Importing Class From C++ Dll?
Dec 11, 2011
Ok, I've been fighting this for days and so far haven't found very much helpful information on the web. Apparently this isn't a very popular thing to do since there isn't much out there. I'm hoping someone here can help me out. I don't know very much about dll's or implementing classes in vb, so please correct me if my thinking is wrong.If it's relavent I'm using Visual Studio 2010.I'm working on a much larger project, so I've created a greatly simplified version to test and and ask questions about.Here's the situation:I've created a class in c++ that I now need to create an interface for in vb. As I said before I've created a much simpler class and compiled it as a dll. There are two functions in the dll:
[code]...
The setTestVar function simply sets the value of a member variable, and getTestVar returns the value of that variable. I load the setTestVar function from the dll like this:
[code]...
Then when I click a button, I call:setTestVar(9) This results in an "AccessViolationException was unhandled" error. "Attempted to read or write protected memory...."After thinking about it, I guess this would make sense if the constructor in the dll was never called (and thus the variable into which I'm trying to store data doesn't exist).So the question becomes, how do I call the constructor in the dll from vb such that I have some sort of handle or reference to that object when the call returns from the dll? Without a handle, I won't be able to access any of the member variables. Is this thinking close to being correct? Or is the problem something entirely different?So again, how do I call the constructor in the dll (from vb) and somehow have access (from vb) to the object that it creates?
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Mar 24, 2010
I am working on a Java project and I am having some difficulties with importing a .class file. Unfortunately I do not have access to the source code of the file?
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Jul 4, 2011
the problem i met is that i have iis 7 running on my pc.in the root file, wwwroot, i have a website folder, namely [apex] which is a virtual directory. in the folder is a bin folder containing a compiled class with namespace.then in an aspx file, i tried to import the namespace and use the class inside the namespace.
[code]...
the namespace and classname has been checked well, no mistake. but at compiling stage, i got "type is not defined " message. ok,then, in iis 7 control panel, i convert the whole website folder from "virtual directory" to "application" type. the problem goes away!
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Jul 16, 2010
When I import a class to a form and use it I get this error:
An error occurred creating the form. Additional information is found in Exception.InnerException. Error: The document refers to itself of the default instance created during the formation of infinite recursion. Set a reference to the form constructor using the form attribute of Me.
The code is...
Imports TCP.SystemBuild
Public Class MainForm
Dim SystemBuild As New SystemBuild
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Oct 27, 2011
We have a typelib where we define some constants. One of our sets of constants is created using the module keyword:
module MyConstants
{
const int Const1 = 1;
};
I use tlbimp.exe in a bat file to generate a primary interop assembly for internal use.If I create a VB .net project and add a reference and browse to the .tlb file and import it, the result I see in the browser window is a class named MyConstants. If I click the class, the right hand pane is empty - the class contains absolutely nothing.
If I add a reference to the primary interop assembly, I also see the class MyConstants int he browser window. When I click the class, the constants show up.This is in Visual Studio 2010 (RTM). Why does VB .NET add reference via brwose to the .tlb file differ in this case? Is this a bug in VB .NET or the tlbimp.exe tool?
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Nov 16, 2011
Here is what I have in my file
Option Strict On
Imports MyNameSpace.MyEnum
Public Class AwesomeClass
[Code].....
But since MyEnum isn't defined in the subclass it won't work. I am not very familiar with what these types of things are called, but I think that I am import a type definition of sorts. Since I am Importing, and not defining, it is only available in the first file. Basically, I want to include MyEnum as part of the class but I don't how to do it. I don't want to copy/paste it over, and I don't really want to write Imports ... at the top of all of my subclasses.
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Dec 16, 2009
If Class X is within the scope of Class Y, is X a subclass of Y?If Class A is a sub Class of B, then is Class B considered a super class of A?if Class C inherits Class D is Class D a superclass or parent of Class C?if Class E extends Class F then we can consider Class E a child of F?if Class G inherits Class H and is within the scope of Class I then who is the parent of Class G? Classes that inherits Class J and classes that are within Class J are all sub classes of Class J?
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Apr 15, 2010
I have put this code in the global form Inherits System.Windows.Forms.Form. And then in the form that will inherit this from the global Inherits MenuStrip. "MenuStrip" is what the global form is called. But keep getting this error: Error1Base class 'MenuStrip' specified for class 'Lesson2' cannot be different from the base class 'System.Windows.Forms.Form' of one of its other partial types.
