Using The Threading.Overlapped Class As A Parameter For A CreateFile Call To Enable Termination Of IO Operations
May 15, 2009
I'm attempting to communicate via USB to a hardware device. So far I can use CreateFile, ReadFile and WriteFile to communicate with the device efficiently, but occasionally the WriteFile call will hang because there is no device located at the port where it was installed. I have the WriteFile and ReadFile calls in a managed thread that I use the Join() method on to return control to the parent thread.
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Oct 27, 2010
I'm using Visual Basic 2010I've created a ListBox and a BackgroundWorker using designerI want to change the location of listbox using backgroundworker but I get the error as follows:"InvalidOperationException was Handled by user code:"Cross-thread operation not valid: Control 'ListBox1' accessed from a thread other than the thread it was created on
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Mar 16, 2010
What do I want to achieve: I want to perform some time consuming operations from my MDI winforms application (C# - .NET). An MDI child form may create the thread with the operation, which may take long time (from 0.1 seconds, to even half hour) to complete. In the meantime I want the UI to respond to user actions, including manipulation of data in some other MDI child form. When the operation completes, the thread should notify the MDI child that the calculations are done,so that the MDI child can perform the post-processing.Should I use explicit threading (i.e., create explicit threads), thread pools? Or simply just propose your solution. Should I create foreground or background threads?And how does the thread communicates with the GUI, according the solution you propose?
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Mar 21, 2009
I'm Trying to Call the Stored Procedure which has one input Parameter and one output parameter . VB.net code is below
[Code].....
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Jul 16, 2010
I have a vbscript that runs under asp page. I need convert the code to VB.NET
SET objCommand = Server.CreateObject("ADODB.Command")
objCommand.ActiveConnection = Application(DB)
With objCommand
[code]....
What is the VB.Net that will do exactly the vbscript does? I like paramer(0) and 1 and 2 etc since I don't need to define the parameter(0) as integer or varchar etc. I remembered I have discuss this before and it is possible to do in VB.NET?
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Sep 29, 2009
How would I test the following code?
Public Sub SetSerialIdForDevice()
Try
Dim component As Object = container.getComponentRef("componentInterface")
[code].....
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Sep 11, 2009
Dim a as Type=GetType(className) would gimme the type. But I have only the name of the class as string. I want something like GetType("class1") which would return the type.
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Aug 24, 2009
threading in diffirent class?? I get an example like this
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim NewThread As New Thread(AddressOf Counter3)
[code]....
a thread at example above was written in one class, now how to make a same thing like that with a different class?? and one more thing if you click the button twice then it have two proses.
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Apr 17, 2011
I have some code I've written that has worked sporadically, and I don't understand the reasons why it succeeds or fails. The code in question is fairly straightforward, a single call to CreateFile() from VB.NET;
Dim Handle As Integer = Win32.CreateFile(KeyboardPath, GENERIC_READ Or GENERIC_WRITE, _
FILE_SHARE_READ Or FILE_SHARE_WRITE, Nothing, _
OPEN_EXISTING, &H80, 0)
The problem is that when I call this, I get the win32 error ERROR_ACCESS_DENIED, but if I remove the GENERIC_READ request, the handle is granted just fine. This has happened before (on a different machine), and I'm completely stumped as to what sequence of events would result in the ability to write to a device and not read from it. The device in question is a Logitech G510 keyboard, and this code has worked fine before on a Vista 32-bit system (I'm now testing it on a Win7 x64 system and fixing all the compatibility issues I can find).My question is, what can cause CreateFile to sporadically fall back to only allowing write access, what am I doing wrong that's causing it to do so, and how would I go about fixing the issue? I've included the full function below - note that with ONLY the GENERIC_READ flag passed, I also am not allocated a handle (same error)
As reference, the particular device path I've been using is \?hid#vid_046d&pid_c22d&mi_00#7&1a08be07&0&0000#{4d1e55b2-f16f-11cf-88cb-001111000030} (This is for a Logitech G510 gaming keyboard)
[code].....
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Aug 29, 2010
using multi-threading in my application.Basically what i am trying to do from within a form event is initiate a class instance and then run a function of that class (via a thread) that changes certain member values of that class.Those class member values are then used to update values on the main form.Ive created a simple example below but i cant seem to get it to work.The class values are not updating and im struggling to understand how this threading works.
Class FormMain
Private Sub BtnClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles myformbtn.Click()
Dim myFileCounter As New FileCounter()
[code]....
