)
　　下面是WININET.DLL里大部分的API函数,是用VB格式的声明:
　　Declare Function GetProcessHeap Lib "kernel32" () As Long
　　Declare Function HeapAlloc Lib "kernel32" (ByVal hHeap As Long, ByVal dwFlags As Long, ByVal dwBytes As Long) As Long
　　Declare Function HeapFree Lib "kernel32" (ByVal hHeap As Long, ByVal dwFlags As Long, lpMem As Any) As Long
　　Declare Sub CopyMemory1 Lib "kernel32" Alias "RtlMoveMemory" ( _
　　hpvDest As Any, ByVal hpvSource As Long, ByVal cbCopy As Long)
　　Declare Sub CopyMemory2 Lib "kernel32" Alias "RtlMoveMemory" ( _
　　hpvDest As Long, hpvSource As Any, ByVal cbCopy As Long)
　　Public Const ERROR_NO_MORE_FILES = 18
　　Public Declare Function InternetFindNextFile Lib "wininet.dll" Alias "InternetFindNextFileA" _
　　(ByVal hFind As Long, lpvFindData As WIN32_FIND_DATA) As Long
　　Public Declare Function FtpFindFirstFile Lib "wininet.dll" Alias "FtpFindFirstFileA" _
　　(ByVal hFtpSession As Long, ByVal lpszSearchFile As String, _
　　lpFindFileData As WIN32_FIND_DATA, ByVal dwFlags As Long, ByVal dwContent As Long) As Long
　　Public Declare Function FtpGetFile Lib "wininet.dll" Alias "FtpGetFileA" _
　　(ByVal hFtpSession As Long, ByVal lpszRemoteFile As String, _
　　ByVal lpszNewFile As String, ByVal fFailIfExists As Boolean, ByVal dwFlagsAndAttributes As Long, _
　　ByVal dwFlags As Long, ByVal dwContext As Long) As Boolean
　　Public Declare Function FtpPutFile Lib "wininet.dll" Alias "FtpPutFileA" _
　　(ByVal hFtpSession As Long, ByVal lpszLocalFile As String, _
　　ByVal lpszRemoteFile As String, _
　　ByVal dwFlags As Long, ByVal dwContext As Long) As Boolean
　　Public Declare Function FtpSetCurrentDirectory Lib "wininet.dll" Alias "FtpSetCurrentDirectoryA" _
　　(ByVal hFtpSession As Long, ByVal lpszDirectory As String) As Boolean
　　Public Declare Function FtpGetCurrentDirectory Lib "wininet.dll" Alias "FtpGetCurrentDirectoryA" _
　　(ByVal hFtpSession As Long, ByVal lpszDirectory As String, ByRef lpdwCurrentDirectory As Long) As Boolean
　　Initializes an applications use of the Win32 Internet functions
　　Public Declare Function InternetOpen Lib "wininet.dll" Alias "InternetOpenA" _
　　(ByVal sAgent As String, ByVal lAccessType As Long, ByVal sProxyName As String, _
　　ByVal sProxyBypass As String, ByVal lFlags As Long) As Long
　　Opens a HTTP session for a given site.
　　Public Declare Function InternetConnect Lib "wininet.dll" Alias "InternetConnectA" _
　　(ByVal hInternetSession As Long, ByVal sServerName As String, ByVal nServerPort As Integer, _
　　ByVal sUsername As String, ByVal sPassword As String, ByVal lService As Long, _
　　ByVal lFlags As Long, ByVal lContext As Long) As Long
　　Public Declare Function InternetGetLastResponseInfo Lib "wininet.dll" Alias "InternetGetLastResponseInfoA" ( _
　　lpdwError As Long, _
　　ByVal lpszBuffer As String, _
　　lpdwBufferLength As Long) As Boolean
　　Type of service to access.
　　Opens an HTTP request handle.
　　Public Declare Function HttpOpenRequest Lib "wininet.dll" Alias "HttpOpenRequestA" _
　　(ByVal hHttpSession As Long, ByVal sVerb As String, ByVal sObjectName As String, ByVal sVersion As String, _
　　ByVal sReferer As String, ByVal something As Long, ByVal lFlags As Long, ByVal lContext As Long) As Long
　　Sends the specified request to the HTTP server.
　　Public Declare Function HttpSendRequest Lib "wininet.dll" Alias "HttpSendRequestA" (ByVal _
　　hHttpRequest As Long, ByVal sHeaders As String, ByVal lHeadersLength As Long, ByVal sOptional As _
　　String, ByVal lOptionalLength As Long) As Integer
　　Queries for information about an HTTP request.
