Windows Mobile上的GPRS连接(基于TcpClient)

 

Windows Mobile上的GPRS连接(基于TcpClient)

 

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);
        }


        
private static bool Release(string urlStr, bool removeNode)
        
{
            
bool res = true;
            IntPtr ph 
= IntPtr.Zero;
            
if (ht[urlStr] == null)
                
return true;
            ph 
= (IntPtr)ht[urlStr];
            
if (ConnMgrReleaseConnection(ph, 1!= S_OK)
                res 
= false;
            CloseHandle(ph);
            
if (removeNode)
                ht.Remove(urlStr);
            
return res;
        }


        
public static void ReleaseAll()
        
{
           
foreach(DictionaryEntry de in ht)
           
{
               Release((
string)de.Key, false);
           }

           ht.Clear();
        }


        [StructLayout(LayoutKind.Sequential)]
        
public struct ConnectionInfo
        
{
            
public uint cbSize;
            
public uint dwParams;
            
public uint dwFlags;
            
public uint dwPriority;
            
public int bExclusive;
            
public int bDisabled;
            
public Guid guidDestNet;
            
public IntPtr hWnd;
            
public uint uMsg;
            
public uint lParam;
            
public uint ulMaxCost;
            
public uint ulMinRcvBw;
            
public uint ulMaxConnLatency;
        }


        [DllImport(
"cellcore.dll")]
        
private static extern int ConnMgrMapURL(string pwszURL, ref Guid pguid, IntPtr pdwIndex);

        [DllImport(
"cellcore.dll")]
        
private static extern int ConnMgrEstablishConnectionSync(ref ConnectionInfo ci, ref IntPtr phConnection, uint dwTimeout, ref uint pdwStatus);

        [DllImport(
"cellcore.dll")]
        
private static extern IntPtr ConnMgrApiReadyEvent();

        [DllImport(
"cellcore.dll")]
        
private static extern int ConnMgrReleaseConnection(IntPtr hConnection, int bCache);

        [DllImport(
"coredll.dll")]
        
private static extern int CloseHandle(IntPtr hObject);
    }

使用GPRSConnection class的时候, 先调用Setup方法创建连接,见以下代码:

 

 

        public void DoTcpConnection()
        
{
            
string url = "www.msn.com";
            
bool res = GPRSConnection.Setup("http://" + url + "/");
            
if (res)
            
{
                TcpClient tc 
= new TcpClient(url, 80);
                NetworkStream ns 
= tc.GetStream();
                
byte[] buf = new byte[100];
                ns.Write(buf, 
0100);
                tc.Client.Shutdown(SocketShutdown.Both);
                ns.Close();
                tc.Close();
                MessageBox.Show(
"Wrote 100 bytes");
            }

            
else
            
{
                MessageBox.Show(
"Connection establishment failed");
            }

        }

Enjoy,

 

黄季冬

posted on 2008-08-15 21:16 J.D Huang 阅读(...) 评论(...) 编辑 收藏

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