I actually have gotten the events firing like I expect except for trying to close the dialog window.
Background: I have a wrapper around my "Jabber Client" that sets the delegates for the client wrapper and basically generates a messageProcess event. This event is wired in the main program Class[code]...
I am currently developing a WPF application that will utilize existing WinForm dialogs. I'm experiencing a long lag between the time I call ShowDialog() on a WinForm to the time it is displayed.Even when reusing WinForm dialog objects the lag time is nearly as bad on the second hit. Meaning that the problem isn't in the constructor. have a work around to increase speed or know why the speed is so slow?
View 2 RepliesI have a winforms app with multiple GUI threads. I want them to be able to access each other's thread objects without having to keep track of that information separately.Is there a function in .NET that I can feed a winforms control or window object, and get back the thread? Or a function in the API I can pinvoke for the threadID?
Edit For those of you who for some reason believed my italicized text, congratualations, you're hired!! Here is the problem: "App is crashing in the wild by locking up totally, that is, it stop responding. Very intermittent, and trying to debug it, it seems to never happen."
So what do do? Install an option in the program that the user can activate under our direction, whereby from another GUI thread in the same app, do a thread.abort on the main GUI thread, then we can look at the call stack in the error log. Viola, found an impossible to debug error in less than a day. (Stop now, it had nothing to do with abusing multithreading:-)
I'll admit I almost didn't ask this, the reason I did was I could see an object reference to the main form, but there wasn't any for its thread. I'm giving Chris Shain the answer a/c it is a quick way, unfortunately when the thread is hanging, I wouldn't be able to do an invoke (it would hang too). A little more digging revealed the GetWindowThreadProcessId API call. But it's an unmanaged thread ID, apparently there are complications turning that into a managed thread ID.
So I bit the bullet and put in a global reference to the main UI thread. Would have posted it to begin with, but hadn't written it yet.In main public module/static class:
Public GUIThread As Threading.Thread
Sub Main()
[code]....
In main thread I create panel(s) (based on some configuration), and then in the next step based on the file type (like video, ppt, image...) I create appropriate controls (dynamically) to show on the forms.
The creation of the control will be done in separate threads (for each file). After creating the control, it throws an error when I try to add that control to the panel (which was created in the main thread), something like cross thread violation, control was accessed from one thread other that it was created.
Can some one please help me in this regard? In this scenario, everything - creating the panels and controls - will be dynamic. Nothing will be static.I tried some of the articles found here on StackOverflow (like, control.BeginInvoke() .. etc), but wasn't able to solve my problem.
I have some shared code I need to use both in a WinForm and a service. How can I test if my code is running in a service, so I can avoid problems with modal dialogs.
View 2 RepliesI have build a VB.Net windows application which does uploads data into database and basically updates two controls:
1. A textbox which is constantly updated with one line per database record upload.
2. A label which keeps track of the count of database record uploaded.
I have used BackgroundWorker thread concept, where the thread's bgwWorker_DoWork() method contains the business logic for upload and bgwWorker_ ProgressChanged() updates the 2 UI controls based on uploads.But the issue I am facing is that I do not get complete updates on both the UI controls. Sometimes the thread bypasses update of textbox and sometimes of label. I could resolve this issue by adding System.Threading.Thread.Sleep(25) before each UI control update code.[code]
could someone tell me how to fire an event in main thread from another thread as well as fire and forget without use a new thread?
View 9 RepliesI'm developing a WinForms app in VB.NET, that handles sets of style data, and when the user clicks on another set's label, it prompts through a dialog "You are leaving this style preset to edit another one. keep changes on this one? [Yes] [No]".But, I'm facing the problem that, when the user clicks either option, and the dialog closes, everything has to be refreshed, and loading the form again seems a good option.[code]But as soon as that sub is called from the prompt, it crashes the application. (doesn't show an error in debug, simply crashes) How should I, from a given dialog, close the dialog, it's parent, and re-open it's parent? (which triggers all the Dialog_Load() code of the parent)
View 2 RepliesIn form I have one button which has functionality to pick up some data from (by mouse click) Parent application.
I have handle for parent application handle, but even if i tried to bring it on top i am not able to do selection because form is modal.
Requirement here is open modeless dialog and wait till it close. other wise it goes further and executes functionality below.
Another option can be open form as modal and at runtime change it to modaless.
How would i go about closing my openfiledialog in the event that there is an error[code]...
View 12 RepliesI am using VB.Net 2010. I have two dialog forms open at once. the form that does not have focus I am trying to close and reopen to show the value changes. Below is what I have.
[code]...
the form associated with f never closes, however does open with the new values. I have tried Application.DoEvents and that hasn't worked.
