This is a very simple piece of code involving threading and events. I am just refreshing the old grey matter as I find myself off work sick for a period of time.
Code:
Imports System.Threading
Imports System.Threading.Thread
Module Module1
[CODE]...
My application need to communicate with my self made device through serial port. I have to change the selected index of Tabs when I press a button on my device. I have Form1, Form2, Module1 Form1 Contains the Serial Port Control. Form2 contains the Tab which needs to be changed. When I press a button on device them, the button pressed is stored in an integer form in a global variable.The Interrupt for the Serial Port directs the control to the module1 where I decide using Select Case that what index of which TabControl I have to select.Depending on that, I change the Index of the required Tab.
PROBLEM:cross thread exception is fired as soon as the control reaches the statement where I Modify the SelectIndex property from the select case at Module1.While, on my other PC, the SelectIndex property is changed, but the next tab is not shown.
BUT, if I put all this code in a button control, and try to activate from there, then it works perfectly. However, I have to navigate through the tab controls using my self made device.I searched a lot on net and came across a solution which describes that we have to use delegate function and invokeRequired methods to ensure that the procedures run on the same thread.I am not able to decide that where exactly shoud the code for delegates and all be written, in form1, or form2, or module1.Also, in the hit and try that I did, I always got the value of InvoleRequired as False.
Here is the part of Code that I wrote for Delegates
Code:
'Form 1 is BLINDHELPER_SIGNIN
'form 2 is BLINDHELPER_USER
' I have defined these at Module1
Public Delegate Sub DeleToManageTabs(ByVal tb As TabControl)
Public Sub manage_Tabs(ByVal tab As TabControl)
MsgBox(tab.Name)
[code]....
After using this code also, there is no change in working of my application.
How can I execute a piece of code at set intervals without using functions or timers?
View 3 RepliesI spotted this ina piece of code I am trying to decipher, and it made me giggle...
Public Const INFINITE As UInt32
Infinity in an unsigned 32-bit Integer.
I'm currently designing an assembly that will be used by third parties. One of the classes has a long process of TCP connections and it informs about its process using events. For example
''# Do stuff that takes some time
RaiseEvent CompletedFirstPartEvent()
''# Do stuff that takes some time
[Code].....
What I've seen if that if the handler of one of those events takes too long (or even worse, it blocks) I can have timeouts and it's hard for the developer to see that one class is not working fine because his handler is taking too long.
I was going to fire the events in a new Thread to avoid this issue but this looks strange to me because I've never seen something like that, what I've seen until now is the developer spawning a new Thread if his handler was going to be timeconsuming. So the question is:
What would you do? Create a new thread or force the user to create his own thread? (Or is -there a better approach that I don't know?)
On this piece Of code I want to multithread, beginning where the for loop takes the data out of the array arydata. The threads would all do the same task.
View 1 RepliesI am translating a piece of C# code into VB.NET using online convertors..[code]The VB.NET translation is not up to the mark and gives compiler errors Any VB.NET expert who can suggest what to change to make the code compile?url.
View 10 Repliesmy situation is this; I have a search button which searches records with Surnames, when two or more records have the same surname, the first record appears and 4 navigational buttons appear, they are 'Go back to first record' (btnFirst), 'go back one' (btnPrevious), 'go forward one' (btnNext) and 'go to the last one (btnLast)'. All of these work properly except for 'go back one' (btnPrevious). When I click this and the record is currently the first one, the program crashes. Its probably a very elementary mistake but I can't figure it out. Here is the code for btnPrevious
[Code]...
Having read the rules I don't have much code to show apart from these lines I want to have executed just before the program or a form closes.
If My.Computer.FileSystem.FileExists("File.file") then
My.Computer.FileSystem.DeleteFile("File.file")
End if
How can I get the time that a piece of code toke to execute ?
View 3 RepliesI am starting to debudg my application in depth, and have realised that at certian points, if you close what appears to be the only open form, the application stays open. I was just wondering if there exists somewhere, a list of all open forms that you can view during debugging?Alternatively, is there a quick piece of code to close all non visible forms?
For Each frm In Application.OpenForms
frm.Close()
Next
Doesn't seem to work
I have a standard scoring algorithm but I need to help on a piece of code to only execute the scoring algorithm at certain times.I want it to be triggered by dates, but the problem arises if the program is used after 2 (or more) dates have passed, the first date will not be added as the second date is the newest and therefore the one that triggers the scoring algorithm. - The scoring algorithm gets the scores for that week, which are stored in a text file.
View 5 RepliesI have a piece of code which loads either french or english text and 2 link buttons that allow to switch between.
<%
if publierFR = 0 Then
if publierEN = 0 Then
[code].....
I am trying to insert a piece of html code into a web browser control in vb 2010. i have tried the webbrowser1.documenttext function but cant seem to get the browser to run the html code.
View 7 RepliesI am trying to make a blackjack program and I need to execute a different piece of code each time a button is pressed by the user.
View 5 Repliesi am getting a piece of text from a webpage, but i would like to only let the text after a $ to show up?
