What I do is I have a variable on form1 and its an integer which has a value on load of 0 and named count.When I click the 'doSomething' button it is increased by 1 and when I use the function 'msgBox' I get to see 1.After that I start a thread which is going to look up count but when I check the value there is 0.
View 22 RepliesAfter many searches i end up using this class for global keyboard hooking. Link: Global Hook post [code]My app is performing operations that take some seconds to complete (ftp upload small files on interval), and during this time the hook lovks the keyboard. This i dont want of course..I cant jump to Async FtpWebRequest right now because it needs many changes, so i thought that the solution would be to make the hoook live in another thread.A proposal is to move my time - consuming operations (upload) to another thread.Upon doing this i am facing other problems. Because the time consuming task (upload) is in a timer i would have to rewrite a big portion in order to synchronize the file->save with the file->upload and i dont mind the app locking for 3-4 secs. what i do mind is to loose the kayboard for 3-4 secs.
View 2 RepliesIm creating a service for a mobile platform and I need to process user messages on a different thread than they were created on to leave the threadpool open.Anyway my App will be using a MySQL database and when it gets a message it will add the message to Another thread pool. But in the sub that procceses the messages I will need to perform query's on the database. So i know i can use a global variable and it will be visible to all threads but is making database operations safe while using a thread pool with a global mysqlconnection?
View 2 RepliesI have a hardware which sends out packets containing 17 bytes to the comport in bursts of 3. the little test VB that I have written receives and displays the bytes in a line of 17 bytes long and works fine until it gets to around 170th packet, then it starts to mix up (looks like shifting the data left) the bytes shift mostly by one digit sometimes by two. then it will continue to give almost a packet correct and a packet shifted for about 50 packets. Then it will correct itself for a long while, but then the speed at which it receives drops. All the packets are sent 3 times, and before things go wrong (within the first 170 packets) the packet counter shows that it receives 3 packet each time but after the problem it goes to 2 packet per burst and then to one.
If i close my VB monitoring program say at packet 165 and immediately open it again, it wont go wrong for another 170 packets, this points the finger at VB. I have check my hardware, there is no problem with that.The program reads port - waits for 17 bytes - once 17 has been received it will go and buffer the packet in an array. In fact they are 2 arrays but printing fro either results in the same problem.I have tried whatever i could think of but to no avail, i am wondering if some kind of house keeping needs to be done to clear something... I am sorry the program is a bit messy but I have been making many changes to find out what the problem is - my code below:[code]
I have an object that is defined as a global variable based on custom class. Within that class I have an event that gets fired a certain intervals. These events are fired on the same thread as where the object is declared. How do I create a global object, but have the events within that object fire on a separate thread?
View 2 RepliesI'm currently finishing up a project that reads / writes to an access database. The only issue I'm having is that it needs to have the file path to the database file. EX:
[Code]...
Is there a way to rotate a label such that it reads vertically? I've checked all of the label properties but there doesn't seem to be one that will do the trick.
View 1 RepliesI have to make a program that reads a txt file after reading it, show it in a richtext box and in another tab make the average of the grades the input received sort it by the student id and then in the same rtb sort it by the average of their grades, and finally save it on a new text file.
The text file input is something like this
12 3 10.0 6.9 7.3
19 2 6.7 9.3
10 3 4.5 9.3 4.5
[Code]...
As you noticed in the input the first number is the student ID, the second number is the number of tests made by the student, and the other 3 numbers are grades, in the output the first number is the student ID, the second number is the average of the tests, and the other 3 numbers are grades, I don't have a problem opening and saving a text file and neither creating a tab with 2 RTB , my problem is how do I tokenize or read the input line by line, i guess that i need to use the split function but I don't know how to implement it into the program.
I am making a program that reads a file. Csv,and information to a textbox.
After he demand on the Csv file, the same information he writes what is in the same row forward in the same textbox.
A-dos-Francos;39.346246,-9.031105
A-dos-Negros No;39.366089,-9.090929
A-dos-Negros PV;39.366886,-9.131098
[CODE]...