I've built a dialogbox with a RichTextBox and I'd like to have the following behaviour:
I've got the focus (cursor) in the RichTextBox. When the ENTER key is pressed, then there should be a new line in the rich edit control created. The ENTER should NOT close the dialog box [as it does now :-( ].
Whenever I try, the save file dialog comes up when I hit No and same when I hit Cancel....
If My.Settings.SaveSTS = False Then
MsgBox("Do you wish to save your changes?", MsgBoxStyle.YesNoCancel)
If MsgBoxResult.Yes Then
If My.Settings.OnceSaved = True Then
Dim writer As New IO.StreamWriter(SaveName)
[Code] .....
When the checked state of a check box change, I would like to know what the new value is.his is what I am doing:Friend WithEvents clstTask As System.Windows.Forms.CheckedListBox
Private Sub clstTask_ItemCheck(ByVal sender As System.Object, ByVal e As System.Windows.Forms.ItemCheckEventArgs) Handles clstTask.ItemCheck
Dim SelectedCheckState As CheckState = clstTask.GetItemCheckState(clstTask.SelectedIndex)
[code].....
When I am inside a thread, I cannot simply call Me.Close or I get cross threading error!So I need to use some code like this and then call SetClose()
[code]...
A Dialog that is added to a Windows Forms project comes with two buttons (OK and Cancel) and Click event subroutines for each. The subroutines close the Dialog with different DialogResult enumerations. Here's the code in the one for Cancel: Me.DialogResult = System.Windows.Forms.DialogResult.Cancel Me.Close() But either statement (changing DialogResult to an enumeration other than Null or Close), by itself, will close the Dialog as well. (Try commenting out one and then the other to prove it to yourself.) Here's the question: Why both? Why not just one or the other?
View 1 RepliesI have made a little programme where the user can put in a name to search for a contact.The matches then fill a Datagrid and the user can then choose the one they want and the programm then opens the contact form (from outlook client)The Contact form opens ok, and it brings up the correct contact. If the user then selects the option to "Email" from that from I then get the error message"A Dialog is open" etc...
My code is as follows
Sub GetContact()
Dim objOutlook As Outlook.Application
Dim objNS As Outlook.NameSpace
[code]....
It seems to be due to Outlook being open or opening?
i am having a thread to keep the application in sleep for some time after the application process a data.
[Code]....
Currently, the application gets hanged if i press close button when thread.sleep() is running. How can i make the close button to close the application even when the thread.sleep is running.
I am trying to give some user entertainment, and show a "please wait" window, with Marquee, during the loading of a separate complex Window. I am attempting to do this by loading the Window in a new thread, like this:
Public Function ShowPleaseWait() As System.Threading.Thread
Dim PleaseWait As New System.Threading.Thread(AddressOf LoadPleaseWait)
PleaseWait.SetApartmentState(System.Threading.ApartmentState.STA)
[code]....
In the calling code, it calls ShowPleaseWait and saves the Thread for later.. To close the window, it calls Thread.Abort, on the saved thread. This in turn will causes it to enter the Catch. I have tried, many different ways, with and without the catch.This works incredibly, the first time it is called. However, additional calls will fail at window.Show() with the exception: The calling thread cannot access this object because a different thread owns it..This really puzzles me as the window was created one line above the call to window.Show and is local. How is it owned by a different thread? How can I fix this?
How can I close or stop a thread. For example
Dim trlisten As Thread
Is it trlisten.Stop? or trlisten.Close? or what?
We have a winform application using Oracle DataAccessClient.There is a gridview and textboxes where we when we click on a row we can populate the textboxes to show more of the data so the user does not have to scroll horizontally.The code that does this is in the cell click event. We want to also do this if the user presses the up or down arrow. We put the code in the PreviewKeyDown event but we are getting the row that had the focus rather than the row that has the current arrow pointing to it. We searched the web at a lot of forums but we can not seem to locate how to do it. How do we move the focus to the row the arrow is pointing to in the grid? [code]
View 2 Repliesi have a databound datagrid in vb.net 2008. This is a program where i use the double click event multipal times.. but for some reason on a new form it's not working anymore. In code behind i selected the datagrid and double click event. when i double click on teh grid in debug mode, it never fires off the event(i put a breakpoint in). I've tried several other events and none of them are firing.
View 1 RepliesI'm trying to capture the initial value of a listbox immediately after it's clicked on, and before the SelectedIndex is changed. The following was taken from: MouseDown in WinForm ListBox Kills SelectedIndexChanged, converted to VB. The ListBoxComponent Class is in a Component that shows at the top of the Toolbox.
