Alex Mogurenko`s Blog

If we will ask somebody experienced questions like:”What should we use to establish dial up connection on Windows”, i`m totally sure that 90% of asked will answer use RAS library!

If some somebody will ask me what do to establish GPRS connection on Windows Mobile i answer use Connection Manager API, but there is nothing regarding Connection Manager API on Windows CE, but we can use RAS API!

If you developing on C++ or C thats not a problem, but what to do if your project on C#? I googled and found that opennet cf got ras components, but it aint free(!), so we need to create our own

using System;
using System.Text;
using System.Runtime.InteropServices;

namespace CERas
{
/// <summary>
/// CERAS
/// </summary>
public class CERAS : IDisposable
{
#region Constants
private const int ENTRY_SIZE = 1464;
#endregion

#region P/Invoke
[DllImport("coredll.dll")]
public static extern uint RasDial(
IntPtr dialExtensions,
IntPtr phoneBookPath,
IntPtr rasDialParam,
uint notifierType,
IntPtr notifier,
ref IntPtr pRasConn);

[DllImport("coredll.dll")]
public static extern uint RasHangUp(IntPtr pRasConn);
#endregion

#region Private Declarations
private IntPtr rasConn_ = IntPtr.Zero; //Connection Handle
private uint result_ = 0;
private IntPtr rasEntry_ = IntPtr.Zero; //Entry Container
private string connName_ = ""; //connection name
private string userName_ = ""; //user name (could be empty string)
private string password_ = ""; // password (could be empty string)
#endregion

#region Properties
//property, sets or gets connection name
public string ConnectionName
{
get
{
return connName_;
}
set
{
if (value != connName_)
{
connName_ = value;
}
}
}

//property, sets or gets connection login
public string Login
{
get
{
return userName_;
}

set
{
if (value != userName_)
{
userName_ = value;
}
}
}

//property, sets or gets connection password
public string Password
{
get
{
return password_;
}
set
{
if (value != password_)
{
password_ = value;
}
}
}

//property, checks if connection established
public bool Established
{
get
{
return ((rasConn_ != IntPtr.Zero) && (result_ == 0));
}
}
#endregion

#region Public Methods
//Constructor
public CERAS()
{
rasConn_ = IntPtr.Zero;
result_ = 0;
rasEntry_ = Marshal.AllocHGlobal(ENTRY_SIZE); //Allocating 1464 bytes (size of Entry structure)
if (rasEntry_ == IntPtr.Zero)
{
throw new Exception("Error cannot get Allocate memory");
}
}

// Destructor
public void Dispose()
{
Marshal.FreeHGlobal(rasEntry_); //Free allocated memory
}

//Establishing connection, it will block thread that called this method
public bool Connect()
{
if (rasConn_ != IntPtr.Zero)
{
Disconnect();
}

FillEntry();
try
{
result_ = RasDial(IntPtr.Zero, IntPtr.Zero, rasEntry_, 0, IntPtr.Zero, ref rasConn_);
}
catch
{
//exception
}

if (result_ != 0)
{
Disconnect(); //we need call disconnect even if connection was not established
return false;
}
return true;
}

//Closing internet connection
public void Disconnect()
{
if (rasConn_ != IntPtr.Zero)
{
RasHangUp(rasConn_);
rasConn_ = IntPtr.Zero;
result_ = 0;
System.Threading.Thread.Sleep(3000); //read msdn, it says that we need wail like 3 seconds to release connection(!)
}
else
{
result_ = 0;
}
}
#endregion

#region Private Methods
//Clearing Entry Structure
private void ClearPtr()
{
//I`m totally sure that there should be easier way
for (int i = 0; i < ENTRY_SIZE; i++)
{
Marshal.WriteByte((IntPtr)(rasEntry_.ToInt32() + i), 0);
}
}

//Filling Entry structure
private void FillEntry()
{
ClearPtr();
IntPtr pCurrent = rasEntry_;
Marshal.WriteInt32(pCurrent, ENTRY_SIZE);

pCurrent = (IntPtr)(pCurrent.ToInt32() + 4);
foreach (byte b in Encoding.Unicode.GetBytes(connName_))
{
Marshal.WriteByte(pCurrent, b);
pCurrent = (IntPtr)(pCurrent.ToInt32() + 1);
}

pCurrent = (IntPtr)(rasEntry_.ToInt32() + 0x192);
foreach (byte b in Encoding.Unicode.GetBytes(userName_))
{
Marshal.WriteByte(pCurrent, b);
pCurrent = (IntPtr)(pCurrent.ToInt32() + 1);
}

pCurrent = (IntPtr)(rasEntry_.ToInt32() + 0x394);
foreach (byte b in Encoding.Unicode.GetBytes(password_))
{
Marshal.WriteByte(pCurrent, b);
pCurrent = (IntPtr)(pCurrent.ToInt32() + 1);
}
}
#endregion
}
}

Yau can download sources from here

BTW it should work on win mobile too

Filed under: Programming