c#webbrowser设置代理ip

使用api设置代理ip访问网站。

    #region 设置代理ip
        //strProxy为代理IP:端口
        private void RefreshIESettings(string strProxy)
        {
            const int INTERNET_OPTION_PROXY = 38;
            const int INTERNET_OPEN_TYPE_PROXY = 3;
            const int INTERNET_OPEN_TYPE_DIRECT = 1;

            IEProxy.Struct_INTERNET_PROXY_INFO struct_IPI;
            // Filling in structure
            struct_IPI.dwAccessType = INTERNET_OPEN_TYPE_PROXY;
            struct_IPI.proxy = Marshal.StringToHGlobalAnsi(strProxy);
            struct_IPI.proxyBypass = Marshal.StringToHGlobalAnsi("local");

            // Allocating memory
            IntPtr intptrStruct = Marshal.AllocCoTaskMem(Marshal.SizeOf(struct_IPI));
            if (string.IsNullOrEmpty(strProxy) || strProxy.Trim().Length == 0)
            {
                strProxy = string.Empty;
                struct_IPI.dwAccessType = INTERNET_OPEN_TYPE_DIRECT;

            }
            // Converting structure to IntPtr
            Marshal.StructureToPtr(struct_IPI, intptrStruct, true);

            bool iReturn = InternetSetOption(IntPtr.Zero, INTERNET_OPTION_PROXY, intptrStruct, Marshal.SizeOf(struct_IPI));
        }

        [DllImport("wininet.dll", SetLastError = true)]
        private static extern bool InternetSetOption(IntPtr hInternet, int dwOption, IntPtr lpBuffer, int lpdwBufferLength);
        public class IEProxy
        {
            private const int INTERNET_OPTION_PROXY = 38;
            private const int INTERNET_OPEN_TYPE_PROXY = 3;
            private const int INTERNET_OPEN_TYPE_DIRECT = 1;

            private string ProxyStr;


            [DllImport("wininet.dll", SetLastError = true)]

            private static extern bool InternetSetOption(IntPtr hInternet, int dwOption, IntPtr lpBuffer, int lpdwBufferLength);

            public struct Struct_INTERNET_PROXY_INFO
            {
                public int dwAccessType;
                public IntPtr proxy;
                public IntPtr proxyBypass;
            }

            private bool InternetSetOption(string strProxy)
            {
                int bufferLength;
                IntPtr intptrStruct;
                Struct_INTERNET_PROXY_INFO struct_IPI;

                if (string.IsNullOrEmpty(strProxy) || strProxy.Trim().Length == 0)
                {
                    strProxy = string.Empty;
                    struct_IPI.dwAccessType = INTERNET_OPEN_TYPE_DIRECT;
                }
                else
                {
                    struct_IPI.dwAccessType = INTERNET_OPEN_TYPE_PROXY;
                }
                struct_IPI.proxy = Marshal.StringToHGlobalAnsi(strProxy);
                struct_IPI.proxyBypass = Marshal.StringToHGlobalAnsi("local");
                bufferLength = Marshal.SizeOf(struct_IPI);
                intptrStruct = Marshal.AllocCoTaskMem(bufferLength);
                Marshal.StructureToPtr(struct_IPI, intptrStruct, true);
                return InternetSetOption(IntPtr.Zero, INTERNET_OPTION_PROXY, intptrStruct, bufferLength);

            }
            public IEProxy(string strProxy)
            {
                this.ProxyStr = strProxy;
            }
            //设置代理
            public bool RefreshIESettings()
            {
                return InternetSetOption(this.ProxyStr);
            }
            //取消代理
            public bool DisableIEProxy()
            {
                return InternetSetOption(string.Empty);
            }
        }
        #endregion
        
               //清空session
        public void ResetSession()
        {
            //Session的选项ID为42
            InternetSetOption(IntPtr.Zero, 42, IntPtr.Zero, 0);
        }
        
                //清空cookie
        public void ResetCookie()
        {
            if (webBrowser1.Document != null)
            {
                webBrowser1.Document.Cookie.Remove(0, webBrowser1.Document.Cookie.Count() - 1);

            }
            string[] theCookies = System.IO.Directory.GetFiles(Environment.GetFolderPath(Environment.SpecialFolder.Cookies));
            foreach (string currentFile in theCookies)
            {
                try
                {
                    System.IO.File.Delete(currentFile);
                }
                catch (Exception ex)
                {
                }
            }
        }