public class IEProxySetting    {        public static bool UnsetProxy()        {            return SetProxy(null, null);        }        public static bool SetProxy(string strProxy)        {            return SetProxy(strProxy, null);        }        public static bool SetProxy(string strProxy, string exceptions)        {            InternetPerConnOptionList list = new InternetPerConnOptionList();            int optionCount = string.IsNullOrEmpty(strProxy) ? 1 : (string.IsNullOrEmpty(exceptions) ? 2 : 3);            InternetConnectionOption[] options = new InternetConnectionOption[optionCount];            // USE a proxy server ...            options[0].m_Option = PerConnOption.INTERNET_PER_CONN_FLAGS;            options[0].m_Value.m_Int = (int)((optionCount < 2) ? PerConnFlags.PROXY_TYPE_DIRECT : (PerConnFlags.PROXY_TYPE_DIRECT | PerConnFlags.PROXY_TYPE_PROXY));            // use THIS proxy server            if (optionCount > 1)            {                options[1].m_Option = PerConnOption.INTERNET_PER_CONN_PROXY_SERVER;                options[1].m_Value.m_StringPtr = Marshal.StringToHGlobalAuto(strProxy);                // except for these addresses ...                if (optionCount > 2)                {                    options[2].m_Option = PerConnOption.INTERNET_PER_CONN_PROXY_BYPASS;                    options[2].m_Value.m_StringPtr = Marshal.StringToHGlobalAuto(exceptions);                }            }            // default stuff            list.dwSize = Marshal.SizeOf(list);            list.szConnection = IntPtr.Zero;            list.dwOptionCount = options.Length;            list.dwOptionError = 0;            int optSize = Marshal.SizeOf(typeof(InternetConnectionOption));            // make a pointer out of all that ...            IntPtr optionsPtr = Marshal.AllocCoTaskMem(optSize * options.Length);            // copy the array over into that spot in memory ...            for (int i = 0; i < options.Length; ++i)            {                IntPtr opt = new IntPtr(optionsPtr.ToInt32() + (i * optSize));                Marshal.StructureToPtr(options[i], opt, false);            }            list.options = optionsPtr;            // and then make a pointer out of the whole list            IntPtr ipcoListPtr = Marshal.AllocCoTaskMem((Int32)list.dwSize);            Marshal.StructureToPtr(list, ipcoListPtr, false);            // and finally, call the API method!            int returnvalue = NativeMethods.InternetSetOption(IntPtr.Zero,               InternetOption.INTERNET_OPTION_PER_CONNECTION_OPTION,               ipcoListPtr, list.dwSize) ? -1 : 0;            if (returnvalue == 0)            {  // get the error codes, they might be helpful                returnvalue = Marshal.GetLastWin32Error();            }            // FREE the data ASAP            Marshal.FreeCoTaskMem(optionsPtr);            Marshal.FreeCoTaskMem(ipcoListPtr);            if (returnvalue > 0)            {  // throw the error codes, they might be helpful                throw new Win32Exception(Marshal.GetLastWin32Error());            }            return (returnvalue < 0);        }        /// 
        /// 获取正在使用的代理        /// 
        /// 
             public static string GetProxyServer()        {            //打开注册表             RegistryKey regKey = Registry.CurrentUser;            string SubKeyPath = "Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings";            //更改健值，设置代理            RegistryKey optionKey = regKey.OpenSubKey(SubKeyPath, true);            //是否启用 1 启用            int actualProxyStatus = Convert.ToInt32(optionKey.GetValue("ProxyEnable"));            string actualProxy = string.Empty;            if (actualProxyStatus == 1)            {                actualProxy = optionKey.GetValue("ProxyServer").ToString();            }            regKey.Close();            return actualProxy;        }    }    #region WinInet structures    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]    public struct InternetPerConnOptionList    {        public int dwSize;               // size of the INTERNET_PER_CONN_OPTION_LIST struct        public IntPtr szConnection;         // connection name to set/query options        public int dwOptionCount;        // number of options to set/query        public int dwOptionError;           // on error, which option failed        //[MarshalAs(UnmanagedType.)]        public IntPtr options;    };    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]    public struct InternetConnectionOption    {        static readonly int Size;        public PerConnOption m_Option;        public InternetConnectionOptionValue m_Value;        static InternetConnectionOption()        {            InternetConnectionOption.Size = Marshal.SizeOf(typeof(InternetConnectionOption));        }        // Nested Types        [StructLayout(LayoutKind.Explicit)]        public struct InternetConnectionOptionValue        {            // Fields            [FieldOffset(0)]            public System.Runtime.InteropServices.ComTypes.FILETIME m_FileTime;            [FieldOffset(0)]            public int m_Int;            [FieldOffset(0)]            public IntPtr m_StringPtr;        }    }    #endregion    #region WinInet enums    //    // options manifests for Internet{Query|Set}Option    //    public enum InternetOption : uint    {        INTERNET_OPTION_PER_CONNECTION_OPTION = 75    }    //    // Options used in INTERNET_PER_CONN_OPTON struct    //    public enum PerConnOption    {        INTERNET_PER_CONN_FLAGS = 1, // Sets or retrieves the connection type. The Value member will contain one or more of the values from PerConnFlags         INTERNET_PER_CONN_PROXY_SERVER = 2, // Sets or retrieves a string containing the proxy servers.          INTERNET_PER_CONN_PROXY_BYPASS = 3, // Sets or retrieves a string containing the URLs that do not use the proxy server.          INTERNET_PER_CONN_AUTOCONFIG_URL = 4//, // Sets or retrieves a string containing the URL to the automatic configuration script.      }    //    // PER_CONN_FLAGS    //    [Flags]    public enum PerConnFlags    {        PROXY_TYPE_DIRECT = 0x00000001,  // direct to net        PROXY_TYPE_PROXY = 0x00000002,  // via named proxy        PROXY_TYPE_AUTO_PROXY_URL = 0x00000004,  // autoproxy URL        PROXY_TYPE_AUTO_DETECT = 0x00000008   // use autoproxy detection    }    #endregion    internal static class NativeMethods    {        [DllImport("WinInet.dll", SetLastError = true, CharSet = CharSet.Auto)]        [return: MarshalAs(UnmanagedType.Bool)]        public static extern bool InternetSetOption(IntPtr hInternet, InternetOption dwOption, IntPtr lpBuffer, int dwBufferLength);    }