I am having a problem marshaling data between managed and unmanaged code. So I need to inspect the data at the byte level. What I need to do is store a number, say 8 into a 4-byte integer then copy it to an array bytArray(4) and compare those bytes with other data. I also need to set up the same array and copy it to an integer variable.
View 2 RepliesI am trying to develop a dll in VisualStudio2005 in vb.net that will communicate with a spectrometer attached to the USB port of the computer.Now the dll exists in C++ and it works like a charm. It is unmanaged code.Now if I try to translate this code in VB.net (because our app is in VB and my boss wants it in VB for maintainability) I have problems.
First of all, I am trying to create a file to open that port. The code in C++ looks like below and it works. Needles to say I tried to call the C++ dll from our app and it works. If I call the vb dll it doesn't. It gives me "access denied" no matter what I tried. I am not sure if my CreateFile is wrong or it's .net. I read somewhere that I need a manifest file included in the dll? Has anyone experience something like this? Why would i get "ACCESS DENIED" all the time?
// close and clear current stuff
ClosePort();
swprintf( sDevice, L"\\?\usb#vid_0765&pid_%s#******#{%s}", Device, PRIVATE_IID_STR );
[code].....
I need to write a DLL in C that is used a plugin for an existing application.The DLL has to be compiled by the Visual Studio 2008 compiler with the following options.[code]It's then linked to applications library's.What it actually needs to do and what's causing me the issues is that within one of the methods it needs to pull data from a sql server 2008 r2. From what I've seen today you wouldn't be able to do this directly in C as SQL Server past 2005 is designed to communicate with CLR languages( C#, C++, VB.Net).It was suggested that I handle all the database communication with a VB.Net dll and then call said function from within the C dll. Most of what I've found on the topic of calling managed dll's from unmanaged code has talked about pinvoke or com wrappers and mainly from the perspective of c++.
View 2 RepliesI am trying to get some data from a C Dll via a structure and I am getting incorrect values back. I tried a couple of examples I found but they do not work. Since I do not know the proper way. I do not know how to fix it. Can anyone give me any advice, hints, redirection or any assistance what-so-ever. I've been struggling with this for weeks.
View 3 Repliesdebug the managed / unmanaged boundry environment: VS2010 on Win7 64bit
View 1 RepliesI am having trouble converting some code from VB6 to VB.NET (I don't have as much experience with .NET). When I run the 'Select function (from the WS2_32.dll library) in .NET, using the same parameters as the VB6 program, it returns a result of -1 (indicating an error). I think the error may be related to an upgrade comment I saw about marshalling, but I was not sure what I needed to do to declare the function differently. Here is the code that I believe is related to the problem (including the upgrade warnings from Visual Studios):
<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> Private Structure FD_SET
Dim fd_count As Integer
<VBFixedArray(FD_SETSIZE)> Dim fd_array() As Integer
Public Sub Initialize()
[code]....
how to open a "data link properties" dialog using manged code
View 1 RepliesIs it possible to start another EXE in Managed Code? At this time, all I can do is use:
System.Diagnostics.Process.Start(exeName)
Is there another way to call another EXE within the same project?
I have an application which has been succesfully installed on a number of different client machines.
The problem I now have is that I have been asked to allow third party applications, possibly written in a non .net language set to plug into my application and execute some of the code. Just a handfull of properties and half a dozen methods.
Now I can wrap up these properties/methods, make them public and have them in their own project which will be part of my solution but I have no idea where to go from here.
How do I make this portion of my application accessible to a third party application written in unmanaged code ?
I have a .Net application (VB in particular, although I would this to be as language agnostic as possible) that uses a COM object (made in C++). I need to implement a event in COM that passes a char array from C++ to .Net. I guess I need to convert the array to a managed array; How can I do this?
View 2 RepliesHow to identify the x64 or x86 of the OS and a Process in managed code?
View 1 RepliesWhat should be the VB signature for the unmanaged function void PopulateBSTR(BSTR outstring)?The function PopulateBSTR does a SysAllocString and populates the string. Note the unmanagaed signature has the argument BSTR and not BSTR*. I can marshal the BSTR string using IntPtr signature when the C++ signature has BSTR* as the argument.
(The unmanaged code is an external dll which I cannot modify but I need to use.)
First of all; I'm completely new to VB.
Pass a string array from Visual Basic Express 2008 to unmanaged code in a Dll.The array is Dimmed as in DIM myArray(11) as String
I'm developing the dll myself using Powerbasic.
The dll expect a 4 bytes pointer to a safearray's handle. As far as I have understood it; the array's string elements must be passed in ANSI format. The code in the dll will then use OLE Api to get the LBound and Ubound of the array and the address of the first element in array.
We have a VB.NET program that needs to periodically call a function in an external, unmanaged DLL to communicate with our legacy application. We are having a problem with the application (seemingly) randomly not being able to find the DLL with the unmanaged code. Currently we use DECLARE FUNCTION blah LIB for the unmanaged code. Would it be better/more reliable to use DllImportAttribute instead? Or am I missing something else?
