Catching Error In BackgroundWorker?
Dec 22, 2009
I am using BackgroundWorker to connect asynchronously to a database. Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
[Code]...
While my connection is being opened, I have a "Loading" animation show in a lblCalibration. Once it's connected, the animation stops successfully and shows the calibrated record that I am fetching from my db.
However, if there is an error while connecting to my db for any reason, it does not work. My app freezes. The reason is because I am trying to make a cross-thread call while trying to Catch the error in the DoWork event.[URL]..
but still cannot seem to make any progress. Does anyone have any tips or advice on how to properly catch the error and still run BackgroundWorker?
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Dec 14, 2009
in my button click event i ececure
If BackgroundWorker4.IsBusy Then
BackgroundWorker1.CancelAsync()
End If[code]....
after proceess completed if press the button again.i got the following error msg
This BackgroundWorker is currently busy and cannot run multiple tasks concurrently.
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May 8, 2009
I have 5 errors that come up every time I run my project They are all "A first chance exception of type 'System.ArgumentException' occurred in System.Drawing.dll"
I have try catch blocks around every piece of code I have written, and it does not seem to catch them, so I opted to catch the appdomain.UnHandledException.
That does not seem to catch them either If I step through the code line by line (several hundred lines so I hold down f8) it does not make the error...
Only when I run full speed.
I can only figure that I am accessing something maybe before an object is completely drawn, however how in the heck would anyone suggest I go about finding it, and why will my global event handler not catch them?
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Apr 13, 2011
I run a program multiplying decimals with integers. If a user enters a non 0 number etc. the try catch works its charm. i added some lines to clear the text boxes and that works fine but
lblReva.text = ""
does not clear the labels where the answers are displayed, on the contrary it displays the correct value calculated and enters a 0 for the erroneous entry. I would like to clear all the labels and text boxes(except the instruction and assingment labels)so the form is clean once more so the user can try to be "more on" target next time.
Try
decReva = CDec(txtBoxa.Text)
decRevb = CDec(txtBoxb.Text)
[code]....
Not integers but constants declared as decimals but that is immaterial here. "Doh"
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Mar 7, 2009
I'm trying to improve my app with some error catching. I have a module that downloads a file from the Internet to a local folder. At the moment, if the local folder doesn't exist, it just crashes here:
strLocalFile = New FileStream(pPath, FileMode.Create, FileAccess.Write, FileShare.None)
with error:
System.IO.DirectoryNotFoundException was unhandled
Message="Could not find a part of the path 'C:Documents and SettingsSimonDesktop estdownload.zip'."
Source="mscorlib"
How can I do something with that error and stop my app from crashing? Ideally, have a messagebox show saying 'directory not found' or similar.
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Nov 4, 2009
I'm editing some settings in the registry and then adding items to a ListView.
[Code]...
If I'm not mistaken, the code will not continue in the Try block if the first part fails and then move on to the catch statement, correct? I'm adding and deleting a bunch of different entries in the registry and the computers I've tried my app on so far, have not failed. So I'm not able to test if this method will work for error catching. If there's a better method, I'd appreciate the info.
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Dec 11, 2009
I have used the code from the link below to create a basic login page in front of the Microsoft Live Single Sing On.[url] I managed to combine the two together(LiveSSO w/Forms Authentication) turning off the Integrated Authentication in IIS from the SSO setup.All works as expected if the user successfully authenticates with AD. THE PROBLEM that I am having is that when the user failes to authenticate it only returns: "Error authenticating user. Logon failure: unknown user name or bad password". This message appears also when the user is set to change the password at next logon. What I want it to do is to read the error code of exactly why it failed so I can setup a redirect to a password reset page (i.e. if error is "User flag is set to change pswd" etc.etc.)From the page linked above you can see the VB code of LdapAuthentication.vb which does the trick of authenticating the accounts or returning the error message if the login fails. The part that returns the "Error authenticating user. Logon failure: unknown user name or bad password." Is handled by this subroutine:
[code]...
That's what I have been trying to customize to see how it can return a specific code based on the user account AD flags, instead of the generic message
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Mar 22, 2010
I know it is possible to run a vbscript from within VB.NET (Visual Studio 2005 / 2008) s it possible for VB.NET to catch the vbscript's exit code? I know it is possible within a HTA:
[Code]...
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Dec 30, 2009
[URL] using this method results in a modal dialogue box which the user must manually close by pressing end or debug or the VBA (and consequently the VB) code will hang.I am unsure how to get the message box to close.
