i AM TRYING TO USE A THREAD TO UPDATE SOME CONTROL during runtime using invoke and i get this message.here is my scenario:im trying to build a performance monitor tooli have a mainform that is MDI parent and i create mdi child using
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I have a filesystewatcher object. On it`s event it runs a procedure which fills a treeview with a data. I had problems with treeview methods, but when I run them using invoke method everything is ok. But I still have one problem. When I load the form for the first time, everything works fine. But, when I then close the form (me.dispose, me.close), and load it once again, when Filesystemwathcer start the procedure i have an exception "invoke or begininvoke cannot be called on a control until the window handle has been created" trying to run a treeview.invoke method?
View 9 RepliesI have a thread that loads a control from the database during a long running operation. If I close my window before that thread finishes, it throws a Invoke or BeginInvoke cannot be called on a control until the window handle has been created., when doing the Invoke.I've modified the code to look like the following:[code]However it still hits the Invoke line and throws the error. When debugging stops on the exception, IsDisposed is true, .Created is false, and .IsHandleCreated is false.how do i prevent it from running the invoke line in this situation?
View 1 RepliesI have an annoying bug which is very difficult to replicate. When I start my application, from time to time, I get this error message "Invoke or BeginInvoke cannot be called on a control until the window handle has been created". This makes the user think the application is unstable... I have no idea what could cause this problem. The application uses a splash screen. It's built in Visual Basic using VS 2010 and .net framework 4.
View 1 RepliesI show a waiting form (saying "Please wait...") on a different thread when there is long-running code in some forms (for example, during data loading). I show the form like this:
m_PopProcessingThread = New Thread(New ThreadStart(
Sub()
m_PopProcessingForm = New WaitingForm(m_Message)
Application.Run(m_PopProcessingForm)
End Sub))
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The stack trace points to the part of code where I hide the form. How could the handle not have been created, when just before the Invoke call, I loop until said handle is created?
I am trying to find the handle of the child window for the Yes button in the User Account Control window so i can click it. This window has a structure with a few child windows with the same name.
Dim hwnd As IntPtr = FindWindow(Nothing, "User Account Control")
Dim hwnd2 As IntPtr = FindWindowEx(hwnd, 0, "DirectUIHWND", vbNullString)
Dim hwnd3 As IntPtr = FindWindowEx(hwnd2, 0, "CtrlNotifySink", vbNullString)
Dim hwnd4 As IntPtr = FindWindowEx(hwnd3, 0, "Button", "&Yes")
There are multiple CtrNotifySink with its own Button child window or other child windows. How do i search thru the different CtrNotifySink window to find the one that contain the Yes button so i can send a click to it? I do need to find it before i can send a click, right? because i try just sending it to the main window with sendmessage and nothing happen.I even try sending it directly to the handle found by spy++ of the yes button with bm click but nothing happen?
I have been using a pretty slick generic invoke method for UI updating from background threads. I forget where I copied it from (converted it to VB.NET from C#), but here it is: Public Sub InvokeControl(Of T As Control)(ByVal Control As t, ByVal Action As Action(Of t))
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I have a (legacy) form where I had to add the InvokeRequired/BeginInvoke(Delegate) to avoid the "Control control name accessed from a thread other than the thread it was created on." exception.This seems to work fine but there are some scenarios where the BeginInvoke is not calling the Delegate (which I can tell from the output log). [code]
View 1 RepliesI am referring to this document on MSDN. I understand what ".BeginInvoke" does, however looking at the example code on the document.[code]The delegate myDelegate (and the DelegateMethod) accepts a control and a string, but, at the .BeginInvoke, a Label control is passed and an array.[code]Shouldn't a string be passed instead of the array? Am I missing something?
View 2 RepliesI have a Toolstripmenu with ten drop-down items in it.(named menu1, menu2, menu3 etc)
I have a sub with ten handles Menu1.click, Menu2.click etc.So clicking on any of the ten menu items calls the sub.But- how do I find out which one of the menu items was clicked?
I want basically:
foo = clickedmenuitem.text
I could do it with ten different subs but that would be a lot more code.Especially since the sub is quite large and I only need to know which item was clicked for a small part of it.