View 1 RepliesIn my managed VB.NET code, I am able to write a file out to my desktop. Although, the statically referenced unmanaged code is unable to. I have hunted all over MSDN to find out how I can elevate the security permissions for this library method, but am unableto find anything.I declare the method as...Declare Sub WriteFile Lib "DataLog.dll" (ByVal fileName As String)Although, it throws an exception due to being forbidden from writing to the desktop. Is there an attribute
View 7 Repliesi am using directx in my form but my program cant load managed direct(i instal Microsoft SDK V 9.29.1962.0) AND SHOW THIS ERROR:
Unhandled exception has occurred in your application. If you click Continue, the application will ignore this error and attempt to continue. If you click Quit, the application will close immediately.Mixed mode assembly is built against version V1.1.4322" of the runtime and cannot be loaded in the 4.0 runtime without additional configuration information.
figure out a way to link datagridviews to other controls like a combobox, list view or even another datagridviewBecause much of the code is managed by the IDE, I was expecting an IDE approach to linking controls. Is this the case or do I have to modify the generated code to do what I want.An example would be to use a combobox to limit the number of entries in a datagridview etc
View 2 RepliesWhat is marshalling in vb.net
View 1 RepliesTrying to read the OBJECTDESCRIPTOR on the clipboard. Almost get it. My guess I don't know how to Marshall the structure. I definetly don't know how to handle: ..."null-terminated string whose offset in bytes is specified in the dwSrcOfCopy "Getting this returned variable length string is what I need help with.
Start with this
typedef struct tagOBJECTDESCRIPTOR {
ULONG cbSize;
CLSID clsid;
DWORD dwDrawAspect;
[code]....
I'm trying to interact with the Windows SDK to control a Portable Media Device, and am running into problems correctly marshalling variables to the types expected by the SDK DLLs.I have the following code.
View 2 RepliesI'm experiencing a problem with the following c-structure:
typedef struct tagTEXTUREPROP
{
DWORD dwSize;
[Code].....
The Marshal.SizeOf obviously calculates a size of 76 and it works with the DLL function, but it leaves me with some bad feelings.
i need to pass commands through a C++ dll to vb.net and the other way around. is there some code that needs to be in the C++ dll to make it work? im not good at C++ at all,
View 5 RepliesWhat's the advantages of the above types of dll? Is there any other type?
View 1 RepliesI am writing classes in VB.Net (both managed). The main class "A" creates an instance of "B". Class "B" must call a method of Class "A". I need to know two things (syntax, etc...):
1. How does class "A" tell class "B" what method to call?
2. How does class "B" call the method?
The method must pass back an array of Shorts (in this particular example), either as a return value, or as a ByRef argument.I don't want to use an event if I don't have to. The execution is timing critical. (I assume event handling involves a lot of overhead by the operating system, but I may be wrong.)
im trying to make a simple wrapper for lua. The only problem so far is that lua only accepts a method in a specific format.Delegate Function LuaC Function(ByVal lua_state As IntPtr) As Integer..That is how lua wants the method to look like. So it only accepts a function that looks like this: [code]
View 2 RepliesI created a vb.net dll called "WSdll.dll".I compiled it, created a type library (tlb), and registered it globally(gacutil)..It includes a file called wsutils.vb, which includes a namespace called "wsutils".In the namespace, there's an interface (with attribute) called "IWSconnection", and a class called "WSconnection".The interface and class are public, as are all methods and properties.[code]...
View 2 RepliesI have absolutely no background on programming in C (or any other unmanaged languages for that matter) yet I would like to use the GetBestInterface function from the IP Helper API in my .NET application. I tried to understand how P/invoke calls can be used to make calls to native methods, but there are many things that just don't make sense to me (like how types in managed code map to unmanaged types).
Is there an alternative function somewhere hidden in the System.Net namespace that does roughly the same thing? Or could I write my own alternative using existing base classes combined with some magic? Because that's basically what it seems to me: magic. There is no real explanation for how the method accomplishes what it does as far as I can tell...
I just discovered the LocalEndPoint property on the System.Net.Sockets.Socket class which I think could be quite useful in this. To my understanding it will do the best-interface-picking on my behalf and I'll just need to get the NIC that corresponds to the local endpoint.
I am having a very strange memory leak that seems related to databinding. It is very hard to reproduce, so I won't post any code here to do so, but will just describe the problem.We have data entry forms which have controls which bind to custom business objects through a BindingSource object.
View 7 RepliesIs there anyway to create an OS or Managed thread, so that it can never be interrupted. Thread/Process priorities are not enough.
View 2 RepliesI have an application written in .NET 4.0 that needs to load in memory a native DLL (written C). At the moment I am using a P/Invoke call to LoadLibrary passing the path where the DLL is located. This works, but due to the fact that this DLL comes from a DB, I would like to know if it is possible loading it through a stream, avoiding then the necessity to store the DLL somewhere in the filesystem.
View 2 Replies