Example: If "A-dos-Francos" is written in the textbox I want that it be replaced by "39.346246,-9.031105"
But in the same textbox.
Im trying to do this
[Code]...
But it will just skip to the last status (Label3.Text = "Status: Welcome")
im trying to terminate a threading.thread using thread.abort the thread runs a download connection so is usually in the middle of socket.recieve or socket.send or socket.connect when aborting i just want to terminate the thread no matter what thread.abort raises an MDA excpetion. so i ticked it off in the debug exceptions menu. now it doesnt raise an exception, but the thread simply wont terminate. my program wont close unless i press top in the debugger.i cant pause downloads because i cant terminate the thread this code wasn't working?
Dim vT As Threading.Thread
For Each vT In clsDownloader.DownloadThreads
If Not vT Is Nothing Then
vT.Abort()
[code].....
as for the exception concerning threads being aborted from other threads being dangerous, how is it possible to send a message from a main thread to another thread to abort itself? as far as i know the only way to a abort one thread from another is to just kill it (because i dont know of ways for a thread to communicate with another).
evrytime i add new controls to a form in vb.net the designer regenerates code and asks me to make corrections, so i have to keep on changing the object declarations to global using the 'global' keyword evertime it regenarates code,especialy dataset objects.how can i prevent this?
View 1 Repliesi could use Global x as string in vb6 in a module to declare it with global privelages, how can i do this in vb2008? how to declare a global variable in vb2008? so that i could use it anywhere i want. i know global variables are not recommended in programming but i need one.
View 4 RepliesI'm firing a thread to unzip a file. I need some way of indicating to the parent that the unzip thread has ended. I've tried raise event in the unzip thread to a sub in the parent but this runs the sub from the unzip thread. With ApartmentState set to STA, so that I could use a save dialog, this was OK until I displayed a messagebox which was hidden behind the main UI(and whatever I did I could not get it to the front).
View 11 RepliesIn one application, I need use 4 simultaneous threads.When the threads finished, I need to update the text of a TextBox.So, I create 4 Textbox, and I wanna the threads change the text to FINISHED.Each thread change one distinct TB.I use this "example"
Dim Terminados As Integer = 0
Private Sub frmEnviarMensagem_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Timer1.Enabled = True
Timer1.Start()
[code]....
The problem is, I have an error in the red lines.The error is: INVALIDOPERATIONEXCEPTION "Cross-Thread operation not valid: Control tbPlaca1 Accessed from a thread other than the thread it was created on."I don't use cross threading. Each TB only was accessed for the correspondent thread, and for the "main program".
This is the error message I am getting:
"Cross-thread operation not valid: Control 'Panel1' accessed from a thread other than the thread it was created on." The reason I am getting this error is because I am opening up a new form and then calling these three things:
Panel1.Show()
Label1.Show()
Label2.Show()
why I get this error message because it doesn't occur normally if I open Form2 after closing Form1, it only occurs when I open Form2 after closing Form4.
I have done a program using vb2005 to display reading from my microcontroller bs2 board but have encountered some problems. My code are as follows.
Dim Stop_Rx As Boolean
Private Sub btnRead_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRead.Click
SerialPort1.Open()
[code]....
I've encounter an error which is, (Cross-thread operation not valid: Control 'txt1' accessed from a thread other than the thread it was created on.)
When my client try to connect to server I'm getting this error : Cross-thread operation not valid: Control 'l_users' accessed from a thread other than the thread it was created on.
Private Sub _socketManager_onConnectionAccept(ByVal SocketID As String) Handles _socketManager.onConnectionAccept
l_Users.Items.Add(SocketID)
End Sub
Would anyone be able to help me here please. I'm fairly new to VB.net and threading so im just trying to figure out what is happening.When I debug this I am getting the error thread operation not valid: Control 'ProgressBar1' accessed from a thread other than the thread it was created on.
I'm a little lost as to why the error is occuring or how to fix it. I've had to put the progress bar in a separate thread otherwise the GUI crashes
[Code]...