　　Public Declare Function HttpQueryInfo Lib "wininet.dll" Alias "HttpQueryInfoA" _
　　(ByVal hHttpRequest As Long, ByVal lInfoLevel As Long, ByRef sBuffer As Any, _
　　ByRef lBufferLength As Long, ByRef lIndex As Long) As Integer
　　InternetErrorDlg
　　Public Declare Function InternetErrorDlg Lib "wininet.dll" _
　　(ByVal hWnd As Long, ByVal hInternet As Long, ByVal dwError As Long, ByVal dwFlags As Long, ByVal lppvData As Long) As Long
　　Public Declare Function GetDesktopWindow Lib "user32.dll" () As Long
　　The possible values for the lInfoLevel parameter include:
　　Reads data from a handle opened by the HttpOpenRequest function.
　　Public Declare Function InternetReadFile Lib "wininet.dll" _
　　(ByVal hFile As Long, ByVal sBuffer As String, ByVal lNumBytesToRead As Long, _
　　lNumberOfBytesRead As Long) As Integer
　　Public Declare Function HttpSendRequestEx Lib "wininet.dll" Alias "HttpSendRequestExA" _
　　(ByVal hHttpRequest As Long, lpBuffersIn As INTERNET_BUFFERS, ByVal lpBuffersOut As Long, _
　　ByVal dwFlags As Long, ByVal dwContext As Long) As Long
　　Public Declare Function HttpEndRequest Lib "wininet.dll" Alias "HttpEndRequestA" _
　　(ByVal hHttpRequest As Long, ByVal lpBuffersOut As Long, _
　　ByVal dwFlags As Long, ByVal dwContext As Long) As Long
　　Public Declare Function InternetWriteFile Lib "wininet.dll" _
　　(ByVal hFile As Long, ByVal sBuffer As String, _
　　ByVal lNumberOfBytesToRead As Long, _
　　lNumberOfBytesRead As Long) As Integer
　　Public Declare Function FtpOpenFile Lib "wininet.dll" Alias _
　　"FtpOpenFileA" (ByVal hFtpSession As Long, _
　　ByVal sFileName As String, ByVal lAccess As Long, _
　　ByVal lFlags As Long, ByVal lContext As Long) As Long
　　Public Declare Function FtpDeleteFile Lib "wininet.dll" _
　　Alias "FtpDeleteFileA" (ByVal hFtpSession As Long, _
　　ByVal lpszFileName As String) As Boolean
　　Public Declare Function InternetSetOption Lib "wininet.dll" Alias "InternetSetOptionA" _
　　(ByVal hInternet As Long, ByVal lOption As Long, ByRef sBuffer As Any, ByVal lBufferLength As Long) As Integer
　　Public Declare Function InternetSetOptionStr Lib "wininet.dll" Alias "InternetSetOptionA" _
　　(ByVal hInternet As Long, ByVal lOption As Long, ByVal sBuffer As String, ByVal lBufferLength As Long) As Integer
　　Closes a single Internet handle or a subtree of Internet handles.
　　Public Declare Function InternetCloseHandle Lib "wininet.dll" _
　　(ByVal hInet As Long) As Integer
　　Queries an Internet option on the specified handle
　　Public Declare Function InternetQueryOption Lib "wininet.dll" Alias "InternetQueryOptionA" _
　　(ByVal hInternet As Long, ByVal lOption As Long, ByRef sBuffer As Any, ByRef lBufferLength As Long) As Integer
　　Returns the version number of Wininet.dll.
　　Public Const INTERNET_OPTION_VERSION = 40
　　Contains the version number of the DLL that contains the Windows Internet
　　functions (Wininet.dll). This structure is used when passing the
　　INTERNET_OPTION_VERSION flag to the InternetQueryOption function.
　　Adds one or more HTTP request headers to the HTTP request handle.
　　Public Declare Function HttpAddRequestHeaders Lib "wininet.dll" Alias "HttpAddRequestHeadersA" _
　　(ByVal hHttpRequest As Long, ByVal sHeaders As String, ByVal lHeadersLength As Long, _
　　ByVal lModifiers As Long) As Integer
　　Flags to modify the semantics of this function. Can be a combination of these values:
　　Public Declare Function InternetDial Lib "wininet.dll" _
　　(ByVal hWnd As Long, ByVal sConnectoid As String, _
　　ByVal dwFlags As Long, lpdwConnection As Long, ByVal dwReserved As Long) As Long
　　Public Declare Function InternetHangUp Lib "wininet.dll" _
　　(ByVal dwConnection As Long, ByVal dwReserved As Long) As Long
　　Public Declare Function InternetOpenUrl Lib "wininet.dll" Alias "InternetOpenUrlA" _
　　(ByVal hInternetSession As Long, ByVal sUrl As String, _
　　ByVal sHeaders As String, ByVal lHeadersLength As Long, _
　　ByVal lFlags As Long, ByVal lContext As Long) As Long

本文转自
http://www.java-asp.net/aspnet/200512/t_44001.html