change proxy with webbrowser control

' The structure we use for the information
' to be interpreted correctly by API.
Public Structure Struct_INTERNET_PROXY_INFO
    Public dwAccessType As Integer
    Public proxy As IntPtr
    Public proxyBypass As IntPtr
End Structure

' The Windows API function that allows us to manipulate
' IE settings programmatically.
Private Declare Auto Function InternetSetOption Lib "wininet.dll" _
(ByVal hInternet As IntPtr, ByVal dwOption As Integer, ByVal lpBuffer As IntPtr, _
 ByVal lpdwBufferLength As Integer) As Boolean

' The function we will be using to set the proxy settings.
Private Sub RefreshIESettings(ByVal strProxy As String)
    Const INTERNET_OPTION_PROXY As Integer = 38
    Const INTERNET_OPEN_TYPE_PROXY As Integer = 3
    Dim struct_IPI As Struct_INTERNET_PROXY_INFO

    ' Filling in structure
    struct_IPI.dwAccessType = INTERNET_OPEN_TYPE_PROXY
    struct_IPI.proxy = System.Runtime.InteropServices.Marshal.StringToHGlobalAnsi(strProxy)
    struct_IPI.proxyBypass = System.Runtime.InteropServices.Marshal.StringToHGlobalAnsi("local")

    ' Allocating memory
    Dim intptrStruct As IntPtr = System.Runtime.InteropServices.Marshal.AllocCoTaskMem(System.Runtime.InteropServices.Marshal.SizeOf(struct_IPI))

    ' Converting structure to IntPtr
    System.Runtime.InteropServices.Marshal.StructureToPtr(struct_IPI, intptrStruct, True)
    Dim iReturn As Boolean = InternetSetOption(IntPtr.Zero, INTERNET_OPTION_PROXY, intptrStruct, System.Runtime.InteropServices.Marshal.SizeOf(struct_IPI))
End Sub

RefreshIESettings("127.0.0.1:8080")

http://www.vbdotnetheaven.com/UploadFile/mahesh/DownloadWebPage04252005073432AM/DownloadWebPage.aspx

http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.aspx

http://www.worldofasp.net/tut/WebRequest/Working_with_HttpWebRequest_and_HttpWebResponse_in_ASPNET_114.aspx