View 1 RepliesI am trying to successfully multithread a piece of software I have been working on. I have an array of threads 'gen' already working, calling to a method taking a single integer as a parameter (done via typecasting).Now in this thread, when the function gets processed (for each thread a roughly 500 iteration while loop) the index seems to be getting mixed up. As far as I can tell, my threads are messing with eachother and warping values. Now this is happening in locally declared variables inside this function, not global variables.It may be useful to know that I am using a WebRequest via a call to another method. Don't know if that makes a difference or not.
View 7 RepliesI came to a company that already has a fully grown project... but coders that worked here before me didn't follow conventions and didn't use parametrized SQL queries... as a result there is over 1000 places in a very huge project that can possibly be vulnerable to SQL injection...
I need to find a solution that will automatically detect if there is an SQL injection in the code. So, for example there is a form which allows user to enter comments regarding a product, which will be sent to database on submit... how can we make sure that a user didn't enter a harmfull query instead of a normal text?
Is there any advanced code/regular expression/magic that can detect if this text contains a piece of SQL query instead of normal harmless text? I will accept any links, pieces of code in any language or even commercial software that will do that for me.
How to I run multiple threads in VB.NET? Say I need 2 threads - one that prints 100 numbers in a loop and the second one that asks for the user's name and prints it inside a message box.
View 1 RepliesI have a database called "IMYS" and a "Customers" table in it. What I want to do is: Define a variable like "Last_Name" and retrieve last names of customers one by one. I've tried this before (and, it doesn't work for me):
===
Dim Last_Name as String
Dim I, K as Integer
Dim CustomersTable = New IMYSDataSetTableAdapters.CustomersTableAdapter
[Code]....
I use a simple for each loop toi grab a piece of data from a regex like:
[Code]...
I'm trying to sleep a single thread of code, when i try using System.Threading.Thread, it freezes the whole app, i need it to just freeze a portion of code.
View 11 RepliesI'm looking at implementing a piece of software I've created into a new environment. It is currently accessed via network share by users who have full administrative permissions on their user accounts. These same users will have their accounts locked down excessively. I am wanting to consider now before any changes have been made, any code changes I will need to make as my application makes use of a lot of features that admin users take for granted such as registry editing. My program is running through the .net 3.5 framework and is being accessed on XP machines.
View 5 RepliesI just had a new, last-minute idea on to take on a task, so I am running to StackExchange for quick help.
What I want to do is execute a series of methods right in a row, each in their own threads. I want the application to wait until all of these threads are completed, after which the program will resume. It also has to use managed threading (thread pool).
What quick examples could you provide to help me along the way? If it's too complex, what things should I know about so that I can Google it on my own?
I have a main thread which is designed to be a batch processor - it spawns a series of 'child' threads from a loop (which can vary in terms of the no of items) - see below
[Code]...
However, each of the 'child' threads could take anywhere from milliseconds to about a minute to process - depending on the complexity of each calculation. There may also be a large number of child threads - e.g 100s. Creating large numbers of child threads is not efficient. I therefore want some way to effectively queue each child thread (and cancel if the process is taking too long to complete). Autoevents seems like one way of doing this, but the only examples I can find seem to assume there are two different processes on seperate threads, not one process being repeated.
I'm trying to, from a client-side piece, call off to a server-side piece. I need to do this synchronously. On my server-side code, though, I'm calling off to another piece of code, which I want to have a maximum of, say, 10 seconds to return a value. If I don't have a response within 10 seconds, I want to force my own server piece to set my result equal to 0, and return to the client.
Here's what I have on my server-side code so far:
Public Function GetWebResult(ByVal inputParameter As Object) As WebReturnObject Implements IWebInterface.GetWebResult
Dim result As New WebReturnObject
Dim webItem As WebItem = Nothing
[CODE]...
I realize this code is not functional. The problem is that I'm unsure how I would go about getting back into GetWebResult to set the appropriate return values before it is sent back to the client.
I have this code and I know that this part "WHERE dbo.tblenrol.SectionName=dbo.tblSection.SectionName)" of the code not right... I want to update the my tblenrol.Adviser from tblTeacherFile.Adviser if the tblenrol.SectionName is equal to tblSection.SectionName...How do I do it??
Using cmdUpdate As New SqlCommand("UPDATE tblEnrol " & _
"SET tblEnrol.Adviser = (SELECT dbo.tblTeacherFile.Adviser " & _
"FROM dbo.tblTeacherFile " & _[code]......
I currently have the following working[code]...
What I would like to do is expand the filter to include alternative file extensions (i.e., ".rar", ".7z", etc)
I am making a program that takes files (inside their folders) and copies them into a selected file path. For example, I plug in my jump drive, run my program and it copies my files on the jump drive over to my PC. Now my program does this but it takes the files inside each folder in my jump drive instead of creating a folder for each one in my jump drive. The result is a mess of files in the selected pathway in my PC.I went and created variables in My.settings so that you can save the file path even after you close the program. I just want the program to copy the folders(with the files in each folder) in my jump drive and move them over to my PC.I am using this program copy the files from my jump drive over to my PC, because I save a lot of work on my jump drive and I need to back it up often. [code]
View 4 RepliesThe bigger problem is that I can't seem to get everything involving using stream writer and reader working. If I start of with a .txt file already correctly formatted then I can display it in the list box. But adding data during run time is not proving successful.
[Code]....