Import And Call Unmanaged C Dll With Ansi String "char *" Pointer String From .net?
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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Oct 28, 2009
I'm making a "wrapper" for an unmanaged DLL (written, I'm fairly certain in C). I have a c++ "wrapper" that I'm trying to convert to VB.net. I've got most of the program working, but I've hit a brick wall.
I'm trying to convert the following two structures from their c++ versions to their vb.net versions. I cannot be sure which is the problem because both must be passed at the same time. The error I am getting is thrown by the object and indicates "Invalid structure size specified". I can cause this error on other objects when I either don't set the dwSize variable, leave off a parameter or change the parameter type incorrectly. Note that the dwSize parameter is supposed to contain the size of each structure. I'm successfully calculating that for my other structures and I'm using the same method on these and the results appear correct, so I do not believe the problem is found there. The object uses a lot of structures and the rest of them are working. These two are the only ones with a) an unsigned character pointer b) an unsigned long array and c) doubles.
C++ versions:
CODE:
I don't think I'm missing any parameters - the help file seems to agree with me on this, but it's theoretically possible that there is something missing (though I don't think so for other reasons as well). My suspicion is that it's dwPalette, pImageData or pMaskData with (in my uninformed opinion) more suspicion on the pImageData and pMaskData.
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Jul 13, 2010
I am trying to the copy the value from string to char array using String.CopyTo() method.
Here's my code
Dim strString As String = "Hello World!"
Dim strCopy(12) As Char
strString.CopyTo(0, strCopy, 0, 12)
[code]....
Edit : I get the this error at runtime.ArgumentOutOfRangeException Index and count must refer to a location within the string. Parameter name: sourceIndex
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Dec 16, 2008
i want to read a character 1 by 1 from a string and a .txt, i know all about stream reader so for the .txt would it be somthing like:textbox1.text = tr.readCharacter.i would prefer to be able to read from a textbox or String array though.
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Mar 30, 2012
I need validation for string to comply with next: no space char starts with one delimiter char ends with one delimiter char has no other char as delimiter char. Updated sorry missed that should only be one delimiter char at start and at the end
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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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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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Aug 28, 2010
I'm calling an API that returns a string pointer but I can't find anyway to return the string it points to.
Is it possible in VB.Net, I see VB6 had a STRPTR function but I can see a .net alternative.
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Feb 3, 2009
I have just started to try to duplicate what I have done in Autohotkeys language.
What I need to do is point to a string variable - I will explain.
I'm reading from my own asci font files that contain big letters made up of characters, used for chat forums: EG.
[a_ch]
___oo___
__o__o__
_oooooo_
[Code]....
What I then want to say is a_ch=letter. But it is in a loop, so I can't do it directly. I want to point to lettername which contains the string of the variable name.
How can I point to the address of lettername?
In autohotkey language, it would be easy:
%lettername%:=letter
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Jul 14, 2011
I have a DLL that I am importing:Declare Function QueryInfo Lib "mydllname" (ByVal DevName As String, ByVal pcQueryParam As String, ByVal Result As String, ByVal Length As Int32) As Int32
[Code]...
Anyone have an idea what the issue could be? If I run similar code in VB6 (only diff is mtStatus = String(mtValueSize, Chr$(0)) ) it returns what I expect.
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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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Jun 27, 2012
I have built a DataTable from my database. Then I am looping through the rows and trying to access a string, however the value is being returned as each character in the string.
For Each theseRows In DisplayForm.MainTab.Rows
If theseRows.Item("Last_Name") = userLast And theseRows.Item("First_Name") = userFirst Then
[Code]....
The Trap_Code values are two or three letter strings, the returned value is each letter once at a time. The loop seems to cycle through the individual characters of the string as an array rather than display the entire value, which is what I was hoping for.
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Aug 24, 2009
The following code:
If checkboxList.Items(i).Selected Then
.Fields("DESC1").Value += checkboxList.Items(i).Text + ", "
End If
should produce output such as "A, B, C,(space)", which will then be bound to a dynamically created GridView. I would like to remove the last two-char string, that is ",(space)". How can I do this?