My understanding is that thread.join will suspend the execution of code on the calling thread until the spawned thread finishes or is aborted...
With that in mind, I tried this:
For i = 1 to 50
threads = New Thread(AddressOf test)
threads.IsBackground = True
threads.SetApartmentState(ApartmentState.STA)
[CODE]...
However, the rest of the code runs when the loop finishes, not waiting for all the spawned threads to finish. Since the rest of the code needs the threads to finish (otherwise the rest will error).
I have written an application that loads a form - frmCad as well as AutoCad. It does this via a class which detects when AutoCad quits.
Friend Class CadApp Private WithEvents AppObject As AcadApplication... Private Sub AppObject_BeginQuit(ByRef Cancel As Boolean) Handles AppObject.BeginQuit RaiseEvent Quit() End SubEnd Class
My main class loads frmCad as well as CadApp.
Public Class Cad Private WithEvents frmCad As CadForm Private WithEvents app As CadApp... Public Sub ShowForm() If frmCad Is Nothing Then frmCad = New CadForm frmCad.Visible = True End Sub... Private Sub app_Quit() Handles app.Quit frmCad.Dispose() frmCad = Nothing .... End Sub
When I debug the program, it stops at frmCad.Dispose()The program continues to execute, but all the code after it fails to work.Looking more carefully I get an error message which contains:-Cross-thread operation not valid: Control 'Autocad' accessed from a thread other than the thread it was created on.
My error:Cross-thread operation not valid: Control 'label2' accessed from a thread other than the thread it was created on. I want to be able to give my Public RunBot() sub access to edit Labels, buttons, etc without an error.
[Code]...
I'm getting the 'System.InvalidOperationException' error on acccessing a thread from other than where it was created. My code is:
'Required by the Windows Form Designer
Public components As System.ComponentModel.IContainer ' changed from private
[code]....
My problem is Cross-thread operation not valid: Control 'statusHO' accessed from a thread other than the thread it was created on.
System.InvalidOperationException was unhandled
Message="Cross-thread operation not valid: Control 'statusHO' accessed from a thread other than the thread it was created on."
Source="System.Windows.Forms"
StackTrace:
[Code]...
i used it and it works fine then. but as it is mentioned its not a good practice to use it. So what should i do? is it ok if i use this as i am not able to use correct practice. Mine application is not for enterprise purpose. its just my class project, and it works fine even if i put application working in background. System works ok. I dont know how to correct this error.As i dont have that much knowlege of threads.
So please guide me how to fix this in correct way otherwise i am force to go for bad programming practice
Please refer to Windows Mobile Developer Center > Smart Device Development Forums > Windows Mobile Development > Appendtext not working for all my code details
Cross-thread operation not valid: Control 'lv1' accessed from a thread other than the thread it was created on.
Dim lvi As ListViewItem
For Each lvi In lv1.Items
[code]....
I have this little code here in vb 2008, I created a flag var to see if the user has clicked the button "enter" so the flag would be set to true. If its true then the game would begin...
I have a label that says "Press enter to Play", and if the user presses play the flag is true, the label visible is set to false. I have the keydown event to check if the enter button has been pressed, i checked if it works and it does, but the var of the flag is always false in my other subs...
Thats the thing with vb i dont understand is when you make a public variable, and when you change the value of the var in a sub, it doesnt change globally.
CODE:
I don't really know how to call this...Anyhow... I have two objects (for example, "A" and "B") of the same type/class. I have an event (for example, "Refreshed") in both objects. Is it possible, that when "Refreshed" fires in "A", it also fires in "B"?
Edit: forgot to mention - "A" and "B" don't "know" each other.
Ok i have a Form with the following
Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
txtNotepad.Text = LoadFile("notes.txt")
[code].....
Okay, Im a newbie to VB, so how do you create a Global variable inside a sub.
View 6 RepliesI would like to get the global ip of the pc running the program in VB and echo the ip into TextBox1
View 20 Replies