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Jul 22, 2011
I have a class (see below)
Imports Microsoft.VisualBasic
Imports System.Data.SqlClient
Public Class ClientProfile
#Region "Variables"
[CODE]...
It is in the file ClientProfile I have placed in both App_Code and also App_Code/Models
In my code behind I have the following
[CODE]...
The last word, "ClientProfile" has the scary squiggly red line below it. It is not recognizing my class.Even the Intellisense is not picking up te class. Do I have to register the class file in any way?
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Apr 11, 2011
for example i have a.exe and b.exe ( the a.exe is an vbApp, and b.exe is an executable file ), now.. it is possible to include the b.exe into a.exe and then running it from a.exe, for example importing the b.exe into vbProject and then running it without extracting it.
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Apr 9, 2010
I have a form that allows a user to import a spreadsheet. This spreadsheet is generally static when it comes to column headers, but now the users want to be able to include an optional column (called Notes). My code crashes when I try to read the column from the spreadsheet if it doesn't exist.
Dim objCommand As New OleDbCommand()
objCommand = ExcelConnection() 'function that opens spreadsheet and returns objCommand
Dim reader As OleDbDataReader
[code].....
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May 1, 2009
I have created a web service in a virtual directory using VS 2008. I have tested the service by going to the .asmx page and everything is working fine. So I selected the "Add web reference" option under the solution and typed in the .asmx URL. It found the web service successfully and added the reference to the project. However, when I try to import the service namespace using the same name as the directory under the "App_WebReferences" folder, it doesn't recognize the name and gives me an error if I try to import it. Have I missed any steps in the process?
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Jul 4, 2011
I am trying to write my first DLL and am struggling to get it working correctly and am receiving a variety of errors. For my Hello World DLL I was trying to follow this page [URL].. but as it was very old and referring to VB 6 I am now trying to use the instructions on this page: Essentially, what I have done is to follow all of the instructions on the second link, but then instead of calling it from C++ I call it fro my VB application (I have successfully managed to call DLLs from VB in the past). When I try to call the Add function (or any others) I get a BadImageFormatException error thrown saying "An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)" but I don't know what I am doing wrong. I have tried calling an alternative C++ function that is declared as a void and takes no arguements in order to completely avoid the problem of matching the data types but I get exactly the same error.
I gather that this is sometimes to do with target architectures, and have tried setting the C++ compiler to build it as both a Win32 DLL and as an x64 DLL, and each time changed the VB settings to match the outut type of the other but this doesn't seem to make any difference, and for some permutations even makes it worse with it saying that it can't find the entry point in the DLL that I'm calling.
I am completely new to this and am now at a loss for what to try and what could be going wrong,. The VB import is as follows:Private Declare Function Add Lib "DLL_Test.dll" (ByVal a As Double, ByVal b As Double) As Double Private Declare Sub HelloWorld Lib "DLL_Test.dll" ()
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Jul 10, 2009
I inherited a DLL project developed in VB6; this project has to be integrated to a VB.NET GUI. At the moment, the project is integrated succesfully except for one detail that it is taking a lot of my time.
Every time that has to load a form from the COM DLL, the execution of the program loops and gives an OutofMemoryError -- I imagine the error is because the executing is looping by trying to load and reload the Form1 from the DLL. So, is it possible to import graphical controls and components along the DLL, such as Form1? or, do I need to separate them in order to import the DLL succesfully?
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Sep 14, 2010
i am importing a csv file into my app. this is to let the users pull in info they have in excel.somehow, they have slanted apostrophes, and not tick marks. so when i open the file stream and do the import, it pulls in those characters as blank boxes (unknown char).
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Nov 27, 2009
I am importing a csv to my datagridview (all works well)
CODE:
I now want to save the imported data to my bound dataset:-
Am I trying:
CODE:
But it wont save the data.
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Sep 1, 2008
Is this possible? I upgraded to VB Express 8 and have several programs that I would like to import into VB Express 8 from VBE 5. But everything I have tried so far has not worked.....This is the first time I have imported files from one computer to another. I have tried to save the file as a zip file and unzipping it in VB 8, but that didn't seem to work.
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Apr 9, 2010
I am trying to import a CSV file to SQL Server 2005. The CSV file has several fields, but I am not sure of the best way to import them. This is what I have so far.
[Code]...
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Mar 18, 2011
I'm trying to import the WinLicense SDK, but When I try and add it as a reference, it doesn't seem to work. It says it's not a valid COM reference. I was just wondering if any of you guys protect your programs with WinLicense, and how to protect my applications with it... I'm trying to use the APIs so I can use the HWID Protection.
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Jan 10, 2010
I have some form/vb in another project that I want to import to a new one. There are three files with these extensions - .vb, resx, and designer.vb. Which do I copy and how exactly?
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Sep 16, 2011
In VB, when we adding a new references - in my case web references -, it simply type namespace followed by the class name to make a new object.For example:
Dim obj As NamespaceName.ClassName = New NamespaceName.ClassName
Then I apply this concept in C#. So my code will be:
NamespaceName.ClassName obj = new NamespaceName.ClassName
...and it doesn't work.Actually, is there any difference about Importing Namespace between those two?And also can you give me a little explanation about Project-Wide Default Namespace Imports in VB?
UPDATE:My point is why "In C#, When I've typed NamespaceName, the ClassName was not listed in the Intellisense?".However, it did well in VB, do I have to import something?Maybe, there is something to do with the term "Project-Wide Default Namespace Imports". (CMIIW)
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Nov 5, 2010
I am having trouble importing mySQL to my project. When I use the syntax Imports MySql.Data.MySqlClient a warning shows up saying that "namespace or type specified in the (code) doesn' contain any public member or cannot be found"
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Aug 6, 2010
I have a VB file that imports System.IO, but only uses it is a couple of places.My co-workers and I were wondering if there is a small performance boost if we just use System.IO explicitly were we need it (IE., System.IO.MemoryStream) instead of importing it.
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Apr 7, 2010
I have a datagridview on my form with 7 columns and a variable number of rows. It's used to track stats on games (kills, deaths, assists, etc.) The way I ended up saving it was in a .xls file for the simplicity of being able to edit it in excel as well as my program. how to import the file back into the DataGridView though.
Here's the code I'm using the save the file:
VB.NET
Private Sub exportExcel(ByVal grdView As DataGridView, ByVal fileName As String, _
ByVal fileExtension As String, ByVal filePath As String)
' Choose the path, name, and extension for the Excel file
[Code]....
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Feb 10, 2010
I'm trying to write a small application that imports data in a column from a csv file into a table in access. I'm very new to programming, but this is what i've come up with so far. It runs, but it's not actually bringing the data over to my database.
Here is the code:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim dbPath As String
dbPath = "f:db1.mdb"
[code].....
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May 4, 2011
I'm importing a CSV without headers into a DataGridView using:
If ofd.ShowDialog(Me) = DialogResult.OK Then
Dim fi As New FileInfo(ofd.FileName)
Dim strDirectory As String = fi.Directory.FullName
[Code]....
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Jan 27, 2009
I want to create a button that will open up a form that will be used to browse a filesystem and select an excel sheet to import into access. I'm a noob at .Net and I needsome help on how to do this.
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Apr 22, 2010
I have 2 projects. The first project has a form called Form1 in it and I want to import this form into Project 2 and have it fully working without any problems.
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Mar 17, 2012
I am using VB 2008 for this little first game I am trying to make. Currently a grid of rectangles is being generated when a button is pressed and when you click on the grid I am attempting to import the relevant image into the selected rectangle. Looking through the available options I can't find anything relevant to import the image onto that selected rectangle. Is there another method of importing onto a code generated grid? my current relevant code is: brackets, its my first time here.)
If Form1.MousePosition.X < rect.Location.X + rect.Width And Form1.MousePosition.X > rect.Location.X And Form1.MousePosition.Y < rect.Location.Y + rect.Height And Form1.MousePosition.Y > rect.Location.Y Then
[code].....
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Sep 5, 2007
This is in vb 2005, and I would like to be able to click a button (i.e. export to excel, import from excel) and do this.If you need any more information then just let me know.
1)How do you export the data that is displayed in a datagrid to Excel.
2)How do you import data from an excel file, and fill the datagrid with that information.
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