Function delegate from a procedure address

[Bucky]

Ive been trying to replicate some C++ code in VB.NET. The
C++ code gets a function address by using GetProcAddress, then
casts that into a delegate that then calls a callback function in
the code. So far I can correctly get the procedure address into
an IntPtr variable, but now Im trying to create an instance of a
function delegate based on this address. DirectCast wont take
a value type (the procedure address) as a first parameter, so how
else might I cast it? The solution may lie in the Marshal object,
but I cannot find it.

Heres the C++ code:

// Heres the delegate declaration
typedef ULONG (*GetAttachedDevicesProc) (ULONG* pDeviceCount, PTCHAR pBuffer, ULONG* pBufferSize);

// And the instance of that delegate
static GetAttachedDevicesProc	 gGetAttachedDevices;

// This is the tricky part, it casts the proc address to an actual delegate
gGetAttachedDevices = (GetAttachedDevicesProc) ::GetProcAddress (fgUSBLib, "PalmUsbGetAttachedDevices")

And the VB.NET code I have so far:

 The delegate:
Private Delegate Function GetAttachedDevicesDelegate(ByVal deviceCount As Integer, ByVal buffer As String, ByVal bufferSize As Integer) As Integer

 Getting the procedure address:
procAddress = New IntPtr(GetProcAddress(moduleHandle.ToInt32(), "PalmUsbGetAttachedDevices"))

 Now how do I make a new instance of GetAttachedDevicesDelegate based on the address?

 

[Volte]

Perhaps you should make the return type of GetProcAddress a Delegate type.

 

[Bucky]

Oooh, good idea... unfortunately it didnt work. An error was thrown:
"System.ArgumentException - Function pointer was not created
by a Delegate."

So it looks like its closer than before...

 

[Volte]

Try here: http://staff.develop.com/woodring/dotnet/#getprocaddress