I have been working on a small side project that will read in from a serial port and send off a email depending on what it receives. At the moment I am stuck with a problem of it telling me it cannot access the text box as it was created on another thread. Does anyone know what I can do with this error? I have tried using invoke statements but it does not seam to work. [code]...
View 2 RepliesI am an amateur to say the least, but I have made a few basic program. Anyway, I am making a dvd changing robot. The hardware side is already built, and works great with via the serial port. In order to make this thing work I am going to have to make a multi-threaded app, my first.
[Code]...
how to create a program that can access information held in an excel database and show it in a simple form.
View 2 RepliesI'm trying to update the UI from a background thread, but the method I'm using at the moment isn't working. From what I've been reading, the method I'm using should work, but it isn't.[code]...
View 8 RepliesI recently had some problems with the performance of the Word object model. In an add-in that I wrote for Word I need to parse through all the words of a document and replace some of them or ask the user for the ones that have multiple replacements. I know that it is faster to ask Word for all of the document text content at once and then process it and put it back all at once again, but this is not suitable for my add-in because I need to have access to the range objects that represent the words that have multiple replacements so that I can somehow mark them in the document and present the user with a tool tip from which he can select the replacement he wants.
So for the moment the single great speed improvement that came in my head was multithreading since most people already have dual core or better. The problem is that all the things you find on Google say that multithreading in Office is a very bad thing to do.
So is there any one who managed to do this in a manner that worked in most of its usage? By this I mean if it also worked on other PCs then the development one?
I 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 am using Synclock to prevent multiple threads from logging text messages to the same file at the same time, but this doesn't seem to work:I get frequent sharing errors on the logfile, within the synclock block.The Synclock is using the variable holding the filename, because it exists all the time and because it is always the same object, whatever class instance or thread I'm in.[code]Despite using Synclock and a Using block around the code, I keep getting this error in the sw.WriteLine(Msg) line:System.IO.IOException: The process cannot access the file '(filename)' because it is being used by another process.Should I use some other type of object than a string to synchronize on?I cannot use a user interface object (button or so) because it is a windows service project.It was written and compiled in Visual Studio 2008, but targeting the 2.0 framework because it has to be able to run on some old Win2000 machines.
View 12 RepliesI've just recently figured out threading, and how to use it. I was even able to figure how to make a background thread modify the text property of any form control that has a text property.
I figured if you could specify the name of the control whose Text property you want to modify, it could be done easily, and I was right[code]...
Is there a way that you could do this, but eliminate the need to specify the control type as a parameter and maybe have the application determine what control you're trying to use by it's name?
I am considering a piece of code that will manage access to a collection object from multiple threads - add, update, remove, clear. OK ... so I have put a sync lock within each method, but what is not clear from the MS documentation is exactly how the sync lock is behaving. Is it locking the piece of code it wraps? Or is it locking the object? And if it is locking the object a private static object should lock out any code locked on the object within all instances of the object? i.e. if an add operation is underway, an update, delete or clear will wait for the lock to be released.
Finally, if I have multiple threads contending for the sync lock, how is the release managed? First come, first serve? random (from my p.o.v)? Is there a chance that two separate threads could blunder into 'locked' code simulataneously?
I have a fair bit of experience with VB.NET and C# (In this case I chose VB.NET, blame my laziness), but I do most of my professional work using PHP. I have no experience what so ever in using any database with VB.NET let alone MySQL.Just FYI, at the moment I am only trying to Query the database to gather the information required to activate. The Activation wizard and algorithm building (which is finished anyway), and everything else will come soon. I chose the MySQL database because I have experience with it, and it seems the best option for remote usage.The whole idea already works in PHP, I'm just have major issues moving it accross into VB.NET (Using the MySQL Connector.NET);I understand the basics, and all I need to know how to do is Count Rows and gain access to the other information in a row based on provoided information (in PHP, through mysql_ result)
So, here goes nothing, this is the Query code I am using in PHP to complete the job I want to do in VB.NET. [code] As you can see, I basically need to get the PHP code into VB.NET to fit into the 'btnQueryDB.Click' Command in VB.NET. By Equivalent, the Product ID in VB.NET will come from 'txtPID' and similar, Serial Number will come from txtSNUM. Once counted to be 1, the Activation Code and Status will be fed into 2 other text boxes in the form. (acCode, and acStatus).
I am making an application which has a form that I have set a notify icon for, I load this form at startup and then hide it. Then I have another form that the user can load (from the notify icon) which loads and runs a sub on another thread using the following
Dim d As New MyDeligate(AddressOf ProcessReminders)
d.BeginInvoke(AddressOf RemindersComplete, Nothing)
When this is executed another notifyicon appears, and then when the form closes it stays. I also notice that the memory usage remains higher than when the form loads. How do I prevent this, I am not sure but I believe that by creating the new thread it recreates the initial form and then it is not destroyed.
Hi
I have a thread that it calling many processes.
While the processes are executed (spends some seconds or minutes in completing all the tasks) I show form "Please wait to complete all tasks".
But one of these processes I have to show a form because the user has to choose a few data. But the problem is that this form is showed minimized.
Already I have tried to show it maximized and to bring it to the front but it does not do it.
how I can show this form to front and maximized?