Public Class ListBoxComponent
Inherits ListBox
Public Const WM_LBUTTONDOWN As Integer = &H201
Public Event PreSelect As EventHandler
[code]....
when I try to perform a cross thread call to fill a text box with messages with the following code I have no problems:
Delegate Sub SetTextCallback(ByVal [text] As String)
Public Sub SetStatusBox(ByVal [text] As String)
If Me.statusBox.InvokeRequired Then
[code]....
However, I am having problems when I use the following code to do a cross thread call to close a form. The form just hangs there.
Public Delegate Sub setFormClosing(ByVal ctrl As Control)
Private Sub closeForm(ByVal ctrl As Control)
If Me.InvokeRequired Then
[code]....
I have a userControl11 (either in winform or wpf) which has a ValueChanged custom event. If I put it in client form and in form_load set its value to 100, it will trigger the ValueChanged event. But if I set this value inside the constructor of UserControl1 the custom event won't trigger. How can I force it to do so ?whatever the technical reason, functionally it does make sense. If the object is initializing its value from some sources unknown to the client form and the client form has a textbox bound to this usercontrol value, it is sure convenient that it could refresh its textbox at any time including when the form loads just using one single event handler. Without this the client form has to create another initializer for this bound textbox at form load.
Below the source code of my trials in winform:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
[code]....
I am trying to create a background worker that will spawn a dialog, while a long event is occurring. For example, when the main thread in trying to connect connect to a db and update a large amount of records, I would like to have the background worker spawn a dialog that advises the user to "Please Wait"
Here is what I have so far
1. I create a background worker using the drag and drop
2. Before the event that taking a long time starts I call:
Me.BackgroundWorker1.RunWorkerAsync()
BackgroundWorker1.WorkerReportsProgress = True
3. This is the events for the bgworker, all of which was enabled in the form designer:
Private Delegate Sub delCreateNewForm()
Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
Dim d As New delCreateNewForm(AddressOf CreateNewForm)
Me.Invoke(d)
[Code] .....
4. When the long activity is completed I call this:
BackgroundWorker1.ReportProgress(0)
Everything seems to work fine, except that the newly spawned dialog in no responsive and appears to be frozen, until its closed by the Progress Changed event.
I tried raise an event from another thread, but various error about classes and so on. I try to avoid classes.
Error 1 Cannot refer to an instance member of a class from within a shared method or shared member initializer without an explicit instance of the class. C:Documents and SettingsLMMy DocumentsVisual Studio 2008Projectssarja4bWindowsApplication2formsForm1_saielyhyt.vb 179 32 sarja4b
I am using VB2008
I used threads because I wanted to test and play with them. Threads worked I think, but now I wonder what is wrong with events?
SerialPort1.DataReceived seems to suit better here, but why don't my events work?
Here is skeleton of my code
Imports System
Imports System.IO.Ports
Imports System.Threading
[Code]....
I'd like to create a WebBrowser for the purpose of taking a screenshot of a website. Once its finished it will update a thumbnail image in a ListView. I'd like the whole operation to be done in the background so the UI remains responsive.I toyed with Creating the WebBrowser in a new thread and calling Navigate. I can use a loop to watch for the ReadyState of the webbrowser before I do the screencapture. However it will only continue with the thread if I use Application.DoEvents in that loop. I've never been a huge fan of doing this and would prefer to watch for an event instead. However if I add a handles clause to the WebBrowser it doesn't fire (I tried creating the WebBrowser in the thread, and also tried by declaring it as shared within the class scope).
View 3 RepliesI have a VB.NET application writtene using VS 2008 and have been receiving a weird error when a form is closed - it gives me the following error message:
Windows has triggered a breakpoint in MyApplication.exe.
This may be due to a corruption of the heap, which indicates a bug in MyApplication.exe or any of the DLLs it has loaded. This may also be due to the user pressing F12 while MyApplication.exe has focus. The output window may have more diagnostic information.
The immediate window then has this error message:
Critical error detected c0000374
I tried fixing this by just hiding the window, but this simply moves the error up the chain and I get an error when exiting the program as it tries to close the form:
Unhandled exception at 0x7700e29b in MyApplication.exe: 0xC0000005: Access violation writing location 0x00000000.
I don't think I'm doing anything particularly strange in my application - reading from and writing to a database is about as complicated as anything gets for me. I've tried using AppVerifier, but then the program won't even open. I'm at a real loss as I don't know anything about memory management, or what a heap is. I just can't work out why this error is happening
By the way, the application compiles and runs fine on my old 32-bit computer running WinXP professional, but my new 64-bit Windows 7 computer is just not having it, even though I have targeted the compile for x86 and followed every bit of advice I could find on geting it to work in Windows 7. Should Windows 7 and VS 2008 really be incompatible? Do I need to get VS 2010 instead?
I want to execute some code in the MDI Parent Form when an MDI Child Form has been closed. What Parent Form Event would be best.
View 6 Replies