When debugging a program, instead of doing this on EVERY piece of code:
Try
MyFunction()
Catch ex as Exception
MsgBox(ex.Message)
End Try
Is there a way to apply that to everything error I encounter without writing it on every function/sub/etc?
All of us use the try catch blocks. But what is the best way of handling errors within custom functions?Display a messagebox to the user when the exception is thrown (if possible within the function), or return a value indicating that an error was found within the function?
View 3 RepliesI have a custom control I'm creating. When I click on it, it draws a dotted border and puts some nubs on it for resizing. This all works perfectly. Now I want it so when I click off of it, it deselects. I already have a variable to set up if it's selected or not and subs to draw/clear it. I just have to be able to detect when something else is selected or it gets clicked off of.
What I've Tried
My first and best solution to this was to use the LostFocus event, but, by custom control apparently won't let it fire. After some research, as far as I know, custom controls don't have Focus events because they are custom and could be changed (basically, you have to implement the focus events yourself).
My Question
Does anybody have a solution to either implement the focus events or a way to handle off clicking for custom controls?
Sources
Here is my controls current source:
Imports System.Drawing.Drawing2D
Public Class wDOMElement
Inherits Control
[Code]....
I have a custom class which basically manages the program settings.
In it's New() event, I'm performing a check to see whether a value stored in My.Settings is the same as the default value (I made sure the value wasn't!), if not then it will perform a RaiseEvent ValueChanged().
On my form, I have an instance of the class declared "Private Withevents ProgramSettings as New clsProgramSettings", I also have a handler "Private Sub DoSomething() Handles ProgramSettings.ValueChanged" declared.
When I run the program the form gets loaded, the instance is created, the RaiseEvent is called, but the handler is not receiving the event?
I tried "Private Withevents ProgramSettings as clsProgramSettings", then creating the instance in the Form.Load(), but still no success!?
Is there something I'm doing wrong, or is there a problem with the IDE? I'm using VS 2010.
So I've made this control that inherits from the treeview control and basically loads objects from active directory into a treeview (url...).All working fine, but as this is the first custom control I have made that I have intended for other people to use, I'm not quite sure how I should approach error handling.I mean, obviously I shouldnt do something like show any exceptions in a messagebox because that might not be what the person that is using the control wants to happen. So do I just write out exception messages to the debug window? Do I swallow exceptions (guessing not)? Do I just totally ignore them so that they are thrown in the user's project?
View 4 RepliesMy application's binary serialization was working well up to today (this is not a released app yet - still in development). I have a "Project" class that is the top-level class of a hierarchy of other classes related to its function. And before you think it, yes, all of those classes are marked as serializable. Infact, they all were being serialized before today.
I have one event on the Project class that assists in informing when the project's save status has changed (i.e. new, modified, saved). This event was added today along with some events on the other classes that filter up to the Project class (the project needs to be told when its objects have been modified). I unfortunately added all of this at the same time so I can't provide any incremental details as to when it stopped working, but when I try to save the project through my binary formatter it tells me that my main form is not marked as serializable. Well, yeah... of course it isn't! it shouldn't need to be because there is no member of my classes that even mentions the form. But for some reason handling the Project's event on the form triggers this error.
Serializing the form is not a solution. Neither is not being able to handle my Project events. If I comment out the handler it works fine -- and I don't even have to remove the WithEvents keyword on my form's Project variable. Now that I write that I'm speculating that it may have to do with the event being raised as a result of the serialization (occurs when the save button is clicked).
I have an object, say Order where if an error occurs, it raises the ErrorOccurred event. If I'm running some code in say, the codebehind for a .aspx page with an public Order registered as WithEvents and I want to check to see if an error has occurred before I run more code, how do I do this? I can't simply check theOrder.ErrorOccurred. Do I have to create a local boolean flag that switches over in the event handler (OnErrorOccurred)?
Example:
Public WithEvents theOrder As New Order
Public Sub DoStuff()
theOrder.DoSomething()
If theOrder.ErrorOccurred Then
[code]....
