C# Definitions:

[StructLayout(LayoutKind.Sequential,CharSet = CharSet.Auto)]
struct RASDIALPARAMS {
   public int  dwSize;
   [MarshalAs(UnmanagedType.ByValTStr, SizeConst = Constants.RAS_MaxEntryName + 1)]
   public string szEntryName;
   [MarshalAs(UnmanagedType.ByValTStr, SizeConst = Constants.RAS_MaxPhoneNumber + 1)]
   public string szPhoneNumber;
   [MarshalAs(UnmanagedType.ByValTStr, SizeConst = Constants.RAS_MaxCallbackNumber + 1)]
   public string szCallbackNumber;
   [MarshalAs(UnmanagedType.ByValTStr, SizeConst = Constants.UsernameLength + 1)]
   public string szUserName;
   [MarshalAs(UnmanagedType.ByValTStr, SizeConst = Constants.PasswordLength + 1)]
   public string szPassword;
   [MarshalAs(UnmanagedType.ByValTStr, SizeConst = Constants.DomainLength + 1)]
   public string szDomain;
   public uint    dwSubEntry;
   public IntPtr dwCallbackId;
}

VB Definition:

Structure RASDIALPARAMS
   Public TODO
End Structure

User-Defined Field Types:

None.

Notes:

Most RAS specific constants are documented at :

http://www.pinvoke.net/default.aspx/Constants.ras

Other constants are:

const int UsernameLength = 256;

const int PasswordLength = 256;

const int DomainLength = 15;

Alternative Managed API:

http://www.codeplex.com/DotRas