My actual code is:
f= New frmLPlantillas
f.WindowState = FormWindowState.Maximized
f.BringToFront()
If f.ShowDialog() = DialogResult.OK Then
value1= f.xxxx
value2= f.zzzzz
value3= f.aaaa
value4= f.bbbbbb
Else
Return False
Exit Function
End If
Thanks in advance.
I just made a rapid file transfer form for my photos.In which I drag photos into a listview with my destination folder set.I assign each individual file transfer to a new thread. This works very fast as compared to the standard drag n' drop.
View 2 RepliesWhen multithreading in VB, if you close the form while different threads are running, the process itself will not end. Is there a way I can force all threads to end, or end the process like in the Task Manager, when the form is closed?
View 2 RepliesI'm working on a Parental control
I have 3 questions:
1) How to detect a starting process -
Solved here
2) How to capture a copy of the process and look in all controls from all forms to see if the Text/Items property has offensive keywords
3) If yes, how to close them immediately. - myProcess.kill
Write your code as efficient as you can to reduce CPU load, to consume less energy and protect our planet from global warming.
using one form information to be transferred to a second form the code becomes invalid after an validation error has arisen from the first form (ie no adult passengers was selected and the error message was displayed) when corrected the information to be transferred become incorrect as the information is transferred without the correction. [code]
View 1 RepliesIn my program, I need to be able to access font file information like what the font's title is called, the styles it contains, etc. I am already able to access the font's file name and path and use that, but I need the other information too.
I've used a recursive file search of the fonts folder (which is how i got the paths and filenames), as well as using Dim oneFontFamily As FontFamily, neither of which seem to have what I need.
I need access to the information in a populated listview so that I can load some textboxes with the contents of the selected row.
View 2 RepliesI want to be able to get the table structure / design / column information from an access database. I have created a post in the Database/Access section with no luck, here, but I am wondering if I could achieve this through vb (2008 express edition) rather than the access sql query itself. My overall goal is to compare one DB structure with another, an integrity check if you will.
View 5 RepliesI've been trying to get information from a Access DB that I have added into VB 2010, the code is as follows:
Imports System.Data.OleDb
Private Sub login_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmd_login.Click
[code].....
Am using MS Access as my back end and I am having a table called "Dept" with 2 columns (dename & cname). In Vb.Net when I click a command button, all the data's of the first column should be displayed in ListBox1 and the Second column in ListBox2. I do not know how to proceed
View 1 Replieshow come the picture I have a ComboBox that has the names of customers. How do I get when I click the button "OK" appears on the client data: "Name, Mail and Telephone" in TextBoxes?
View 2 RepliesWhy couldn't I access some propery of the first listview and send it to the second? I've tried lots of different properties but none work. What about the ItemPlaceHolder or just User_Category? My thought is to to this with two ObjectDataSoureces and send the DataKeyName from the parent listview to the second ObjectDataSource. But I don't know how to get the DataKeyName (see the ???? below)
<asp:ListView ID="ListView1" runat="server"
DataSourceID="srcGetOrderForm"
DataKeyNames=User_Category
[code].....
How can I access the current user information via LDAP and VB.Net 2.0*? I found a vbscript that works, but I'd rather have it done in .net
Dim objSysInfo = CreateObject("ADSystemInfo")
Dim strUser = objSysInfo.UserName 'returns current user account
Dim objUser = GetObject("LDAP://" & strUser) 'queries active directory for user account
I'm using the framework 2.0 because it is for more likely in my XP/Vista/7 World to have 2.0 installed than 3.5 or 4.0
how do I access the information that the user has typed into my datagridview. In my case, I know I want the information stored in column 1 of the datagridview one row at a time.How can I get at this information?
View 1 RepliesI would like to try to make a program similar to Zune or iTunes. To do this, I need to access a music file's information (the kind which can be found in Properties>Details.) Can someone help me with accessing this information?My idea is to have the user open one or more music files and have their display names go into a ListBox, and when you select an item, TextBoxes or Labels would display the information. If I were to use TextBoxes, then I would like to be able to save the information if it is changed. I do not need help in actually playing the song, just how to access the information (i.e. Artist, Album Artist, Album, Song Name, Year, etc.)
View 4 RepliesI'm having a problem with loading my MS Access Database. I can get it to load but it won't load in a row. My friend told me to try this but it puts all the information in a column instead of putting all the information spread out accross the row.
Here's my code:
Dim lb_Connection As New OleDb.OleDbConnection
lb_Connection.ConnectionString = "PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA SOURCE = pass_database.mdb"
Dim lb_SelectCommand As New OleDb.OleDbCommand
[Code] .....
Also I'll attach an image of what the program does when I load it.
I was wondering if it's possible to access information from within Visual Basic about WIFI connections, such as their SSID, MAC address, ect. I don't know whether I have to add a reference, what commands to use, ect.
View 17 RepliesFirst, I would like to add a text box search field to this form (because navigating through several thousand users with arrows isn't going to work). When the search button is pressed, I want the username to be looked for. If found, the form (and each textbox, option button, etc.) is updated with that user. I can then modify the user's information and press save.
Second, how do I access and change information in a database with only code? For example, if I periodically want to check every user in the database to see if they have over "100 points" and if they do, I subtract 10 points from that user.