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Dec 8, 2010
Is BindingSource class makes use of Threading to read and write the values in controls and in objects?I mean how bindingsource know when properties of an object changes and sometimes seems not to know? Does it use a kind of BackGroundWorker running to watch changes on bindings objects? And why does it sometimes read and write properties so many times the same value on the same object's property?I found that it's sometimes easier not to use them since it's hard to know why a control do not update but, on the other hand, dealing with control events can be tedious. And what if i tried to make my own BindingSource Class not inherited from the System.Form.BindingSource
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Aug 17, 2010
Is it possible to enable XML intellisense in a C# class as it is in the VB editor? Similar to this article's prescriptions:
[URL]
Would like to not have to use xsd.exe to generate a class from the XML.
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Mar 1, 2010
I need to create unit testing project for my current website. The currentw ebsite si written in VB. All unit testing examples are using interface to create mock object. My current VB class does not implment any interface. Can I add interface and implement it to my current class and functions without affecting or changing codes to any pages in my website that call the functions? For examples my current class is like:
[Code]...
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Apr 22, 2012
Base class has one field to hold numeric balance value. With 2 methods that accept arguments for adding and subtracting the new input calculating new balance. Sub class has four fields dates, transaction, memo and amount.I have a deposit form, and withdraw form. Each time one transaction is entered it creates an object with sub class fields, then adds to the account collection. My problem is not understanding how to call the deposit/withdraw method and pass the current transaction amount back to the base class to alculate the new balance. Does anyone have any links to information/tutorials on how to perform something like this? As you can see with my code I have tried various different approaches without any success.
[Code]...
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Oct 21, 2009
I build two programs, 1 - bootstrap and 1 - mainprogram
now, mainprogram has 2 constructors, the default and the one which i defined and it accepts an integer the default constructor checks the variable named iscalled a type of integer to have a value of 1 or zero, if its zero then it should shows a message saying "Improper initialization" then exits..
What I mean here is, mainprogram should only run if its called by the bootstrap program.
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May 7, 2009
I have an application that used Macro.In this macro I would like to call an external executable like this:
SYSTEM( "C:ProgrammeTransform.exe" ,
"C:ProgrammeVectors.txt" ,
"C:ProgrammeVectors_Compensate.txt",
[code].....
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Feb 3, 2012
I have had some trouble on what to put inside the parameter named CallFWT as without it i would get a value of 0[code]...
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Dec 29, 2008
I wrote vba function in excel and I want to call this function in vb.net with parameter passing.
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Jul 31, 2009
in my SQL 2005 database I have defined this stored procedure:
CREATE PROCEDURE [dbo].[CheckOrders] (
@PK_Customer uniqueidentifier,
@Amount bigint OUTPUT)
[code]....
When I check the value of nAmount it stil contains the original value -1 the output value didn't return from the stored procedure although the number of records updated is 0 or more. The procedure was checked, it works and there are records updated and the value of @Amount is SET to a value 0 or more. I just don't get the values back. eventough the parameter @Amount is defined as OUTPUT. I also tried with outParam.Direction = Data.ParameterDirection.InputOutput instead of outParam.Direction = Data.ParameterDirection.Output . Same result. How do I get the value back from the stored procedure?
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Jan 15, 2010
In frmMain:
Private Sub DBReadAccountInfo(ByVal strAccountID As String)
Dim tmpaccountInfo As New PublicFunctions.clsAccountInfo
tmpAccountInfo.strAccountID = strAccountID
Dim ReadAccountInfo_Thread As New Thread(AddressOf tmpAccountInfo.DBLookupAccount)
ReadAccountInfo_Thread.IsBackground = True
[code]....
In "sub UpdateAccount", frmMain.InvokeRequired is always false. There's a MenuStrip control I'd like to update the .Text on.
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Apr 11, 2012
I have a SSRS report that contains a parameter called @playerID
what coding I need to add so the report can be run using the parameter?[code]...
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Dec 13, 2011
how to call a stored function in oracle through vb.net.From vb.net should i able to pass the values to arguments of that function without knowing the parameter names?Example: I have a function,Create or Repalce Function Func_Name(param1 Varchar2,param2 varchar2)
Inorder to call this function through vb.net, we need to give
parameterargs.paramtername="param1"
Is there anyway so that i cannot use the parameter name and call the function
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Aug 22, 2011
If a booking is present in database on 12/27/2011 at 5:00 pm for 2 hours and i try to make a new booking on 12/27/2011 between 5 to 7 pm then my code generates an error message. Even if i try to book at 4:00 pm for 2 hours it generates an error message as the 2nd hour will be overlapped here with already made booking from 5:00 to 7:00.
