在有线的连接和WIFI都不可用的时候, .NET CF的HttpWebRequest会由于web requests/web services 而自动设置GPRS连接。所以实际上当你发起一个Web请求或者连接Webservice的时候，并不需要开发者编码处理GPRS的连接问题。不过对于更低层的通信，如使用TcpClient 和 UdpClient的时候，则需要为咩使用 Connection Manager API来建立和释放连接。 (本文英文原文见：http://blogs.msdn.com/anthonywong/archive/2006/03/13/550686.aspx)
以下托管类是对Connection Manager API的封装
public class GPRSConnection
{
const int S_OK = 0;
const uint CONNMGR_PARAM_GUIDDESTNET = 0x1;
const uint CONNMGR_FLAG_PROXY_HTTP = 0x1;
const uint CONNMGR_PRIORITY_USERINTERACTIVE = 0x08000;
const uint INFINITE = 0xffffffff;
const uint CONNMGR_STATUS_CONNECTED = 0x10;
static Hashtable ht = new Hashtable();
static GPRSConnection()
{
ManualResetEvent mre = new ManualResetEvent(false);
mre.Handle = ConnMgrApiReadyEvent();
mre.WaitOne();
CloseHandle(mre.Handle);
}
~GPRSConnection()
{
ReleaseAll();
}
public static bool Setup(Uri url)
{
return Setup(url.ToString());
}
public static bool Setup(string urlStr)
{
ConnectionInfo ci = new ConnectionInfo();
IntPtr phConnection = IntPtr.Zero;
uint status = 0;
if (ht[urlStr] != null)
return true;
if (ConnMgrMapURL(urlStr, ref ci.guidDestNet, IntPtr.Zero) != S_OK)
return false;
ci.cbSize = (uint) Marshal.SizeOf(ci);
ci.dwParams = CONNMGR_PARAM_GUIDDESTNET;
ci.dwFlags = CONNMGR_FLAG_PROXY_HTTP;
ci.dwPriority = CONNMGR_PRIORITY_USERINTERACTIVE;
ci.bExclusive = 0;
ci.bDisabled = 0;
ci.hWnd = IntPtr.Zero;
ci.uMsg = 0;
ci.lParam = 0;
if (ConnMgrEstablishConnectionSync(ref ci, ref phConnection, INFINITE, ref status) != S_OK &&
status != CONNMGR_STATUS_CONNECTED)
return false;
ht[urlStr] = phConnection;
return true;
}
public static bool Release(Uri url)
{
return Release(url.ToString());
}
public static bool Release(string urlStr)
{
return Release(urlStr, true);
}