Charles,
As Stephen stated, there is not bit field access in C# or VB.NET per se.
There is however a System.Collections.BitVector32 class that gives you
access to bit fields.
When I implemented the DCB structure in VB.NET I defined Flags as a Private
BitVector32. Then used Property procedures that extracted the individual
values, using the methods of BitVector32.
Public enum RtsControl As Byte
Disable = 0
Enable = 1
Handshake = 2
Toggle = 3
End Enum
Public Structure DBC
...
Private Flags As BitVector32
...
Private Shared Readonly m_fBinary As Integer
Private Shared Readonly m_Parity As Integer
...
Private Shared Readonly m_fRtsControl As BitVector32.Section
...
Shared Sub New()
' create boolean masks
m_fBinary = BitVector32.CreateMask()
...
m_fParity = BitVector32.CreateMask(m_fBinary)
...
' create section masks
Dim previousSection As BitVector32.Section
previousSection = BitVector32.CreateSection(1)
...
m_fRtsControl = BitVector32.CreateSection(3,
previousSection)
...
End Sub
Public Property Binary As Boolean
Get
Return Flags.Item(m_fBinary)
End Get
Set(ByVal value As Boolean)
Flags.Item(m_fBinary) = value
End Set
End Property
...
Public Property RtsControl As RtsControl
Get
Return CType(Flags.Item(m_fRtsControl), RtsControl)
End Get
Set(ByVal value As RtsControl)
Flags.Item(m_fRtsControl) = value
End Set
End Property
...
End Structure
BitVector32 is marshaled as an Integer (DWORD) so you can use them
interchangeably.
I made Flags Private as its an implementation detail.
The property procedures expose the flags as the respective types, For
example RtsControl & DtrControl as enums with valid values, others as
Boolean. I had to change a couple names as there is a field & a flag
(ErrorChar).
For the BitVector32 masks I had to make two passes, once for the boolean
values, then a second one for the section (enum) values.
Using the BitVector32 class simplified my property procedures at the
"expense" of a little extra setup (the shared constructor).
I have not posted my class on got dot net yet, as I am still working on
making the WaitEvent async.
Hope this helps
Jay
"Charles Law" <bl**@thingummy.com> wrote in message
news:%2****************@TK2MSFTNGP10.phx.gbl...
I have the following structure (for example) that I wish to convert for
use in VB.NET. What would be the best way to do it? Ideally, it would convert
directly to allow access to the bit fields in the same way as in C++, but
I cannot see any mention of bit field declarations in VB.NET.
<structure>
typedef struct _DCB {
DWORD DCBlength;
DWORD BaudRate;
DWORD fBinary :1;
DWORD fParity :1;
DWORD fOutxCtsFlow :1;
DWORD fOutxDsrFlow :1;
DWORD fDtrControl :2;
DWORD fDsrSensitivity :1;
DWORD fTXContinueOnXoff :1;
DWORD fOutX :1;
DWORD fInX :1;
DWORD fErrorChar :1;
DWORD fNull :1;
DWORD fRtsControl :2;
DWORD fAbortOnError :1;
DWORD fDummy2 :17;
WORD wReserved;
WORD XonLim;
WORD XoffLim;
BYTE ByteSize;
BYTE Parity;
BYTE StopBits;
char XonChar;
char XoffChar;
char ErrorChar;
char EofChar;
char EvtChar;
WORD wReserved1;
} DCB;
</structure>
TIA
Charles