How do I find which of the ten handles for the sub was triggered?I tried handle.tostring but that gave the same string of numbers for each menuitem, that was clearly the wrong command.
Why is it when I call another VB program, it is minimized?
View 1 Repliesi have a small wp7 application with just a main page. The main page has 4 buttons and calls the ConnectionSettingstask for wifi, bluetooth, airplanemode and cellular data setting. I have also managed to create secondary tiles for any of these buttons. The OnNavigateTo event handles the secondary tiles using a key passed from the tile [code]The problem ia that when the user uses the secondary tile to call a task, the application opens directly the connection settings page, but after that the back key, instead of opening the phone main menu, open the main page of my application
View 1 RepliesHow can I get the handle of the window that is below (or behind, whatever you call it) the foreground window?
View 2 RepliesCan you look at my coding and let me know what I'm missing or doing wrong?I have a SSRS report that is called from a ReportViewer control and the ProcessingMode for this control is Remote. The report also has 1 parameter in it's DataSet.In the code I placed a MsgBox to make sure the code is finding the parameter and returning the parameter name. I am trying to stick the value of 10 into the parameter for playerID 10. Data for this player does exist.
I believe I need to add some more code to make this work but I'm not sure what else to add.
When the code executes the report is displayed but no data is shown in the report.
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I have created an application where from the starting class a modless dialog box is called. Once the dialog box is called then the program will close instead of waiting on the dialog box to call the appropriate functions.
A couple of notes: This was originally written in VB 2005, and I was successful by manipulating the automatically generated code for the starting and clean up for the class. I cannot find this section of code in my VB 2008 project.
I cannot start the program from inside the dialog box, since there are multiple dialog boxes and which one starts depends on what is currently running on the computer.
The program will run with a modal dialog box, but it does not function properly, so I must use modless.
Please help me to prevent the application from closing when it reaches the end of the code in the main subroutine. I want to have a function to explicitly close the application.
I've got the following code:
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The problem is that, when I call the "SetStatusBarText" sub from another thread, InvokeRequired is True (as it should be), but then my threads stall on the Me.Invoke statement - pausing execution shows them all just sitting there, not actually invoking anything.
I'm trying to add subs that will handle MouseOver events on textboxes that don't get created until after the program starts.
Each textbox gets created with a unique number attached to it like this...
AptTextBox0
AptTextBox1
AptTextBox2
etc...
Depending on how many are needed. But I never expect more than say... 15 at any given time.
Is it possible to handle MouseOver (or any events for that matter) if they don't exist until later.
I tried this but it didn't work....
I added this is the Designer code....
Friend WithEvents AptTextBox0 As System.Windows.Forms.TextBox
Friend WithEvents AptTextBox1 As System.Windows.Forms.TextBox
Friend WithEvents AptTextBox2 As System.Windows.Forms.TextBox
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But it doesn't do anything. I don't get errors, but apparently it's still missing something to properly handle the events.
Handle EventArgs on Variable or Not Yet Created Controls
View 2 RepliesI have created a PictureBox array to hold 104 playing cards that are all visible at the same time.I did this with this line in the declarations:Shared Card(104) As PictureBox
And with these lines in the Form_Load module:
For I% = 1 To 104
Card(I%) = New PictureBox
Card(I%).Name = String.Format("Card{0}", I%.ToString)
Card(I%).Size = New Size(71, 96)
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I have been successful in creating the array, positioning each and entering the images for all 104 PictureBoxes, but now I want to add code for the event "MouseDown.I copied the code for this event from my VB3 program and VB10 automatically updated the list of parameters, but nothing has linked the objects (Card) to the code.
I have tried to append "Handles Card.MouseDown" as well as several variations with brackets to indicate that it is an array.Auto-complete doesn't include "Card" as an option, and of course, since the array was never an object added to the form design, I can't create the empty module from there.
I would like to be able to hide the batch window which is called in the else statement and calls a batch to copy files from a server. I have seen some answers but I have had no success implementing them.
