C++ - Unhandled AccessViolationException Error Calling A DLL?
Oct 6, 2011
I'm trying to call a C++-compiled DLL from VB.net and I'm running into some problems. Seems like there's an obvious solution, but I can't figure it out.Here is the function declaration in C++:
MyFunction(int trailingaveragesize, double sigmasize, int myflag, int sizeSeries, double *Xdata, double *Ydata, int sizeinputparameter, int *averagePairs, double *PositionsSize, double *PnLSize)
I have a subroutine that was written in fortran that I need to call from VB.NET where all of my other functions are written. I did not write the fortran, and hardly know fortran. I am getting the below exception on my dll function call and don't know how to fix it. I wonder if it is due to incongruent variable lengths? I have the source for my fortran and compiled it using the g95 compiler. I have tried compiling it with a flag on which is supposed to force all of the reals to 32 bits (-r4). It weirds me out that you don't seem to be required to initialize variables before use in fortran. I thought it was supposed to be a ridged language.
I always get this error during the Paint event: System.AccessViolationException was unhandled. The weird thing is that it doesn't happen the first time it goes through.
Here's the code.
Friend CustomFont As Font = GetCustomFont()
Private Function GetCustomFont() As Drawing.Font Try Dim PFC As Drawing.Text.PrivateFontCollection
[CODE]...
Symbols is just a 2 dimensional array of characters.
I have problem in calling DLL file in VB.Net that I had Created it in C++... it give me this error message: "An unhandled exception of type 'System.EntryPointNotFoundException' occurred in test_dll_1.exe. Additional information: Unable to find an entry point named 'add_1' in DLL 't1.dll'."
This is my code in C++ (header file)
[CODE]............
The one in the main
#include "header_1.h"
double add_1(double a, double b){ return (a+b);
[CODE].....................
This code only for creating dll and I did created it correctly and i had tested it in c++ and it did works.... but in the Vb.net I had no luck with it...This is the code that I wrote it in the VB.net
Imports System.Runtime.InteropServices
Public Class Form1
<DllImport("t1.dll")> Public Shared Function add_1(ByVal a1 As Double, ByVal a2 As Double) As Double
End Function
[CODE].....................
And, I did put the .dll file in the bin folder, but also with no luck...
I am trying to find the time-outs the user has set for the PC similar in function to the command line:
powercfg /q SCHEME_CURRENT SUB_SLEEP but I want to do something a bit more elegant than firing off a command and parsing the values out of the captured output. I've managed to source a number of element examples from the net and cobble parts together into a program.
I've got a fair way but am now stuck on the call to powrprof.dll - PowerEnumerate function. I've checked it on Microsoft's site and my call seems to be okay yet it still fails with 'System.AccessViolationException was unhandled'
The error message that I've been getting for the past few months when trying to access functions of a specific third-party .dll using vb.net is this: "An unhandled exception of type 'System.AccessViolationException' occurred in test.exe Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
I've been researching this error message, and I have come to know that it is likely due to either attempting to access memory that isn't available or due to "enhanced" security features.I am trying to access a third party .dll. The functions in that .dll all deal in one way or another with Handle types (either returning them or accepting them as parameters). I understand that handle's can be essentially pointers to pointers (pointing to an entry in a memory table, which is itself a pointer), and I also understand that handle's don't, strictly speaking, exist in the .NET framework, but I do understand that through some combination of IntPtr's and possibly the Marshal class, they can be dealt with.
I don't believe vb.net's lack of a Handle type is the problem, because the dll function that I am calling, which on success returns a handle, returns a number <= 0 if the ip address it is searching for is not found, and the ip I specified doesn't exist. Also, the error really only occurs when executing the code from within the the Visual Studio environment. I compiled the executable and ran it 77 times(literally), and I only got the error on the 77th try.
I'm trying to find out all I can about this error. I would like to completely eliminate it. Could the error come as a result of something happening within the dll itself? The function asks for an ip address, and the ip address I have specified doesn't currently exist on the network, but as far as I know, the function handles that by returning a number less than or equal to zero. I am very confused as to what the problem could be. I have successfully interfaced with .dll's before. I've read about the hotfix for .NET 2.0 regarding this error message,but I'm a little skeptical. I've tried everything else I can think of, though, so I may give that a shot.I'm 100% certain that:
-I am calling the correct function within the .dll
-I am using a signature that matches the signature of the function
-The error has nothing to do with User Account Control.
The code is very simple to try to isolate the issue:
Imports System.Runtime.InteropServices Module test <DllImport("3rdparty.dll", EntryPoint:="#12")>[code]......
ok so i viewed some other question that are ruffly the same and i am still confused, here is the stacktrace
at Game3.My.MyProject.MyForms.Create__Instance__[T](T Instance) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 190 at Game3.My.MyProject.MyForms.get_Character_Creator() at Game3.My.MyApplication.OnCreateMainForm() in C:UsersMasonDocumentsVisual Studio 2010ProjectsGame3Game3My ProjectApplication.Designer.vb:line 35
[Code]...
also, where is game3.my.myproject, obviously its a line of code but what is it in.
i am in project of medical billing.i am on LogIn form in vb.but i have Erro - "InvalidOperationException was unhandle " and while i was run program it didn't say which line i had error.
here is my code.
Imports System.Data.OleDb Public Class login Inherits System.Windows.Forms.Form
I have made a tic tac toe board and when i go to debug the application i get a "NullReferenceException was unhandled". this happens diring this part of the code:
Dim conn As New OleDb.OleDbConnection Dim ds As New DataSet Dim da As OleDb.OleDbDataAdapter Dim sql As String
[code]....
