Programmatically Can One Find A Control's Owning Thread?
Feb 13, 2012
It is a requirement that all .net Controls are created on the main thread, at least this is necessary if the intent is to integrate the control in with the interface which is usually the case. Additionally to modify properties on the control one must invoke the method from the control's thread using its own invoke method.
Is there a way to look at a control and identify its owning thread directly?
Additionally or conversely, is it possible to detect whether the current thread is the "Main thread"? Is there anything special about the thread that Visual Studio identifies as the main thread that can be seen at runtime, or is it simply that this is the first thread that VS executes to initialise debugging?
I have a simple WPF windows application trying to read a serial port with the System.IO.Ports.SerialPort. When I try to read the incoming data in the DataReceived event, I get an exception saying that I don't have access to the thread. How do I solve it?
I have this in the WPF window class:
Public WithEvents mSerialPort As New SerialPort() Private Sub btnConnect_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles btnConnect.Click With mSerialPort
The backcolor of a default DateTimePicker control seems to be Color.White, but can this change based on a users theme colours and how do I find out what it is currently set to?(There is no backcolour property and DateTimePicker.DefaultBackColor returns SystemColors.Control which is not actually correct)I guess that if someone can confirm that this can't change then I am safe to hard code it? The basis of this question was not actually a typo, it was the fact that BackColor does not show up in my DateTimePicker control intellisense.
In 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".
"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.
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
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.
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
When i run the program i am getting the following error in this line TextBox1.Text &= "File Created: " & FullPath & vbCrLf"Cross-thread operation not valid: Control 'TextBox1' accessed from a thread other than the thread it was created on."
I need your help on the following. In debugging mode only the program is stopping to the following line "My.Forms.FormMain.HelpProviderMain.HelpNamespace = "Reports.chm"" with the following error ""An error occurred creating the form. See Exception.InnerException for details. The error is: Cross-thread operation not valid: Control 'FormSplash' accessed from a thread other than the thread it was created on.""
I noticed that when I am putting NONE in SPLASH screen option in the properties of the project, there is no problem.I am no familiar with treating that's why can you give me detail instruction how to overcome this annoying problem?
In debugging mode only the program is stopping to the following line "My.Forms.FormMain.HelpProviderMain.HelpNamespace = "Reports.chm"" with the following error ""An error occurred creating the form. See Exception.InnerException for details. The error is: Cross-thread operation not valid: Control 'FormSplash' accessed from a thread other than the thread it was created on.""I noticed that when I am putting NONE in SPLASH screen option in the properties of the project, there is no problem.
As we know, one STA UI thread creats the controls only canbe accessed in the UI thread in Winform application. And we need to call control.invoke or begininvoke to run the code in the background thread.
Yes, below code in VB.Net , VS 2010 Winform project can throw the exception "Cross-thread operation not valid: Control 'Form1' accessed from a thread other than the thread it was created on."
My program crashes with the following error:Controls created on one thread cannot be parented to a control on a different thread.Purpose of the program is to add a control from a thread outside the main thread.Below is the code Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
Currently I'm using a third party file hosting website (like mediafire) to upload my program and I update the link every time a new version is out.I know there are some ways to autoupdate the program but most of them need to own a website, which currently I don't have.So I was wondering if there could be a way to make an autoupdate using sites like mediafire.Example: I always delete old version of the program, on mediafire when someone try to access a deleted file page he gets redirected on a page which says "file deleted or invalid". So if the program find out that the file link redirect to that page it should inform the user about the new version.
I have a VB.NET form created in VS 2008. This form contains an ActiveXControl (MapPoint 2006 Europe ocx) located and reference here:[code]The project compiles just fine. However, when I run this starting form I receive this error:An error occurred creating the form. See Exception.InnerException for details. The error is: Cross-thread operation not valid: Control 'AxMappointControl1' accessed from a thread other than the thread it was created on.[code]I mention that the very same project was upgraded from VS 2005 on which worked just fine.
I need to find the date of Monday this week programmatically.For example, for this week Monday was on the 9th, so the date I need is: 09/11/2009.And when we roll over to next week it needs to calculate: 16/11/2009..I have tried doing this myself but I can't see how to do the arithmetic.
I would like to a) programatically and b) remotely find out the last date/time that a user successfully logged into a Windows machine (via remote desktop or at the console). I would be willing to take any typical windows language (C, C#, VB, batch files, JScript, etc...) but any solution would be nice.
I am currently learning ASP.NET and I've been wondering if is possible to find a button that is in a Gridview and perform a 'Click' on it when the user clicks on another button not in the Gridview.
I am able to find out when is the last time a user log into a domain but I am also wondering if it is possible to find out what's the machine's name or IP.
In my Active Directory, I see there is an attribute called logonWorkstation but it seems not being used (no value stored)
I have a DataGridView with 3 columns (metric_key, metric_name, metric_value).There are for example, 6 ROWS in this table (6 different metrics), added programmatically (DGV is not bound in any way)
Now, when I assign values in my grid I do:
dataGridView1.item("Metric_value",0).value = "value of the metric in row 0, in the column named "metric_Value".
I want to find the application thread and invoke something on it ... the problem is i have access to NO OBJECTS on the main thread so calling object.invoke is not an option. This is because I am making a plugin for something and have no access to the existing objects on the main thread .
I'm in the Progress of changing a big Application from Singlethread logic to Multithread logic. I'm currently move Dataloading Logic into a sperate thread, and work with callbacks after they are finished. I have Synclocks in place in order to ensure threadsafty. But sonetimes the Synclocks wait even if there is no other thread with the same synclock active. Is there any way to find out what witch thread they are waiting for, and why? BTW, I have FW45 installed, may that be the reason, since it'S a inplace upgrade for FW40?