On Error Resume Next
Const ForAppending = 8
Set objFSO = CreateObject ("Scripting.FileSystemObject")
Set objVBLogFile = objFSO.OpenTextFile("C: empVBLog.txt", ForAppending, True)
strComputer = "."
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1. On the main form a scanner class is instantiated that (in the scanner's constructor) sets the scanner settings (baud rate, parity, etc) and opens the scanner for use
2. A barcode is scanned (via a scanner connected to the device in a seral port) while on the main form
3. In the scanner class, the DataRecieved event gets the needed info from the scanned code.
4. Then that info is passed back to the main form to a method RunCommandCode (which takes the scanned info as an argument)
5. On the main form the RunCommandCode calls another method CommandCodeHandler, passing the scanned info again
6. In the CommandCodeHandler sub a method is called in a Utils class (SetSelectedTab), which interacts with the form itself (determines how many tabs exist on a tab control), which is the reason for the invoke in the first place
So, before I figured out I needed to use the Invoke method (and, more specifically, that the scanner was working in a different thread), I was getting an error in step 6 on the line that got the TabControl.TabPages.Count.
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I am trying to get the handle of a window to get it's title text. I tried the WindowFromPoint, but it will get any control, not just a window. How do I get the window that the mouse is over?
View 9 RepliesIf you open several FullTilt games table, you can see that when on a table is required action it jumps automatically in foreground, BUT WITHOUT TO BE ACTIVATED, so that it title bar is grey and not blue. The window is the top window for my eyes, but it is not active.Now the question is: how to get the Hwnd of the topt VISIBLE desktop window (the window that is over all the other windows), also if it is not the active window?I can't use the GetForegroundWindow Api, becouse it gives the Hwnd of the top ACTIVE window...
View 9 RepliesI have a handle to a window using the FindWindowA() function in the User32.dll (Windows API) and I would to get focus on that window at a later time in my program. how to do that with either a .NET function or User32.dll function? Is there a totally .NET way to get the window handle and focus?
View 2 Replies<DllImport("user32.dll", SetLastError:=True)> _
Private Shared Function SetActiveWindow(ByVal hWnd As IntPtr) As IntPtr
End Function
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I'm trying to make use of some functionality from an external app in my program.
My problem is this:
My program manages to start the external app correctly and I can even get the WinHandle correctly if I don't use "ProcessWindowStyle.Minimized" when starting the app.
If I start the app minimized, WinHandle = ProcID.MainWindowHandle returns a 0 and as I understand it, it's
because the app is hidden in the system tray.
How can I start the app minimized and then get the window's handle once it has been minimized?
I've tried various functions like FindWindow and BringWindowToTop but none of them seem to work.
I am following some instructions that apparently work with vb6, but as i have downloaded the lastest version of visual studio i think its up to version 10.
The code i am trying to make work is,[code..]
I searched a bit for an equivalent.
I am following some instructions that apparently work with vb6, but as i have downloaded the lastest version of visual studio i think its up to version 10.[code]The error is that hWnd is not a member of windowsapplication1.form1.
View 3 RepliesI'm using a third party dll for my project and one of the function that is provided by the dll use form handle as one of the argument. But when i call the function, I'm not using any window form and it's just called from another class. So what value i should put for that argument?Here's the example of that function:
AVS_Measure (device_handle, form_handle, no_measurement)
After this function has been called, it will send message to the form_handle argument whether the measurement data is available and valid.I called this function from another class just for triggering start measurement and i have another function to retrieve the data. I do not have any form associate to it, what value i should put for this argument?
I'm writing a DLL library that interfaces to a USB device using winusb in VB.NET.
Since it's a DLL, I have no window, and it's possible that users of my library will also not have a window (command line apps, for instance).
The examples I've seen that detect device attach and detach all use RegisterDeviceNotification which requires a window handle to receive the attach/detach messages at.
How do I receive these messages directly into a function without a window to get a handle from?
I have the below code. When I execute this code, the handle is different between the Load event and the Shown event. I thought the handle was static for an instance of a window. What could cause the handle to change? The only other thing the form is doing is setting itself to invisible and setting the ShowInTaskbar = False in the Activated event.
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