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Nov 4, 2010
I've been whining for several months about the way Windows 7 prevents application exceptions from actually occurring, and arbitrarily assigns "compatibility settings" without actually detailing what those settings are, even during Visual Studio Debugging operations. Am I just completely ignorant to some setting I can toggle to turn all that garbage off and make Win7 act like an operating system that wasn't designed for a 2 year old? It never hurts to try. In a worst case scenario,
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Sep 27, 2011
I have a search function in my program that uses a background worker in order to get the results. The Progress changed event is used to update the listview with the new item.[code]
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Feb 16, 2010
I cannot figure this one out.. I have a background worker that will perform a task streaming data from some webpages. this data is then passed back and displayed in a gridview. It has been working fine.
I've recently implemented a listbox, which its values will be passed into the function that the background worker will perform as parameters, originally i had taken a single value from a textbox.
Now, I thought maybe it had something to do with the listbox, so I used a static value, just a simple String, as the parameter, and again, I get the TargetInvocationException was unhandled.. There's no difference in how I perform the task I'm trying to have the backgroundworker complete, the only difference is where it exists in my if condition statement:
Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles ScrapeSites.DoWork
Dim results As ArrayList
Dim worker As System.ComponentModel.BackgroundWorker = DirectCast(sender, System.ComponentModel.BackgroundWorker)
[Code]...
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Feb 21, 2012
I have a project in VSTO/VB using a BackgroundWorker that works fine. It is a form that calls for a web page of information. The web page can take a while, so I have the form calling with the BackgroundWorker.I then have an Excel Addin project that has added the BackgroundWorker project. When I call up the form from the Excel Addin project and use the BackgroundWorker to request the web page, it grabs the web page ok. But the work done upon completion, during the BackgroundWorker1_RunWorkerCompleted method, is resulting in an error message:
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Aug 8, 2009
[Code] This is run from inside a backgroundworker. It throws an error, Cross-thread operation not valid: Control 'pbUpload' accessed from a thread other than the thread it was created on. I have read and read and searched and basically come to the conclusion I am going to have to invoke the command but this is new area for me.
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Jul 20, 2010
I am using a background worker's work method to create a new form and show it.
But it throws this error
System.Threading.ThreadStateException was unhandled by user code
Message="Current thread must be set to single thread apartment (STA) mode before OLE calls can be made. Ensure that your Main function has STAThreadAttribute marked on it."
[Code]....
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Jul 5, 2011
I have a backgroundworker that is downloading data from different webpages and process them to a datagridview.I get the Cross-thread operation not valid error on the first For loop.
Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
dim i as integer
tot = (numPostnrTo.Value - numPostnrFrom.Value) / 10
[code]....
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Oct 6, 2010
Let's say a custom exception is thrown in the DoWork event for a backgroundworker. How do I pass the custom exception to the backgroundworker so that it ends up being the e.Error in the RunWorkedCompletedEventArgs?
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Apr 2, 2012
i'm in the need to start a backgroundworker inside another one.Now...The first one BGW starts a for cycle, and inside this one there is the second BGW that has to upload an image to a server.The trouble is that, the progress event and the complete event of the internal BGW are never called.
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Mar 14, 2011
I am trying to catch an exception but occasionally get an inner exception. I want to output both into a label. I often get Object reference not set to instance of an object if there is no inner exception.
Catch ex As Exception
exError = ex.Message.ToString
If Not ex.InnerException.Message Is Nothing Then
[Code]....
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Apr 5, 2011
When I debug a program my IDE simply does not catch System.NullReferenceException - execution continues as if there were nothing wrong.Moreover, when I go to the menu Debug/Exceptions System.NullReferenceException is not even in the list(Common Language Runtime Exceptions).
I manually add it (there is the Add button) and I put a checkmark in the 'Thrown' and 'User unhandled' column - now IDE catches it, but after I re-load the project the situation re-appears - and NullReferenceException is not on the list again. What may be wrong?
Update:No, when I step through the code the execution does not continue but exits the current block of code (sub or function). There were no Try...Catch blocks and there is a message: A System.NullReferenceException occured in MSCorlib.dll... But why doesn't the debugger stop at this line?