The above code stops running at the point of the da.fill line with the error that the specified table does not exist.In my limited knowledge so far to me it looks like the operators table exists as it showing in the Solution Explorer.
Public CHandles() As Long Public SHandles() As Long Public rerrors() As Long
[code]....
Generates a SafeArrayTypeMismatchException was unhandled. Specified Array was not of the expected type error.I assume it means the SHandles, rerrors, and CHandles arrays but not sure.
I'm getting a "TypeLoadException was unhandled" error. The description says Could not load type 'dnUtilities.OtherFunctions' from assembly 'dnUtilities, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.
So i've got a class library project. I've built that into a dll and am referencing it in a project in another solution. The name is "dnUtilities" and i've stored a lot of subs and functions inside it. I just got this error when i added a new module and tried calling a sub from it. I've got no idea why this error is happening since all the other functions from the other modules work. Besides modules i've also got a usercontrol in the dll. The framework of the dll and my calling project are both 3.5.
I was testing out an application that I created which then I recieved an error as said in this topic title. The application that I am making is one where it requires 2 form GUIs, my main one is called frmConferenceRegistrationSystem (the first picture) and my secondary one is called frmConferenceOptions (The second picture) and what they are supposed to do overall is total up the cost of registering for a conference that is selected in frmConferenceOptions and the error that I am recieving is within the ElseIf statements in the frmConferenceOptions form (third picture and first section of code) And also here is the rest of my code for both of my form GUIs at the bottom of this topic
If ltbList.SelectedItem(IntrotoECommerce) And ckbConferenceRegistration896.CheckState = CheckState.Checked Then My frmConferenceRegistrationSystem Code: Public Class frmConferenceRegistrationSystem
I am making a simple calculator and it's saying InvalidCastException was unhandled when I try to debug it, here's the code, please tell me whats wrong with it: (and yes I have renamed the textboxes to addequals etc...
Public Class Form1 Private Sub WebBrowser1_DocumentCompleted(ByVal sender As System.Object, ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs) End Sub
i have a probleam with my coding.The error which i got is olehDBexeception was unhandled.In my coding here i am developing function use to subtract number in database based on user input.I dont how to solve this error? I also highlight the line cause an error and also i attach picture of the probleam.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 'open db connection'
[code] I'm basically trying to see if a record already exists. My problem is when I run this I get a "ArgumentNullException was unhandled" error It occurs on the line "dbAdapter.Fill(output)" in the sub.
I have some trouble in SMS gateway project using VB.Net (VS 2010)while programme was running, I found error "InvalidCastException was Unhandled", then my programme cannot continue. below I copy the code of the programme :
---------------------------------------------------------------------------------------------------------------------- Option Explicit On Public Class MessageReceiver Private TPMessageTime As String
When editing my DGV (SSN number 123-12-0000 to 123-12-1000), I am getting an error.
Unable to cast object of type 'System.Windows.Forms.DataGridViewTextBoxCell' to type 'System.Windows.Forms.DataGridViewCheckBoxCell'.
in the following code
Private Sub dgvResults_CellValueChanged(ByVal sender As Object, ByVal e As DataGridViewCellEventArgs) If (Not IsHeaderCheckBoxClicked) Then RowCheckBoxClick(DirectCast(dgvResults(e.ColumnIndex, e.RowIndex), DataGridViewCheckBoxCell)) End If End Sub
It happens after I press enter or move focus to another column. Any idea why this is happening?
Here iam trying to insert some values to SQLServer 2005 Database.The following error displaying.I changed the corresponding column size,still the error persists.how can i sove this error-:
'String or binary data would be truncated. The statement has been terminated'
iam trying to insert some values to SQLServer 2005 Database.The following error displaying.I changed the corresponding column size,still the error persists.how can i sove this error-:
nullrefererence exception was unhandled. I'm getting this error. could someone pls help
here is my code
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click WebBrowser1.Document.GetElementById("Email").SetAt tribute("value", TextBox1.Text) WebBrowser1.Document.GetElementById("Password").Se tAttribute("value", TextBox1.Text) WebBrowser1.Document.GetElementById("Signin").Invo keMember("Click") End Sub
I have some code that uses the Windows Media Player Library capabilities to get around using ID3 tags. I keep getting this error however, whenever I add 1000+ songs to the datagridview:
For Each File_FullPath As String In My.Computer.FileSystem.GetFiles(My.Settings.Path, FileIO.SearchOption.SearchAllSubDirectories, "*.mp3", "*.m4a") Dim WMP As New WindowsMediaPlayer WMP.URL = File_FullPath
[code]....
Here is the code I'm using that gets the error:The problem is I need a way to clear the WMP.mediaCollection, but I don't know how.
I have created a vb.net console application when i am running the source code it will work fine.But when i am running the Executable file it is throwing an exeption like "System.TypeInitializationException was unhandled".In my application i have used MCL PrinterMonitorComponent
I am working on an application with a friend and I am getting an error.The error says:
System.InvalidOperationException was unhandled Message=An error occurred creating the form. See Exception.InnerException for details. The error is: The process cannot access the file 'C:UsersAdministratorNotesWebSiteNotes.txt' because it is being used by another process. Source=Website Notes
[code]....
Now I know why it is throwing this error but nothing I do will stop it from showing up.At the top of our form we have a module that we use to check if a file exists on the computer and if it doesn't then it will create the file.I have tried accessing that module from the form load event but with no luck as it still throws the error.
