How To Throw Custom Exceptions
Sep 24, 2011I am catching sql exception from databse as shown below.[code]Now I want to throw exception by adding some userfiendly information,Like below.Throw SQLexception + "my message.....".
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Throw System.Exceptions From Within Custom Classes To Calling Code
Jul 9, 2010I Have just been watching a video on throwing Exceptions. Are you supposed to throw System.Exceptions from within your custom classes. to the calling code, Which other way can they communicate. I have read in several places it is bad practice to throw SystemExeptions.
View 3 RepliesWay To Throw Multiple Exceptions
Dec 26, 2009Is there a way to throw multiple exceptions?
i tried to throw an exception in the Finally block but somehow the exception in the Finally block overrides the first exception that i wanted to throw
Thread Safe To Throw And Catch Shared Exceptions?
Jan 25, 2010so 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
Exceptions - Can The "Throw" Statement Exist In A Block With No Try/catch Statement
Oct 5, 2009how 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?
Handling Exceptions Within Custom Functions
Jun 2, 2009All 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 RepliesHow To Catch Unhandled Exceptions In Custom Controls
Jan 5, 2012Is 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.
Create Custom Exceptions To Inherit From System.Exception?
Jan 16, 2010Is the only way to create custom exceptions to inherit from System.Exception?
I wish to create a class that can be thrown as an exception but i do not wish to inherit from System.Exception because i have a base [Object] class in my library which all my classes should inherit from and i wish my custom exception class could also inherit from it.
VS 2008 Handling Exceptions In Custom Control Library
Oct 21, 2009So 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 RepliesThrowing Exceptions For User ? Or Better To Design Custom Error Message Framework?
Nov 10, 2010I never got into detailed error processing too much when I played in VBA/VB6 a lot. Mostly then, if you ran into a user error (such as some input of theirs failing a validation test of some kind), you popped a MsgBox() with some error information and the critical (or warning) icon, and safely aborted out of the code
In .NET, my reading basically points to exceptions as the end-all in error handling. It looks to me that if you know a spot of code where a user can screw up, you're supposed to catch it with either try...catch blocks (for things like data conversions), or standard if...the...else constructs for other things, and then throw a new exception if needed.
Isn't throwing an exception essentially a forced crash of a program in a sense (granted, you get the option of continuing)? Or are exceptions geared specifically for things like data conversion errors and other "things that shouldn't happen", and resume use of MsgBox() and friends for minor user screwups?
Consider the case of where you have a TextBox that is only supposed to accept numeric data (or heck, just a specific set of characters). Barring some other trick that lets you restrict that field (let's just assume it's freeform, programatically), it would seem a bit of a waste to throw new exceptions everytime they type in an invalid character, or even if the error checking doesn't happen until they press a submit button (like on a webpage). Popping a MsgBox() seems more sane in that case.
So what's the straight dope on exceptions and throwing new ones on user errors? How about if your program also exposes a programmatic framework? Bad usage of one of the programmatic functions definitely seems like new exception territory to me.
.net - Why Does Custom HttpResponse Throw Exception On HttpResponse.End()
Jul 27, 2010I'm writing some code in which I need to use my own HttpResponse object to capture the output from a method on another object that takes an HttpResponse as a parameter. The problem is, this other object (which I cannot modify) calls HttpResponse.End(), which causes an "Object reference not set to an instance of an object" exception to be thrown. What can I do about this?
Dim myStringbuilder As New StringBuilder
Dim myStringWriter As New IO.StringWriter(myStringbuilder)
Dim myResponse As New Web.HttpResponse(myStringWriter)
[code].....
Exceptions Must Be Exclusive - Exceptions Will Ever Occur Simultaneously ?
Dec 26, 2009I'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?
View 1 RepliesControl Key + S To Just Throw Up A Messagebox
Mar 8, 2011i have vb 2005 and i dont know how to make Ctrl+S work so that it throws a messagebox on the screen.ive tried a couple of different threads, looking for my answer and i cant seem to find it. its just a simple application, but i want to spice it up a bit with a shortcut to save the info on the screen.i dont want to deal with the saving part yet, but just to get vb to recognize that the user pressed the Ctrl key and the s key in combination.
View 5 RepliesCatch / Handle And Then Again Throw Exception?
Jun 26, 2009I ran into an interesting dilemna today. I have a function that handles information and checks for duplicate values, then returns the next number that is not a duplicate. So, I have something like this:
Public Function GetNextNonDuplicateNumber(NumberToCheck as Long) as Long
//the non-duplicate the function will return
Dim NonDuplicate as Long
'duplicate
If CheckForDuplicate(NumberToCheck) = True Then
Throw New DuplicateException()
[Code] .....
As you can see, I want to handle the exception specifically, but I also want to throw it when I'm done because I want to alert other code outside the function. The problem is that simply throwing it exits out of the function with a null value.
Connect To Oracle Throw The Internet?
