Try / Catch Not Trapping Exceptions
Mar 25, 2011
I am working on an app that uses a third-party charting component.It is a .Net component. There have been some occasions when exceptions have occurred inside the third-party component code, but my try/catch is not trapping them.Should they get trapped?My code is structured roughly like this:[code]I have since found and fixed what was causing the exceptions, but I would have thought that this should trap them. What happens when I run in the IDE is that it crashes and Visual Studio throws up a page telling me there is no code available to debug, and no disassembly available.Fair enough, but I repeat - why doesn't the exception get trapped?
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Dec 22, 2009
In my code I'm using the Try-Catch functionality. All errors are written to the event viewer.I do it now with identifying the lines of code with a number.
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Jan 23, 2012
I need to catch log4net exceptions (its own exceptions not app exceptions logged by it). I wish there's a way of doing it this way: [code] I have this code implemented and there's no errors in compilation but i force log4net to have an error (pointing to a non existing database in the config file) and nothing is threw.I've tried the listener aproach: [code] and it's writing the errors to log4net.txt, the forced ones i mean.This last aproach has a couple of drawbacks: it won't append every error to the file, if the error is the same it doesn't write it, i can't get the listener to write every error to that file, only one (I don't know how to fully configure the trace listener, it might be that). Thus it won't append the date and hour to every line wich is a necesity for me. Finally i can't give structure to it (xml). Even if the listener work i need to use the try/catch aproach, since i'm using ExceptionHandling from Enterprise library to log the errors in my app.
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Jun 10, 2009
When you use Try Catch for Exceptions, will
Catch ex As Exception
Catch any possible error that could occur or do you have to catch each exception separately?
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Feb 4, 2011
Is there a way to catch these Exceptions? (I am not looking for "just put try/catch or on error goto around them"). I am trying to find out if these errors can be caught by something outside of them.[code]...
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Aug 17, 2010
Is there a way to catch all SQL exceptions in a project? I have several gridviews and multiple sqldatasources and most of the errors are going to occur when a user enters something incorrectly or in the wrong column. So how do I stop the Server Error in /Project page from showing up?
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Oct 13, 2010
Is there some special way to catch exceptions in finally block ?
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Jan 5, 2012
Is there anything similar to the MyApplication_UnhandledException for an user control in VB?
I would like to have a central point where to catch all unhandled exceptions of a user control, without propagating the exception to the application that uses the user control. I made some test raising an exception in a method of my user control where there is no try/catch code (of course in the true project all methods have a try/catch block). The exception was caught by MyApplication_UnhandledException event of the application using the user control. But this is too "far" from the point where the exception happens and in worst case the user should restart the application.
I would like to realize a behaviour for the user control in order that if the user control fails, the exception is not propagated till the application, but just caught at user control level.
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Apr 8, 2011
I have a SqlDataReader and I want to trap any exceptions with Try Catch Finally if the reader =cmd.ExecuteReader() statement fails. If this statement throws an exception do I need to close the reader? If so, where. Wherever I place the reader.close() statement I get an error that the reader has not been assigned a value yet.
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Apr 20, 2010
A few weeks back in reply to a thread, I said then that it's sometimes worse to use a Try/Catch when there's nothing in the Catch!There are exceptions to that I'm sure, but too often the Try/Catch is used with a blank Catch that makes even the developer scratch their heads when the program crashes because they have nothing to go on (by their own doing).DevExpress (and I'm a big fan of their stuff) has a little three minute video that encapsulates that concept well and I thought that you all might enjoy watching it:[URL]
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Apr 6, 2011
[Code]...
Notice the catch (Type) instead of catch (Type myVariable). Is this possible with VB.NET, or do you always have to declare a variable when you catch exception types, like so:
[Code]...
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Jan 25, 2010
so i have a Method that is going to made Thread Safe. can i have something like this in the Method:
Public Class Q Private Shared ASD As New MyException("") Public Sub W Throw ASD if multiple threads attempt to throw the Shared exception ASD, will there be an error in the catching part? The alternative of course is to: Throw New ASD but i'm just checking to see if the first way is thread safe
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Apr 2, 2011
I have an assembly containing a number of classes. This is a class library type assembly, not a windows forms application. It's also single threaded.Is there a way to catch all un-handled exceptions so that I can log them?
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Jan 31, 2012
I wonder how to use statement handles exceptions?Do I need to wrap the using statements with a Try/Cath/Finally clause in order to be sure that the SqlConnection object is closed and disposed even if the containing code throws an exception? [code]
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Oct 19, 2011
I would like to catch any exceptions from any method in a class so that I may record class specific data to the exception for logging before it is passed up the stack. I know that I can put a try-catch in every method of the class, but there are many methods and It seems there should be a more efficient way. Example of what I am currently doing:
public class ClassA
{
private int x;
[code].....
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Oct 5, 2009
how to use them then before, but am still a little confused with a few aspects. Here goes:
1.) Lets say you have a method that checks for a certain condition(s) and if it fails Throws an exception. Does it have to be in a try/catch block? Meaning can the "Throw" statement exist in a block with no try/catch statement?
2.) Now lets say we have a method that has a try catch block and in it there is a throw statement. When the throw statement is executed does it first try to find an appropriate catch block in the same method or does it immediately go back to the calling method without looking at the catch statements in the current method where the exception was thrown?
