一楼喂熊

Option Explicit
Private Declare Function internetsetoption Lib "wininet.dll" Alias "InternetSetOptionA" _
(ByVal hinternet As Long, ByVal dwoption As Long, ByRef lpbuffer As Any, ByVal dwbufferlength As Long) As Long
Private Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
Private Declare Function RegCreateKey Lib "advapi32.dll" Alias "RegCreateKeyA" (ByVal hKey As Long, ByVal lpSubKey As String, phkResult As Long) As Long
Private Declare Function RegSetValueEx Lib "advapi32.dll" Alias "RegSetValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal Reserved As Long, ByVal dwType As Long, lpData As Any, ByVal cbData As Long) As Long ' Note that if you declare the lpData parameter as String, you must pass it By Value.
Private Const REG_DWORD As Long = 4
Private Const REG_SZ = 1
Private Const HKEY_CURRENT_USER = &H80000001
Private Sub SetSurrogate(address As String, Port As String) '设置代理服务器的地址跟端口
Dim str As String
Dim SubKey As String
Dim hKey As Long
str = Trim(address) & ":" & Trim(Port)
SubKey = "Software\Microsoft\Windows\CurrentVersion\Internet Settings\"
RegCreateKey HKEY_CURRENT_USER, SubKey, hKey
RegSetValueEx hKey, "ProxyServer", 0, REG_SZ, ByVal str, LenB(StrConv(str, vbFromUnicode)) + 1
RegCloseKey hKey
End Sub
Private Sub SetEnable()
Dim SubKey As String
Dim hKey As Long
SubKey = "Software\Microsoft\Windows\CurrentVersion\Internet Settings\"
RegCreateKey HKEY_CURRENT_USER, SubKey, hKey
RegSetValueEx hKey, "ProxyEnable", 0, REG_DWORD, 1&, 4
RegCloseKey hKey
End Sub
Private Sub SetDisable()
Dim SubKey As String
Dim hKey As Long
SubKey = "Software\Microsoft\Windows\CurrentVersion\Internet Settings\"
RegCreateKey HKEY_CURRENT_USER, SubKey, hKey
RegSetValueEx hKey, "ProxyEnable", 0, REG_DWORD, 0&, 4
RegCloseKey hKey
End Sub
Private Sub Command1_Click() '使代理服务器可用
SetSurrogate "125.88.75.151", "3128"
SetEnable
Call internetsetoption(0, 39, 0, 0)
End Sub
Private Sub Command2_Click() '使代理服务器不可用
SetDisable
Call internetsetoption(0, 39, 0, 0)
End Sub

请问，为什么可以设置代理，但是不能取消代理就没反应呢？

顶啊

1.注册表不用设置的,internetsetoption足够了
2.这个api也不是这样用的.传过去一个类型的
看这里:http://technet.microsoft.com/zh-cn/aa385148
INTERNET_OPEN_TYPE_PROXY是使用代理,INTERNET_OPEN_TYPE_DIRECT是不使用代理

Private Function SetProxy(ByVal Proxy As String)
Dim Options As INTERNET_PROXY_INFO
Options.dwAccessType = INTERNET_OPEN_TYPE_PROXY
Options.lpszProxy = Proxy
Options.lpszProxyBypass = ""
InternetSetOption 0, INTERNET_OPTION_PROXY, Options, LenB(Options)
InternetSetOption INTERNET_OPTION_SETTINGS_CHANGED, 0, 0, 0
End Function
常数就自己搜吧