C#设置IE代理及遇到问题的解决方案

　　起初使用的方法是修改完一次代理之后就不能继续修改，需要重新启动一次进程才可以，最初代码是：

private void ShowProxyInfo()
{
if (!GetProxyStatus())
{
lblInitInfo.Text = "代理未启用：";
}
else
{
lblInitInfo.Text = "当前使用的代理是：" + GetProxyServer();
}

}

private void InitProxyData()
{
List<string> proxyList = new List<string>{
"http://web-proxy.cup.hp.com:8080","http://proxy.compaq.com:8080"
};
combProxyList.DataSource = proxyList;
combProxyList.SelectedIndex = 0;
}
public void SetProxy(string proxy)
{
//打开注册表
//RegistryKey regKey = Registry.CurrentUser;
//string SubKeyPath = "Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings";
//RegistryKey optionKey = regKey.OpenSubKey(SubKeyPath, true);             //更改健值，设置代理，
//optionKey.SetValue("ProxyEnable", 1);
//optionKey.SetValue("ProxyServer", proxy);

////激活代理设置【用于即使IE没有关闭也能更新当前打开的IE中的代理设置。】
//InternetSetOption(0, 39, IntPtr.Zero, 0);
//InternetSetOption(0, 37, IntPtr.Zero, 0);
//regKey.Flush(); //刷新注册表
//regKey.Close();
//ShowProxyInfo();

using (RegistryKey regKey = Registry.CurrentUser)
{
string SubKeyPath = "Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings";
RegistryKey optionKey = regKey.OpenSubKey(SubKeyPath, true);             //更改健值，设置代理
optionKey.SetValue("ProxyEnable", 1);
optionKey.SetValue("ProxyServer", proxy);
//激活代理设置【用于即使IE没有关闭也能更新当前打开的IE中的代理设置。】
InternetSetOption(0, 39, IntPtr.Zero, 0);
InternetSetOption(0, 37, IntPtr.Zero, 0);
regKey.Flush(); //刷新注册表
ShowProxyInfo();
}

}

public void DisableProxy()
{
//打开注册表
RegistryKey regKey = Registry.CurrentUser;
string SubKeyPath = "Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings";
RegistryKey optionKey = regKey.OpenSubKey(SubKeyPath, true);             //更改健值，设置代理，
optionKey.SetValue("ProxyEnable", 0);
regKey.Flush(); //刷新注册表
InternetSetOption(0, 39, IntPtr.Zero, 0);
InternetSetOption(0, 37, IntPtr.Zero, 0);
regKey.Close();
ShowProxyInfo();
}

[DllImport(@"wininet", SetLastError = true, CharSet = CharSet.Auto,
EntryPoint = "InternetSetOption",
CallingConvention = CallingConvention.StdCall)]
public static extern bool InternetSetOption(
int hInternet, int dmOption, IntPtr lpBuffer, int dwBufferLength);

private void btnSetProxy_Click(object sender, EventArgs e)
{
string proxyStr = combProxyList.Text.Trim();
SetProxy(proxyStr);
var currentProxy = GetProxyServer();
if (currentProxy == proxyStr && GetProxyStatus())
{
lblInfo.Text = "设置代理：" + proxyStr + "成功！";
lblInfo.ForeColor = Color.Green;
}
else
{
if (!GetProxyStatus())
{
lblInfo.Text = "设置代理：" + proxyStr + "代理未启用！";

}
else
{
lblInfo.Text = "设置代理：" + proxyStr + "失败，正在使用" + currentProxy + "代理，请重试！";

}
lblInfo.ForeColor = Color.Red;
}
ShowProxyInfo();

}

/// <summary>
/// 获取正在使用的代理
/// </summary>
/// <returns></returns>
private string GetProxyServer()
{
//打开注册表
RegistryKey regKey = Registry.CurrentUser;
string SubKeyPath = "Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings";
RegistryKey optionKey = regKey.OpenSubKey(SubKeyPath, true);             //更改健值，设置代理，
string actualProxy = optionKey.GetValue("ProxyServer").ToString();
regKey.Close();
return actualProxy;
}

private bool GetProxyStatus()
{
//打开注册表
RegistryKey regKey = Registry.CurrentUser;
string SubKeyPath = "Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings";
RegistryKey optionKey = regKey.OpenSubKey(SubKeyPath, true);             //更改健值，设置代理，
int actualProxyStatus = Convert.ToInt32(optionKey.GetValue("ProxyEnable"));
regKey.Close();
return actualProxyStatus == 1 ? true : false;
}

//成功返回true，错误返回false
public Boolean prcessBaidu()
{
HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create("http://www.163.com");
myRequest.Method = "POST"; //采用post方式提交访问163主页 // Get response
try//当无法访问163网站时，下面的对象会有错误产生，所以用try..catch处理掉这些异常
{
Stream newStream = myRequest.GetRequestStream();//获取请求流     // Send the data.
newStream.Close();//关闭请求流
HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();//获取应答对象
StreamReader reader = new StreamReader(myResponse.GetResponseStream());//获取应答流
string content = reader.ReadToEnd();//将流对象读取到string 中
if (content.IndexOf("http://reg.163.com") > -1)//如果访问网站成功，则网页中包含置顶的关键字符串“http://reg.163.com”表示访问网页成功
{
return true;
}
else
{
return false;
}
}
catch (Exception ex)
{
return false;
}
return false;
}

private void btnDisableProxy_Click(object sender, EventArgs e)
{
DisableProxy();

if (!GetProxyStatus())
{
lblInfo.Text = "取消代理完成！";
lblInfo.ForeColor = Color.Green;
}
else
{
lblInfo.Text = "取消失败，正在使用代理" + GetProxyServer();
lblInfo.ForeColor = Color.Red;
}
ShowProxyInfo();
}

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{

}

private void btnTestProxy_Click(object sender, EventArgs e)
{
string proxyStr = combProxyList.SelectedText;
SetProxy(proxyStr);
if (prcessBaidu())
{
MessageBox.Show("代理可以正常访问。");
}
else
{
MessageBox.Show("目前无法使用代理！");
}
ShowProxyInfo();
}

　　有网友的结果是说在window7下， 在一个进程中， 设置和取消不能都执行，---- 要么设置，要么取消。 但如果第一次运行时，只进行设置代理，退出后再进运行，只进行取消，这是没有问题的。简单说说他给出的解决方案：每次设置或取消代理时，都新建一个进程，在新的进程中处理，处理完之后关掉进程。参考http://blog.csdn.net/debug__boy/article/details/8432879提供新的解决方案，国外大神的文章http://huddledmasses.org/setting-windows-internet-connection-proxy-from-c/：代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace IEProxyManagment
{

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);
}
}

#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);
}
}

　　UnsetProxy方法为取消代理设置，SetProxy(string strProxy, string exceptions)方法为设置指定代理。

　　以下是我做的一个可以动态修改代理的Winform程序，备忘下载。