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Jun 5, 2011
I am writing a database and need to post a value in a lable to a sql field.the sql datatype is set to money.when posting i have
CMD.Parameters.addwithValue("@Claim", LBCLAIM.text)
when posting i gett an error
cannot convert a char vaule to money. the char vaule has incorrect syntax.
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Apr 29, 2009
how can I cut the 1st 3 char in a string in vb 2008?
For example:
Dim i As String = "ABCDEF";
I want to only cut the 1st 3 char and the system will only display "ABC" after the 'cut' action done.
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May 27, 2012
I want to convert say Input: textbox1.text=blabla Output: blabla becomes into: textbox2.text=(char45 & char34 char45 & char34 char45 & char64 )
[code]...
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Apr 28, 2011
Im wanting to create a function that receives a string and moves the first letter to the end and returns it.
Public Function moveLetters(ByRef word As String) As String
Dim length As Integer = word.Length
Dim chars(length) As Char
[code]....
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Oct 29, 2008
what is the best way to remove FileFinder1 from this string:
"C:Program FilesFileFinder1"
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Apr 18, 2010
Basically the first letter of a string must be a certain letter. At the moment the only way I know how to do it is as follows:
If sConsignmentNo(0) = "J" Or sConsignmentNo(0) = "C" Or sConsignmentNo(0) = "U" Or sConsignmentNo(0) = "N" Or sConsignmentNo(0) = "H" Or sConsignmentNo(0) = "S" Or sConsignmentNo(0) = "V" Then
Basically listening the same thing out over and over. Is there a way I can say, If sConsignmentNo(0) = ListOfValidEntries i.e J,C,U,N etc?
Using Visual Basic 2008 and cant use regex!
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Mar 23, 2012
I have a string like this.
Dim str As String = "code"
I need to break this string down to an array of characters like this,
{"c", "o", "d", "e"}
How can I do this?
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Aug 20, 2011
I have a string that goes like "abcdefg..."
I would like to find the index where the letter d is at, so I can get the number 3.
I managed to do it by looping through each letter in the string, but that doesn't sound very convenient.
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Jan 15, 2012
Function to test first char of string
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Nov 10, 2008
my question is how can i check a string for a specific char (for example, in the string:"242.421" theres the char "." how can i make a rule so that char can only be typed once... (in a textbox) so when a user click the "." button on their keyboard it won't allow it again (more than once)
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Apr 29, 2011
Hello all, im now trying to create a way to replace the last char of a string with "4"[code]....
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Dec 1, 2009
I want to replace a char at a specified index of a string.
Short of using the .Remove and .Insert methods I was wondering if there is an easier way.[code]...
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Jun 14, 2011
I want to split a string with this array of char
Dim sepa As String = " '"",.;:(){}[]·#|-_<>+¿?=/&%$‚¬@!¡"
The question is how do I include in this string vbcrlf? So I can do the fallowing:
dim palabras as String() = RichTextBox1.Text.ToString().Split(sepa)
I tried:
Dim sepa As String = " '"",.;:(){}[]·#|-_<>+¿?=/&%$‚¬@!¡\r\n"
But it does not work.
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Feb 6, 2012
I am developping an app which talks across a network and will eventually be used to read in a text file (on the client) and transfer it to the server. Currently, the server and client succesfully connect to each other using the Tcplistener/Tcpclient classes. I am now trying to send some data across the network using the networkstream class, which I have implemented.Currently for testing purposes i am sending a char array which contains the characters "hello" which succesfully sends and outputs to console on the server. Although, "hello" is followed by a long list of whitespaces. I have tried converting this to a string array on the server and/or client and using the string.Trim() function (amongst trying many other things over the past couple of hours) although the output remains the same.
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Feb 17, 2011
Why when I wrote in a xml the char "&" it appears & ??
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Feb 24, 2011
I have string that is equal to 112233. I need to insert "-" after every second char in string so i wrote the
Dim str1 As String = "112233"
Dim str2 As String = ""
Dim i As Integer
[code].....
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