Hi, I had to do a similar thing on the project i'm working on, but instead of using a DB, I just wrote the 'structure' of the tree to an XML file. The top-level elements represented parent tree nodes, and any child nodes of the parent nodes were written as child elements. You could then just parse the XML file, creating TreeNodes as you go through the different XML elements. Of course it depends on how much information you need to store. For me, all I really needed was the text of the nodes and the hierarchal structure. I hope this helps buddy! cheeze

Hi, I'm trying to dynamically load an unmanaged dll and call a function within it from a managed C++ app. I've managed to do this in an unmanaged C++ app, using calls to LoadLibrary and GetProcAdddress, but don't know what to do in the .NET version. I know there's P/Invoke, but with that the library has to be declared at compile-time, and I won't know the (unmanaged) library until run-time. So i guess the question is how can I use the LoadLibrary and GetProcAddress functions in managed C++ (again not using P/Invoke, as the library won't be known until run-time)? Thanks for your help Cheeze

Thanks for your help guys, Sorry S Pandian, I should've been clearer - I am actually able to use the COM object fine, only when I tried accessing it in another thread did I have this problem. Mike, I think you hit the nail on the head! I was creating the object in another thread, and then trying to access it later on, once that thread had exited. But without using another thread, everything works fine. Cheers guys, Shehzad

Hi All, I'm accessing a COM object from my .NET application, but I keep on getting the following exception: "COM object that has been separated from its underlying RCW can not be used" Does anyone know how this exception can come about? I'd appreciate any thoughts, thanks. Shehzad

Hello everyone, I need to write a DCOM server object in C#. Is this possible? Can I just write a C# Remoting object and then expose this as a COM object, or will this not work because the object needs to be accessed remotely? Any help would be greatly appreciated! Thanks, Shehzad

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Judah Himango wrote:

As far as the error, there's no way that we can know. Can you show us the function signature (both native COM and .NET wrapper) for that function that's causing the error? Sure: in 'original COM dll' (shown in VB6): Public Sub ConnectProjectEx(_ByVal DomainName As String,_ByVal ProjectName As String,_ByVal UserName As String,_ByVal UserName As String,_Optional ByVal Password As String = " "_) and in the interop wrapper (using ildasm): .method public hidebysig newslot virtual instance void ConnectProjectEx([in] string marshal( bstr) DomainName, [in] string marshal( bstr) ProjectName, [in] string marshal( bstr) UserName, [in][opt] string marshal( bstr) Password) runtime managed internalcall When I pass to this function an invalid username or password, it actually throws an exception, saying 'The user so and so does not exist'. However, when I give it a correct user, it throws the application error I mentioned before - it seems that it gets further in the dll function, and then fails, and since I can't see the actual code in the COM dll (since it's third party), I don't know what to do! Thanks for your help. Shehzad

Hello, I'm using a third party COM dll, which I've referenced in my C# project. However, when I call a certain function in it, it throws an error message saying "The instruction at 0x10153c89 referenced memory at 0x0751629c. The memory could not be 'read'" and then the application terminates. Is this most likely to be an error in the COM dll, or does anyone else have any other ideas on what the problem may be? When Visual Studio generates the interop assembly for the COM dll and places it in your build output directory, how does it 'route' the function calls to the actual COM dll it wraps, or is this information contained within the interop assembly itself? Thanks for your time and help Shehzad

Hello all, Does anyone know of any way of calling functions in a VB6 exe, from code in C#? Is this even possble? I don't know much (if anything!) about VB6 so I'm a bit confused. I've managed to call functions in a VB6 dll, but is the same thing possible with exe's too? As always, any help at all would be greatly appreciated! Thanks Shehzad

Hi, Is there any way to register a COM dll at run-time, from the code, for example by a certain win32 API call? Thanks for the help! Shehzad

Hi, Could someone please tell me what is the best way to late bind to COM dlls? I'm basically developing an application that loads specified dlls and then runs certain functions contained in those dlls. The problem is that I don't know the libraries to load until runtime, so I can't really use tlbimp. I know it is possible to use tlbimp at runtime (using TypeLibConverter) but this creates new names for the functions in the dll, so it may not be such a good idea... Any help would be greatly appreciated, thanks! Shehzad

Thanks a lot for your help guys, your advice seems to have done the trick!! Thank you!:-D

Hi, I'm starting a process with ProcessStartInfo, setting the 'Arguments' property to a filepath to the file I want to start the process with. However, the process I start is complaining about the filepath - since the filepath has spaces in it, it only seems to pass to the process the filepath upto the first space, and then ignores the rest. The process I'm trying to start is regsvr32.exe and the argument is a filepath to a dll I want to register. Could anyone please help me? Thanks a lot, Shehzad

Is there anyway to do this at runtime?

Hi, Just one quick question: Do you have to register COM DLLs first using regsvr32 before you can create any instances of classes in the COM DLL? If so, is there anyway around this? Any help would be much appreciated! Thanks!

I had a similar function that returned a string from a C++ dll. Try declaring a global char array in your dll and then copy the string into the array, as below: // global char array char szReturn[MAX_PATH]; BOOL APIENTRY DllMain( HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved ) { return TRUE; } __declspec(dllexport) LPCTSTR Test() { lstrcpy(szReturn,"success!"); return szReturn; } Hope that helps ;)

Hi, I'm trying to access functions residing in a VB6 exe. Does anyone know of a way to access these functions in C#.NET? Thanks, Shehzad