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Aug 8, 2011
I have a simple function which tries to get a value from an Obout grid filter column, and if the value is empty, ignores it and moves on. For some reason this code ignore my catch block and always shows a System.FormatException when the input string is empty More bizarre, if I use visual studio's debugger and set a breakpoint on that line, the catch block functions normally (after I continue from that line). I have already confirmed that my Debug | Exceptions | CLR are not set to catch when thrown. I have also confirmed this same behavior in the production version.
[Code]...
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Feb 24, 2012
Take the TripPriceService.wsdl from this link Add a service reference(ServiceReference1) to a windows application, by giving the wsdl from the mentioned wsdl file saved in local folder. My question has two parts
1) Is the below fault message a valid soap fault as per the wsdl(TripPriceServiceException)?
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:trip="http://trip.price.service">
<soapenv:Header/>
<soapenv:Body>
[code]....
2)Now How to handle and catch the detail tag, when the response is a soap:fault?
Imports windowsapp1.ServiceReference1
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim obj As New ServiceReference1.TripPriceServiceFacadeClient
[code]....
The line obj.getTripPrice, invokes the service. However will it throw an exception if the response is a soap fault(of type TripPriceServiceException)? How to handle such cases, do we need to use ServiceReference1.TripPriceServiceException? We are in a need to handle such faults in our webservice client.
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Feb 18, 2012
Private _pages As New List(Of Panel)
Public ReadOnly Property pages() As List(Of Panel)
Get
[code].....
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Apr 5, 2011
I have read the documentation on RaiseEvent and Even but still confused. I am using a class that i call that performs a task on a thread.
vb
Public Property MyVar As String
Public Sub MuSub()
[code]....
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Sep 16, 2009
'SHEETS For Each ctrl As Control In Me.Controls What am I doing wrong here? When I put in manual text after the line return it fill in but as is it doesn't pick up all the checkboxes under HEADINGS. It does create all the sheets under SHEETS.
Code:
If (TypeOf ctrl Is CheckBox AndAlso CType(ctrl, CheckBox).Checked) AndAlso CType(ctrl, CheckBox).Name.Contains("Sheet") Then
wb.Worksheets("Template").copy(after:=sheet)
[Code]....
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Apr 1, 2010
I'm not even sure if that's what I want.But, here's my question. I have written a small program to automate the running of some files. These files have the potential to give an error in the form of a MessageBox which will halt the whole process. Is there a way to detect if that window pops up so that I can kill the process so the next file can run.
Also, if I can get the location of this MessageBox, is it possible to get text out of it so that maybe I can email myself the error so that the processes can keep running but I cango to that file and fix it.
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Apr 25, 2012
I put a try/catch block around a bit of code that occasionaly throws an expected exception, but rather than catching it and displaying the message box, it stops the debugger and alerts me that the exception is unhandled.How do I handle this exception so my code doesn't stop when the exception occurs?
Friend myDevInfo As New devInfo
''' <summary>
''' Closes the device handle obtained with CreateFile and frees resources.
[code]....
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Feb 5, 2011
I have a VB.NET application (VS2010, .NET 4.0) that seems to throw an exception under some unknown conditions after a number of hours. In addition to the main thread, there are additional threads running. In reading this link: [URL] it seems like this would be a big help in trapping this exception. I have what are probably some very basic questions:
1. I assume ErrorHandlerForm() in the example refers to the main form of the application, setup.vb in my case. Therefore the last line in the example should be:
[Code]...
I would have expected to to replace ErrorHandlerForm.Form1_UIThreadException with find a setup event such as Setup_UIThreadException but there doesn't appear to be sucn an event.
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May 5, 2011
While I understand ApplicationEvents.vb won't catch exceptions in another thread, is there any reason why it shouldn't catch exceptions in the UI thread? From time to time I get exceptions that simply crash the program, even though an exception handler is defined as follows:
Private Sub MyApplication_UnhandledException(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.ApplicationServices.UnhandledExceptionEventArgs) Handles Me.UnhandledException
[code].....
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Jun 30, 2011
I have a simple form with one text box that pass data to SQL and I want it to submit when the user hits the enter key.
In Firefox, this works great. The user puts a number hits enter gets back the results.
However in IE 8 and IE 9 this is not working.
<form id="form1" runat="server" accept="cmdclick"
style="background-position: center; background-image: url('BG.gif'); background-repeat: no-repeat;">
[Code]....
I am not sure what would cause this. I see a lot of people using JavaScript to go around the problem however I do not know how to write JavaScript code.
How can this be done (preferably without JavaScript)?
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