Now here comes the problem part. When day changes it doesn't generate error message i.e. IF a booking is there on 12/27/2011 at 11:00 pm for 3 hours then it should not allow new booking till 12/28/2011 2:00 am but when i try to book 12/28/2011 at 1:00 am it saves it in the database and doesn't generate an error message. I want an error message generated in such a case.
I am using two separate fields in database one for time and one for date. Both of them have DateTime datatype.
newtime refers to time on which i'm trying to make new booking addednewtime refers to time after adding the duration to time on which i'm trying to make new booking
[Code]...
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Dec 18, 2010
Why is last column of the listview being overlapped by the vertical scroller? How can i fix it?
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Mar 12, 2011
I have created a class for Socket reads so I can create sockets on command. Due to performing a socket read, the program will freeze waiting for incoming data due to being on a single thread. So I created a separate thread for the reading of the sock and attempt to invoke an event to prevent multi-threading errors.
But I am getting an error when trying to Invoke: "Invoke or BeginInvoke cannot be called on a control until the window handle has been created."
How can I fix this or is there a better way to read a sock without freezing the thread?
Class for Sockets:
Option Explicit On
Option Strict On
Imports System.Text
[CODE]...
Calling form code example:
Private WithEvents Socks As clsSock
Private Sub Sock_Connected(ByVal state As String) Handles Socks.Connected
MsgBox("Connected - " & state)
[CODE]...
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Mar 23, 2012
Is there a way to call functions within a class upon instantiation of that same class? Basically, I have functions within a class, but I want to automatically call some of those functions simply when there is an instance of the class created.
Basically, I have this structure:
Dim instance as new class
instance.function1
instance.function2
[Code].....
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Jan 29, 2010
I am creating a function and want to have IntelliSense pop down the list of valid options for a certain parameter in the same way that the MsgBox function behaves when you are typing your argument for which buttons you wish to include (such as MsgBoxStyle.OkCancel). I have done my best to search the internet but haven't found a thing which comes close to what I'm seeking. My monkeying around hasn't produced a satisfactory solution, yet, either.
A related additional thing, which I can live without but that would be nice to have, is the description of the current parameter, which appears below the function description as shown highlighted below MsgBox (Prompt As Object, [Buttons as Microsoft.Visual Basic.MsgBoxStyle = MsgBoxStyle .DefaultButton1], [Title as Object = Nothing]) AsMicrosoft.VisualBasic.MsgBoxResult
Buttons: Optional. Numeric expression that is the sum of values specifying the number and type of buttons to display, the icon style to user, the identity of the default button, and the modality of the message box. If you omit Buttons, the default is zero. This is my first post. I'm relatively new to VB .Net.
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Dec 4, 2010
I'm using a CheckGroup in a project found here. There were several things in the code that needed fixing to really be useful to me:The fact that the panel in the regular groupbox overlapped the checkbox control so that the bottom of some letters were being cut off. When changing the back color of the groupbox, it didn't change the back color of the checkbox. Fixing these two problems was easy, but fixing the second one led to a new problem. When changing the backcolor of the groupbox to Transparent, it also changes the backcolor of the checkbox to Transparent, thus displaying the text for both the checkbox and the groupbox's header.
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Apr 19, 2012
I have an application which I wrote in vb.net. When the application starts it connects to mysql database online to get some data and once done it proceeds.The problem is that at times it gets stuck in the mysql thing, I mean after requesting nothing happens and this causes my program to lock up. This can be because of internet problem or server.
Is there a way the program can determine that x seconds has elapsed and it has not got any data, so self terminate it. I tried using timer to perform this action but as the program requests for data, it gets stuck, I mean it locks up and thus timer also locks up and only after task is done everything resumes.
I wanted that when the program is about to start request, I can start a timer and determine that x seconds has elapsed, so now terminate the application.
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Jan 29, 2012
I have a Application that Crypts all Files in a Directory and the Subdirectories
Public Shared Sub CryptAllFiles(ByVal crypt As Object)
'check if this dir exists
Dim vDirInfo As New DirectoryInfo(vPath)
If Not vDirInfo.Exists Then Exit Sub
'get all files' sizes in current path
[Code]...
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