3.) I created a custom exception class that inherits from ApplicationException. Next I created a method which has a catch block that catches this type of exception and does some action. Is the System(i.e CLR) smart enough to throw an exception of this type, or does it only throw exceptions from SystemException?
4.) I know that some people are more liberal in their use of exceptions and others use it more sparingly when truly strange stuff happen like the DB going down. I am writing code where I am getting some info back from the database, converting it and then storing it. Sometimes there might be data that comes back from the database and other times the field is empty and the Null value comes back. Therefore in the instances where Null comes back from the database I should not convert the value to anything, since I will get an error. What should I do in this situation? Should I let the CLR throw the exception when it goes to convert the Null value or should I check for the Null value and if it exists not convert?
5.) In general when I throw exceptions, is it sensible to only throw exceptions of the type Application Exception or are there instances where the programmer throws exceptions of the type SystemException?
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Dec 26, 2009
I've just skipped around a few inbuilt VB classes' methods which throws exception. of all that i've came across, methods may throw multiple exceptions but ALL of them are exclusive, meaning there is no way 2 exceptions will ever occur simultaneously, yea and i was trying to make my class throw 2 exceptions simultaneously, hence this question, must all exceptions be exclusive?
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Mar 25, 2011
I have a program in VB.Net that receives mails from Outlook, extracts attachments and inserts the attachments into a table through a query. I would like to put the query/queries in a Try/Catch block, but cannot do so as Outlook exceptions cannot be caught, and it gives me an error, and unless I put a very specific exception, I cannot catch it. Is there a workaround?
Edit:
Try
Catch ex As Exception
End Try
Exception is underlined and when I hover on it, it says: "Catch cannot catch type 'Microsoft.Office.Interop.Outlook.Exception' because it is not in 'System.Exception' or a class that inherits from 'System.Exception'". This is affecting all my other code which I'd like to put into a Try/Catch block.
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Jun 19, 2012
The following code causes a "Warning" that Variable is used before value assigned.How do I restructure this Try/catch to eliminate error on the myreader.close command in the Catch part? Code appears to work fine but I dont like Warnings. [code]
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Apr 1, 2011
i have problem when i click a ADD button, there is one null value in the textbox .. so the try catch statemnt is to catch that null value error but after that the catch is success but the button click never stop excute the statemnt till the end of the button event.
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Mar 4, 2009
I have this scenario: in a Sub I have a Try...Catch statement.Within that Try..Catch I call another sub.In that 2nd sub is also a Try...Catch.(see below for example).Now if an exception occurs in the 2nd sub's Try...Catch, which Catch gets excecuted? The 2nd one, the 1st one or both?
Private Sub sub1()
Try
..do stuff[code].....
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Jun 27, 2012
A user will enter a name and a text score of a student. The names and scores are saved in a list box and once they are stored I click 'show the array' and I get a parallel array filled with the names and scores.
I need to error trap the text box's so that when the user inputs a number its a number between 0 and 100. IF its not it needs to end the button click event.[code]...
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Oct 7, 2009
What I want is a Global Error Trap that will not stop code execution. What I have found is examples where each module requires some code or a Try block. I need it to be totally generic. Everything from UnHandledExceptions to conversion errors.
If I have to use try blocks all over the place then it is not Global Error Trapping.
I need code at the highest level possible that will always catch any and all errors reported by VB.[code]...
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Apr 22, 2011
I have an app in vb net 2005 which has code similar to' start external thread ShowRandom Images.start Open database & do other preliminary setup 'abort thread ShowRandom Images. abort 99 times out of 100 I never get a problem, but if system appears to be slow or other heavy processing, I get "Thread being aborted"..How can I trap or ensure the error message does not get to my users
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Jun 2, 2009
If I throw an exception from within a catch, does the finally (from the catch) still execute? i.e.
Try
..some code with an exception in it...
catch ex as Exception
throw new SpecialException("blah blah" & ex.Message, ex)
[code]....
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Dec 6, 2011
i am creating an activeX control... in this control i want to manage what the tab key does. i may a user interface that allows tabs in the textbox or it might move the user to the next screen. i have everything working in the IDE, but when my activeX is loaded into the 3rd party application the tabs no longer trigger the key down event. i assume this is because the parent application has tab stops is there a way on a control by control basis to stop the normal execution of tabs?
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Mar 19, 2010
I am having problems clicking a link on a page.I was thinking of trapping the click events in the web browser when I manually click the link to see if it uses any other post variables from that page or what happens when I click the link.
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Jul 29, 2009
For a NumericUpDown control in VB 2005, how do I distinguish between a change to the numeric value made by the user (by changing the text or clicking the up or down arrows), and a change made internally by my code? The "Scroll" event works for user changes to the TrackBar control, but not for me on the UpDown control, and the ValueChanged event doesn't distinguish the source of the change.
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Oct 20, 2010
Is there anything I have to do to trap wheel mouse events?I have a panel and can trap the MyPanel_MouseMove events but not the MyPanel_MouseWheel events.In VB6 you needed to add wheel hook & unhook commands - do I have to do anything for VB2008?
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Jun 8, 2009
Try
If Me.CompanyNameTextBox.Text.Length = 0 Then
MessageBox.Show(
[Code]....
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