Adapting a DLL to VB.NET, using PINVOKE
-
Hi again, in normal situations, you don't need to go into the internals of events, i.e. I don't expect you would need Delegate.Combine at all. In normal circumstances, all the code you would need is what can be found in the MSDN example here[^]. There are three parts: 1. event declaration, with
eventkeyword 2. event set-up, based onAddHandler3. event processing, which looks like a regular method you have to provide. :)Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
If you want my opinion or comment, ask in a forum or on my profile page; I will not participate in frackin' Q&A
I am looking into it right now, hopefully I will be able to rewrite the functionality of this part of code using normal VB.net syntax as shown on MSDN. That is the only remaining error by the way, I have fixed all the other errors except for this one concerning events and delegates.
-
I am trying to dissasemble a .net dll via reflector, one that has been in use in our company for ages, as practice. My future task will be to produce similar dll-a that are com interoparabile and activex compliant. I am doing this in VB.net, and I have already been told that this is a big no-no, dlls of this sort are supposed to be made with C++ people say. I would guess that they are stating this because C++ uses pointers (which are heavily used in many DLLs when it comes to pointing to a pointer - i.e. memory location that holds particular relevant info). Be as it may, I wish to proceed building this dll in vb.net to see how far I can get before I am forced to switch to C++ or C#... I have already made a lot of fixes to the code, thus reducing the number of errors from over 120 to 30 which is, I would guess, a good start, but now I am facing several errors that are above my level of knowledge (I am a beginner after all) and I would like to get some information from people who are more experienced than me. * First problem I encountered is the following: (this is an excerpt of code dealing with events that happen on a SERIAL port).
Public Custom Event OnCTS As OnCTS
AddHandler(ByVal value As OnCTS)
Me.OnCTS = DirectCast(Delegate.Combine(DirectCast(Me.OnCTS, Delegate), DirectCast(value, Delegate)), OnCTS)
End AddHandler
RemoveHandler(ByVal value As OnCTS)
Me.OnCTS = DirectCast(Delegate.Remove(DirectCast(Me.OnCTS, Delegate), DirectCast(value, Delegate)), OnCTS)
End RemoveHandler
End EventThis is what the reflector did for me, unfortunately the first "DELEGATE" keyword after DirectCast has an error attached to it: "expression expected". I have tried using "raiseevent" instead but if I use that, another piece of code later will not work. Currently I have this:
Public Custom Event OnCTS As OnCTS
AddHandler(ByVal value As OnCTS)End AddHandler RaiseEvent() End RaiseEvent RemoveHandler() End RemoveHandler End EventBut I do not know the proper syntax for this nor where to begin. I have only recently started doing event driven code. * A similar error (DELEGATE keyword, "keyword does not name a type") happens in this line of code:
Me.parent.Invoke(DirectCast(New EventHandler(AddressOf callback.ToMainThread), Delegate))
* The third problem is in this line of code
Dim numRef As Byte*
Fixed numRef = bufferI have this thing that puzzles me. :omg: I suppose that fixed means that garbage collector isnt allowed anywhere near the memory location to prevent accidental removal. That I can do in VB.net. :thumbsup: On the other hand I have no idea what Byte* is, seems to me its a pointer, what I do know from debugging is that it seems to retain only the first element in buffer (which is an array of 1023 I think, irrelevant at this point). Does the pointer point only to the first element? :confused: So if you store 1023 bytes in byte* it retains only the first byte? Please help ;) Added more info at 12:00 The next line of code is the following;
flag2 = Win32.ReadFile(Me.m_handle, numRef, 50, (numBytesRead), AddressOf overlapped)
numref in this case is taken from the line before and hence flag2 returns boolean true. Interesting thing is, in my patchwork code I use the following
Dim flag2 As Boolean = False
Dim numRef As Byte() = Nothing
numBytesRead = Nothing
numRef = buffer
flag2 = False
flag2 = Win32Serijski.ReadFile(Me.m_handle, numRef, 50, numBytesRead, overl)And in contrast to the original code, my flag2 ALWAYS returns TRUE, while in the original code it returns true only if theres NEW data in the buffer. :confused: