Allow More Than One Instance Of VB App To Access Data Files?
Jan 1, 2012
I have just completed an upgrade of a VB6 app to VB.net (2008). Everything works as it should except for one (essential) part. I cannot open more than one instance of the built app without getting a file access error. Now don't laugh but my program uses Random Access files to store the data (i know, i know the 1990's called and they want their programmer back). Anyway I've been using this method since the early 90's and it's never let me down. Until now that is. VB6 allowed any number of users to access the files but for some reason VB.net gives the following error: The process cannot access the file "C:lah blah" because it is being used by another process.
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May 3, 2011
I was create Access database with Access 2003. I create VB project with Visual Studio 2005 Standard With connection wizzard I create coonect with this Access database, select all tablesI see this database inside Data sources and inside Server explorer Test connection is OK When I drag and drop table from Data sources, Wizzard don't create DataGridView, DataSourceBinding etc .. and I see popup window with mesage: Object reference not set to an instance of an object and then "game over"
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Sep 6, 2010
how do you save data stored in an array of records (structure) to a text file using StreamWriter? I currently have
Private Sub btnSaveToFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveToFile.Click
Dim sw As New StreamWriter(New FileStream("EmployeeDetails.txt", FileMode.Create, FileAccess.Write))
For Each record As EmployeeType In employees
[code]....
but it doesn't work. My array is fixed and currently has 3 elements (for testing purposes). If I enter two records and add these to the structure I get the following data saved to the text file:
123,helen,66000
879,john,89975
0,,0
How do I stop unused elements of the array being included when writing to file? Should I use a dynamic array instead and if yes, how do you use dynamic arrays with structures?
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Sep 1, 2011
I have no problem doing a select statement from a database and displaying it.An I have no problem inserting data into a sql database table. However with this issue I have to grab the data an insert it into a totally different SQL 2005 instance.
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Apr 8, 2011
I have added some files that I need to be downloaded to the Application start up path. So I set Build Action as content now the files have been copied some where [code]...
How can access file from the application.
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Apr 8, 2011
I have added some files that I need to be downloaded to the Application start up path. So I set Build Action as content now the files have been copied some where
C:Documents and SettingsTestUser.ANNAMLocal SettingsApps2.0DataHVDRBMY5.8AA858AT9VM.TNP est..tion_2d7cfc137d9c2c74_0001.0013_432bd4561850d290Data
How can access file from the application. My problem since it is a dynamic path will it be same folder count so that we can use like ....Data Some think like this
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Oct 1, 2009
New to VB... I am trying to access .SYS (system files) located in the following folder path (example) My Database NameVIEWSSYSTEM VIEWS in the Object Explorer of my SQL Database. In walking through the Data Source Configuration Wizard for data connectivity I select DATABASEVIEWS and the SYSTEM VIEWS sub-folder is not available for selection. In general: What is the best method to access System Files using VB Data Source?
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Sep 15, 2011
How to connect vb .net data grid view to a ms access database files
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Mar 3, 2012
I'm just getting started with Visual Studio (2005), and my aim is to write a fairly simple application in Visual Basic that will need to store some data to disk.What I really want is to be able to send the application to the end users (xp, vista, win7) and have them just be able to use it without having down download all kinds of extras. For example I'm guessing that if I use an SQL database in my application they will need to download SQl server express or some other sql downloadable?
If so is there a similar downloadable for MS Access?I'm just in the 'seeing how things work' stage at the moment and I don't want to waste time going down the SQL track just to find it won't actually work unless my users all download SQL to their machines (which they won't want to do).
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Jul 24, 2010
I have an application that has a tabcontrol to handle multiple documents, just like Notepad++. And I also have file association working correctly with it.All I want to do is to make it open the double-clicked file onto a new "codetab" instead of creating a new instance of the program just to open a file.
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Mar 31, 2010
I create an Instance of Access to view a report through my app.I would like to check if an Instance of Access has either already been opened by the user, or by the app. If so, use that instance.
Dim oAccess As Access.Application
Public Sub CreateAccessInstance()
Try[code]...
As it stands now, It creates multple MSACCESS.EXE processes which are running until I exit the app.
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May 15, 2012
In Windows Forms (Vb.net) how can I access the properties without instance (new) ?Form1.Property = "" ? the property deceleration is not static? what is called this way of deceleration?While you can't access Class1.Property!
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Nov 6, 2009
After I formatted my laptop and reinstalled Visual Studio 2005, I receive a lot of same error as below message.
"Access of shared member through an instance; qualifying expression will not be evaluated"
If I click the error, it direct me to the line and all 102 error suggest me to add "Windows.Forms." before "DialogResult.OK". Should I add something on "Reference"?
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Aug 2, 2011
I have a question regarding namespace names and classes: If I have a class called cVeloConnect in namespace VeloConnect.
[Code]...
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Aug 23, 2011
I am trying to import a bunch of excel 2003 files all with A:H columns and they are under the same headings etc. into a table in access 2003 database. This is a module in access im making. Im using a file search to look for every file that begins with Format (which they all do ) to get at all the files in the folder path. is there a more efficient way to do this? somehow select all files in a folder? and import each to the same table in access? The DoCmd.TransferSpreadsheet seeems to take each file path individually so I'm not sure how to get each file name in the folder to import it.
I have this at the moment:
Sub Import()
Dim db As Database
Set db = CurrentDb
[Code].....
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May 22, 2012
Ok I know this question has been asked to death but I still have not seen a good answer. I have created an application in VS2010 using VB.NET. In my application I have an error log that is an XML file located in the Public gstLocalErrorLogLocation As String = Application.StartupPath & "ErrorLog"that gets written to in the event of an error so I can trouble shoot application easier. My application also downloads files from our FTP site and puts the files in Public gstLocalDownloadLocation As String = Application.StartupPath & "download"So I have files that get read and written to as well and created and deleted all in the Application.StartupPath which is either "c:Program Files(Application Directory)(Some Directory)(Some File)" or "c:Program Files (x86)(Application Directory)(Some Directory)(Some File)" depending on 32bit or 64bit Windows 7.
After creating the setup I install it on my test machine that have both Windows 7 32bit and 64bit.Everything in the application works great till I have to write to, delete or creat a file in those directories above. I know it is an access issue and the UAC. This will get installed on numerous systems so the options I have seen to change file or folder permission on the computers manually is not an option.What has to happen is after I install the application it just works like when you install it on XP. Some post have suggested that you us a user with administrator privilages or group which is all fine and dandy but the user I have used to test the application has all of that.
So what I am asking is how do you create an application with VS2010 in VB.NET that after creating a setup package and installing on Windows 7 will just work with out "Access to the path c:Program Files(Application Directory)(Some Directory)(Some File) is denied." If I have to install this on 100 Windows 7 computers it has to be a concreate no manually doing anything just install and work like when we installed on XP.
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May 24, 2010
Actually I want add some folders and files to MSI. Through custom action i want to copy that added folders and files to some destination/target folder.
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Mar 25, 2012
In visual foxpro i can access to the code of the events inside of a INSTANCE of a that is in a group box but this is not the case in vb.net how can i do it? Here the images in vfp and vb.net
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Mar 3, 2011
Here's an example of what I'm talking about...
Public Class Sample1
Public Shared Function MyValue() As Integer
Return 0
End Function
Public Sub Code()
[Code]...
Me.MyValue gives a warning in VB.NET and (the equivalent code gives) an error in C#. Is there a particular reason for this? I find it more intuitive/natural to access the shared function using 'Me.MyValue' - but I avoid it to keep my warnings at 0. Did someone else just decide 'Nah, it makes more sense to do it the other way' or is there some technical reason I don't understand?
EDIT: I was thinking of it wrong, more like a 'sub class' in OOP. Even if something is declared in the base class, you access it through the instance you have. But that relationship is not the same with shared or static.
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Dec 28, 2010
The context of this question is that I am trying to debug performance issues (apart from the obvious ones I already know about and can find).I inherited a code base (VB.NET) for an ASP.NET app. This is an app that was developed way back in .NET 1.1 days, and was the first .NET app for a lot of the developers who worked on it.
In this code base is a class called DatabaseUtility that contains several Shared Public methods as well as non-Shared Public Functions and Subs for CRUD operations to the database (SQL Server).
It is common in my "BL" that a method creates an instance of the DatabaseUtility which essentially figures out what the connection string should be and opens a connection, as well as giving the developer a handle to the other methods contained within it.Dim utility as New DatabaseUtility()
Once I have that, I start to create parameters that I am going to pass to one of the methods in DatabaseUtility (like GetDataSet). There is a Shared method in my DatabaseUtility called CreateParameter which does essentially that. It creates a SqlParameter object so I can add it to a Parameters collection.
Now, the code base is littered with a lot of this:
utility.CreateParameter(...)However, because CreateParameter is a Shared method, I am not sure what is going on behind the scenes. I know because it is a Shared member that an instance of the DatabaseUtility is not created when I call it like this:DatabaseUtility.CreateParameter(...)
However, because I am calling it from an instance (utility), does that change the behavior at all?
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Jul 16, 2009
I have been asked by a code snippet to add the instance of class that contains data i want to add to an XML file, the only trouble is i am not sure what an instance of class is. Is it something that looks like this: [Code]
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Mar 8, 2008
I am linking a report within asp reportviewer to a drop down list, but keep on getting an error 'A data source instance has not been supplied for the data source 'DataSet11_NewSelectCommand'. I cannot see anything wrong in the code though,
Imports System.IO
Imports System.Web
Imports System
[Code].....
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Jul 21, 2009
How can this statement give this error "Object reference not set to an instance" what is this means for0.?[code]...
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Feb 25, 2012
I have 5 websites running on same server and I have some sql tables that I access frequently. that was time consuming and by defining them shared I pumped them in memory. So my application is accessing those static data tables from memory quite efficiently.
But I realized I did a mistake and I occupied my memory unnecessarily while I keep same tables 5 times for each web application. Now I need to find the best way to share that table only 1 time. my options are;
1) using a local database - sql CE. my original sql database is on other server. so it makes the access slower but I can add a sql CE database(to be honest I never used it and dont know if it gives me anything) to access only these tables while they have static rows.
2) I read over forums that making a WCF using tcp binding. not sure if it will give me any advantage.
3) windows service: is it faster than wcf? programming is defiantly faster as i have experience with winservice but nor sure about performance.
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Nov 29, 2010
Okay so what I'm trying to do is get the filename from OpenFileDialog/SaveFileDialog, only without the full path, and dump said filename into a variable so I can use it for other things.
Using the Split function, I can get any part of the array between the delimiters (""), but what I'm trying to do is get all the information after the LAST delimiter in the string.
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Apr 16, 2009
I'm developing a management program for a driving school, where information about all students is stored and accessed.
The thing is, this school has got two branches, so I need some way for those two computers to share files with each other in order to keep a common database. I would like to use the same program in both computers, to keep simplycity to the maximum.
I know it's using TCP, but I haven't got the lesser clue of how i can achieve that. I've looked around, but I haven't found much of how to acchieve something like that. The files both computers would be sharing are text files.
About the IPs, I'm thinking of using NoIP or one of those to always know both IPs.
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Jun 2, 2010
I'm tyring to pass a variable data type to a template class. Something like this:
frmExample = New LookupForm(Of Models.MyClass) 'Works fine
Dim SelectedType As Type = InstanceOfMyClass.GetType() 'Works fine
frmExample = New LookupForm(Of SelectedType) 'Ba-bow!
frmExample = New LookupForm(Of InstanceOfMyClass.GetType()) 'Ba-bow!
[Code].....
I'm assuming it's something to do with the template being processed at compile time but even if I'm off the mark there, it wouldn't solve my problem anyway. I can't find any relevant information on using Reflection to instance template classes either.
(How) can I create an instance of a dynamically typed repository at runtime?
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Jun 24, 2011
I have following instance of System.Collections.Specialized.NameValueCollection:
Dim UserSelection As New System.Collections.Specialized.NameValueCollection
UserSelection.Add("D_Color1", "Black")
UserSelection.Add("D_Color2", "Green")
UserSelection.Add("D_Color3", "Purple")
I need to save this instance to hard disk and then load it back from hard disk as an instance. How do I do that?
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Aug 4, 2010
D is a dictionary whose entry values are of Type T..What I'm attempting to do is have a delegate like "Serializer" below that I can invoke on an instance of T, such as "Entry.Value" below.Please see the "return Entry..." line below for my wishful thinking.[code]
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Aug 30, 2011
I am looking for a way to make my app running in a single instance mode and showing the MainWindow of the first instance when another instance is launched.I do a quick search on the internet but I did'nt find anything to open the MainWindow of the first instance or it was for Windows Form not for WPF.
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