Here's my Application_OnError event sink in global.asax.vb:
Sub Application_OnError(ByVal sender As Object, ByVal e As EventArgs)
Dim innerMostException As Exception = getInnerMostException(Me.Context.Error)
[code].....
What error handling should be used in VB.NET? Should one use the "On Error Goto ErrorHandler Exit Sub ErrHandler ... End Sub" pattern or should you use the "try {... } catch {...} finally {... }" pattern?
View 4 RepliesIn my vb.net application if I have a known set of Error Strings i.e.
Failed because I don't know about it
Failed because I know about it but I can't find it
Failed for another reason
[code].....
I am just doing a bit of error handling. I am just check to make sure that a user has selected an option within a combo box (named cbtitle1) and if option has not been selected throw an error message to tell the user.this if statement is within a save button which once a user click save this error checking runs first then if combo box has an option selected the save goes ahead else it throws an error.I can stop the save function OK but I wanted to put a error icon in with the message box but I get an error when I add it.[code]
View 3 RepliesObviously error handling is a major factor in making a good application. If a error happens letting a user know what has gone wrong.But some times error handling may(i think) not be needed. Example.
Private Sub RemoveCheckedl()
Try
For Each Item As ListViewItem In lst.CheckedItems[code]....
also when error handling it's could to think about what type of errors could be made.
Catch ex As Exception
MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
even though this catches the error and displays a msg, it may not be a great message for the user so he/she can understand.
I am working on an executable to load set of data into databases.I will be running it as a windows service. I will be doing several different checks to see if the fields exists in the incoming files. When i do the checks using if statements.I would like to stop processing when a major error occurs or when any thing is interrupted Like say windows crashed. I would like to create an error file with the error message in it for that particular file. I would be monitoring error folder everyday to check if there are any errors.
View 1 RepliesI am using try..catch for error handling. I am getting the message displayed as
messagebox.show (ex.tostring)
But it gives very long message.Is it possible just to get only the actual error or I could give my own modified message, based on what ex contains?
I am executing a SQL Server 2000 DTS package using C# by following the code from this article [URL]. once the package is executed I am looping through each step to find out if any step has failed and get info about error if it has failed. I also use this information to find out if the package has succeeded or not (package failed if anyone step has failed).
[Code]....
I am looking at implementing a Web Service API for our product. I have figured out how you go about the general architecture/fault handling within WCF. My question is a more general one of how to design the overall error handling system. For example I have a method called SaveCompany (companyobject). Each company name needs to be unique. Say you tried to save a second company called "ABC Inc.". Would you expect to get back a fault named "DuplicateCompanyFault", or would you expect to get back an error code, or something else? I guess the root of my question is would you prefer to receive faults to handle, error code, or some combination? These services are going to be consumed by multiple different entities outside our company on multiple non-.NET platforms.
View 2 RepliesI am creating function for search data using textbox and button. i want to put an error handling in my code which if the data was not found then it will appear in message box "Data is not found. For your info i am using visual studio and sql 2005. Here is my code and i also attach my picture
Private Sub Search_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnsearch.Click
Me.StaffBindingSource.Filter = "NAME = '" & Me.txtsearch.Text & "'"
[Code].....
I have an issue with handling errors in procedure calls in VB6.
View 6 RepliesI use a standard error handling routine in my methods that looks like the following:
Try
Cursor.Current = Cursors.WaitCursor
Cursor.Current = Cursors.Default
[code].....
I used the following code(with bug):
Code:
For n = 0 To 100
If saveLine(n).Substring(0, 8) = "heading:" Then
cboSelect.Items.Add(saveLine(n).Substring(8))
End If
Next n
The For loop only ran 5 times. It turned out that saveline(5) was shorter then 8 characters, so I changed the code which solved the problem:
Code:
For n = 0 To 100
If saveLine(n).Length > 8 Then
[code]....
VB 2010 neatly exits the for loop when the bug occurs. In this case it was easy for me to pick up the bug, because the combo box was not properly populated. What if it was not obvious that the for loop did not complete? It is quite scary to think that bugs like this are not displayed at run time.
