Pass String Array To Unmanaged Code In A Dll?
May 10, 2009
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.
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Feb 24, 2009
I am writing an OPC Client in VB.NET (2008) and I am using an OPC wrapper from Graybox. I am having some problems with the data types. I have an Array of String that contains all of the OPC Items that I wish to read from the OPC Server. When I attempt to use the Array of String, Option Strict causes the following compile error message:Error 5 Option Strict On disallows narrowing from type 'System.Array' to type '1-dimensional array of String' in copying the value of 'ByRef' parameter 'ItemIDs' back to the matching argument. How do I pass the Item ID's (all strings) in an array?
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Apr 7, 2011
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?
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May 5, 2009
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 ?
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Dec 15, 2010
I have a structure in VB.NET that has a dynamic array of double as a parameter. I am passing an array of structure (GElement) to a C++ DLL. I tried converting my array of GElement into a block of unmanaged memory, it works in VB.NET but crashes in my C++ DLL. I get the same error just trying to simply pass an array of GElement to my DLL instead of a Intptr.
Here is the error
0xC0000005: Access violation reading location 0x00000004
Here is my function and structure in the DLL:
void _stdcall TestGElement(GElement* ge,long& nbge){
nbge=5;
} struct GElement {
double Step2D;
double Step3D ;
[Code] .....
I know it is easier if the array inside the structure as an already defined constant size but that can't be the case here...
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May 23, 2011
What 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.)
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Sep 19, 2010
I 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].....
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May 30, 2012
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++.
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Feb 19, 2010
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.
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Nov 2, 2011
I'm calling unmanaged C++ Dll function from VB.Net project by usin dllimport attribute like this;
<DllImport("Injection.dll", CallingConvention:=CallingConvention.Cdecl)> _
Private Shared Sub Injector(ByRef Client As String, ByRef Dll As String)
End Sub
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Aug 29, 2011
I got this DLL functions explained in C++ as below :Void GetResultData(int pIndex,char pStrData[100][255], double pDoubleData[100])
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Jun 3, 2011
Right now I am using this code on client side.
[Code]...
The values for the hidden fields are already set. I want these value to open a window, in which the fields will be already filled using the values passed by this page. This code is working fine on Internet Explorer, but not on other browsers. Moreover, when I don't pass any value and just open the required window, it works on all browsers.
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Aug 20, 2010
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?
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Apr 25, 2011
In 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
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Mar 11, 2010
I have written my own function, which in C would be declared like this, using standard Win32 calling conventions:int Thing( char * command, char * buffer, int * BufSize);I have the following amount of VB figured out, which should import the dll and call this function, wrapping it up to make it easy to call Thing("CommandHere",GetDataBackHere).UPDATE:This code is now a working solution, as shown here:
Imports Microsoft.VisualBasic
Imports System.Runtime.InteropServices
Imports System
Imports System.Text
[Code]...
Updates: I got the code to build by following the help received here, and then I had forgot the As Return Type (which got me a MarshalDirectiveException PInvokeRestriction). Then I had an assertion failure inside my DLL, which lead to an SEHException. Once fixed, this works BEAUTIFULLY. There are newsgroups where people are saying this can not be done, that VB only loads managed dll assemblies (which I guess is the normal thing most VB users are used to).
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Jun 19, 2009
This code was working consistently, but now...This code works on the first pass.Then second pass it just hangs on Code:Dim tcpClient As TcpClient = tcpListener.AcceptTcpClient() for about 2 minutesThen the code will fork for another pass, then fail.....
Code:Imports SystemImports System.TextImports System.Collections.GenericImports System.XmlImports System.Xml.LinqImports System.Net.Sockets
[CODE]....
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Aug 9, 2010
In VS2010 I'm encountering a PInvokeStackImbalance error when I call an unmanaged C function that takes a string argument. This only happens in VS2010 (works fine in earlier versions of vs). I know the MDA is more strict in VS2010 but I can't seem to figure out what the actual problem is.
[Code]...
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Oct 31, 2011
The format I use in the file I am reading is this: [property name]=[property value],[property name]=[property value],[property name]=[property value], [etc...]
I coded the following, but I pinpointed an error on the very last line of code shown here.[code]...
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Jul 21, 2011
For example, I have string variable (MyString) as below.MyString = "First word || second order || third example || fourth item || fifth stuff"
There are separator "||" at MyString variable. I want MyString variable is spited based on separator "||"and stored it into new array variable.
Could you advise me the most efficient code to do this job in VB?
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Nov 22, 2011
provide a simple example code for displaying a string array of (9x13) values in a datagridview control. I am lost in the complexity of data binding and datagridview controls. I am an experienced VB6 programmer and cannot seem to grasp the transition from flexgrid control to datagridview control.
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Mar 2, 2011
So strings are reference types right? My understanding is a reference to the string in the heap is passed even when you pass the string ByVal to a method.
String myTestValue = "NotModified";
TestMethod(myTestValue);
System.Diagnostics.Debug.Write(myTestValue); /* myTestValue = "NotModified" WTF? *[code].....
And what is going on under the hood? I would have bet my life that the value would have changed....
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Feb 3, 2012
I am trying to use string.format on a url to pass several values into the string. It's probably a simple error but I cannot get the following code to work. It doesn't even build the string.
Public Sub getStockData()
Dim client As New WebClient()
Dim url As String
[code]....
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Mar 6, 2010
Does the following work in VB 2008 for passing an array to a function:
Public Function functionname(ByVal array1() As Short, ByVal array2() as Short) As Short
Also, can ByRef be used in place of ByVal?
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Feb 4, 2011
I have 2 arrays X(n) and Y(n) where n can vary programmatically, no set value. I want to pass these two arrays between two subroutines.
Sub sub1()
...
call sub2(X,Y,n)
end sub
sub sub2(x,y,n)
...
end sub
I want to know how to prepare the arrays for the "call sub2" and how to extract the arrays in "sub2".
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Jan 13, 2011
i have collection of data in an array. i need to pass it to web service as an array. how can i do that?
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Jun 22, 2010
I have a VC++ DLL, which returns the sum of two long double values, passed as one dimensional array?l the right syntax to pass array to this dll from vb.net
currently, my code snippet is as follows: DllClass.vb
Imports System
Imports System.Collections.Generic
[code].....
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Nov 20, 2009
I want to pass the entire array to the next function[code]...
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Nov 23, 2009
i got the output of my project and it is displayed in the RT BOX and saved locally.. the values are stored as arrays.. the RT Box will display three values time, conc and preconc.the time, conc and preconc values are stored as arrays. my problem is, i should pass this values to the next form FORM2.VB.. and display the values in a graphical format.how to pass these arrays from one form to other??
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Nov 4, 2009
how can u pass your array to another form
like example
FORM2
public test(2) as string
test(0) = "test1"
[Code]....
how can i get the value from the array test(0) in form 2 to in my textbox in form 1?
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Jun 12, 2009
i need to pass array value to a function , here are the details
function MyTest(byval a as integer, byval b() as string)
if b is nothing
msgbox("no array")
[Code]......
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