We are developing an application for our shop floor. This program will be tracking material through the shop and we need to capture any errors the program generates, but we don't need to stop the program for all errors. I have some code to do a screen capture and put it in a database with exception.tostring data for debugging.
What we would like to do, is create an exception from the base class, but provide additional properties to allow us to set a severity and a user friendly error message. I would like to encapsulate this in a class that we would call in the catch of a try/catch, set the properties on the class, have the class record the data to the database, then raise the exception to the main program to display only the user friendly message and severity. The main program would then determine the severity and based on the severity stop the program or just display a discreet msg and continue to process.
Does anyone have an example of a custom exception class derived from exception that does something similar, or if I heading in the wrong direction, does anyone have a better solution?
Sometimes when my server is down or busy, I get an error saying "connection timeout" while connecting to MySQL. But with the error the program also crashes. My question is how can I prevent crashing, it would be better to show a msgbox when this happens. (visual basic 2010)here is a screenshot of the error
I use this,
Dim connStr As String = "Database=mydatabase;" & _
"Data Source=datasrc;" & _
[code].....
I have a routine that is called when an unhandled exception occures.It is called by the MyApplication_UnhandledException method in applicationEvents (which handles Me.UnhandledException)
I am looking for some code that manages disects the data provided to generate information that is of benefit to the debugging team.
I just need a good nights sleep, but Im simply reading through a file (2010 data) and for selected teams, accessing the corresponding data for the previous year (2009 data), which is held on a separate file. (I painstakingly input all the 2009 data manually)
ds1.Clear()
cmd1.CommandText = "SELECT * FROM Teams WHERE Team = ?"
cmd1.Parameters.Add(NewSqlCeParameter("Team", (ds.Tables(0).Rows(x) ("Team"))))
cmd1.Prepare()
cmd1.ExecuteNonQuery()
[Code]...
plain how error handling scope works. What I mean by that is if I have a sub called ImportData and in there I have a for loop to go through a list of files and in the for loop I call another sub routine called CheckData. All have catch error in. If a sub has a catch error in where does it go from its call.
Private Sub ImportData
Dim iLoop as Int16
Try
[code].....
I am trying to add some error handling for AppActivate if any error occurs.I initially tried using a try statement and cancelling the sub that calls the function where my AppActivate code is, but that didn't work.I have tried looping it, changing values and everything I know. I have Googled and nothing :S
Here is my I have removed all the error handling I tried to implement, however, this commented msgbox I would like to be included (that is, possible to execute) in any methods you present.
[Code]...
I was just wondering if it is considered overkill to add:
[code]...
To every sub in your project. And what would be the side effects of this if any.
I'm kind of torn between these two error-handling models:Create a boolean Error and a string ErrorMessage property for your object. Catch all exceptions internally in the object's methods and pass the messages along using conditional logic from the caller, ie:
[Code]...
To me, it seems like the same amount of code either way, except that you have property code for the Error and ErrorMessage properties. However, you also can tell when an error occurs without having to check for exceptions. Which pattern should I go with?
Below is a tiny program I modified from an example Microsoft code tutorial. This program simply copies .flac and .mp3 files from one specified folder to another, and if the file is already there it simply does not copy the file. I would like to make 2 changes to the program:
How would I go about making the error handling work (i.e. not crashing the program when an invalid input is made)?Also, a big change I would like to make would be for it to copy the folder structure and all files in the original folder (At the moment, it only copies files that are directly in the original folder, not files that are in folders inside the original folder).
[Code]...
Code:
Public Function ScreenScrapeHtml(ByVal url As String) As String
Dim objRequest As WebRequest = System.Net.HttpWebRequest.Create(url)
[code]...
If it cant reach a URL it will give me this error:
Code:
Webexception was unhandeled:
Dim sr As New StreamReader(objRequest.GetResponse().GetResponseStream())
How I can add some error-handling to this code? Like if it cant reach a URL.