Mar 31, 2009[color=#CC66CC]hiiiiiiiiiiiiii every one[/color]
[color=#FF6666]
how can I connect to oracle 10g XE database throw the Internet using Visual Studio .Net? I mean how can I get what I want from my DB using the Internet and what is the compatible version of Visual Studio .Net with oracle 10g XE?[/color] [color=#330033]I wanted to work with oracle Jdevloper but I could not understand anything realy and could not find somthing to show how to start it even :blink:?
Function Throw A Nullreferenceexception Only When Compiled?
Jan 26, 2010This one has me completely confused. I'm using the function below in a .vb file (it's the only function in the file as of right now).
[Code]...
Loop Throw All Usercontrols In A WinForm?
Jul 14, 2011Is it possible to loop throw all usercontrols in a winform.
I wanna run this treatment within a for each and it loop all usercontrols
Usercontrol11 is one of 20 usercontrols existing in a form (usercontrol11,usercontrol12, etc )[code]...
Series Of Commands, Any Of Which May Throw An Exception?
Jun 17, 20101) How is ON ERROR GOTO -1 used? I don't understand the help text.
2) ON ERROR seems to be deprecated. What is the recommended Try...Catch replacement for ON ERROR RESUME NEXT. ie. where I have a series of commands, any of which may throw an exception, and I want to ignore all exceptions yet attempt every command?
ShowDialog Throw Thread Exception
Feb 18, 2011I have written a VB.NET 2.0 code and in my code i am calling class.Showdialog and for that i am getting thread exception. I have mentioned the call stack of the exception. Can any one help me out to resolve this issue. [code]
View 5 RepliesThrow A Message Box If An Error Occurs
May 4, 2009I wanted a Message Box to appear when a file can't be found, for example. I made a Combo Box (ComboBox1) and a button, this is what the code was:[code]If a file can't be found, I want a message box to appear, not an Error Provider, I tried this code, but it did not work:[code]
View 2 RepliesVS 2008 Sending SMS Throw Gmail
Jan 10, 2011I think I have a problem with the provider smtp.Is this the problem? why cant I send SMS? [code]
View 21 RepliesWhy Does Code Throw A Generic Error In GDI+
Jul 28, 2011I'm trying to convert a batch of .pngs to .jpgs, as in this question:
[Code]....
The call to jpg.Save, however, with a "generic error" in GDI+. Originally outside of the innermost Using statement, I moved the call inwards as per this answer, but it didn't change anything. I have verified that newfile contains a valid path, and that the program has write access to the directory. What am I missing?
Why Does This Extension Method Throw A NullReferenceException In .NET
Mar 8, 2010From previous experience I had been under the impression that it's perfectly legal (though perhaps not advisable) to call extension methods on a null instance. So in C#, this code compiles and runs:
// code in static class
static bool IsNull(this object obj) {
return obj == null;
}
[code]....
The debugger stops right there, as if I'd called an instance method. Am I doing something wrong (e.g., is there some subtle difference in the way I defined the extension method between C# and VB.NET)? Is it actually not legal to call an extension method on a null instance in VB.NET, though it's legal in C#?
.net - Exception Handling: Is Finally Executed After Throw?
Oct 16, 2009Assume you have the following code:
Instead of doing:
Try
'
[code].....
.net - IsNumeric Throw FormatException While Evaluating An Object?
Apr 5, 2012I'm working with visual studio 2008 developing software for windows CE 6.0, compact framework.I'm having this "strange?" trouble with isNumeric method. Is there another better way to do this job? Why is getting me an exception? (two in facts...both of type FormatException)
dim tmpStr as object = "Hello"
if isNumeric(tmpStr) then // EXCEPTIONs on this line
// It's a number
else
// it's a string
end if
.net - Why Does XmlDocument.LoadXml Throw System.Net.WebException
Sep 12, 2011Why does System.Xml.XmlDocument.LoadXml method throw System.Net.WebException ?if MSDN was right, LoadXml should at most give me a System.Xml.XmlException.Yet I have weird exceptions like:The underlying connection was closed: The connection was closed unexpectedly.
Dim document As New XmlDocument
document.LoadXml("<!DOCTYPE html PUBLIC ""-//W3C//DTD XHTML 1.0 Transitional//EN"" ""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd""><x></x>")
MsgBox(document.LastChild.Name)
IDE :: Throw Unhandled Exception During Debugging (VB2008)
Apr 24, 2009while my first .net steps I want to understand and test the Method
Private Sub MyApplication_UnhandeledException in ApplicationEvents.vb.
But if I throw an exception the IDE stops and says "unhandled exception" and gives solution tips.
Is it possible to switch off those exception warnings and run through the unhandeled exception handling in ApplicationEvents.vb ?
Throw Exception When Certan Property Or Value Is Negtive?
Feb 9, 2012I'm not getting any errors, or anything I just forgot how to do error checking in the "set" portion of properties
I have 3 Classes, my frmMain,Sales and a Validator Class
Code for the Validator Class:
CODE:
Code for my Sales Class:
CODE:
I need to Throw an Excepton when the Sales price is Zero or negitive and when the trade in allowance is negtive I'm not quite sure how to do that in the Object Oriented Manner.
VS 2008 Anyway To Access Those 'objects' And Just Throw It On Screen?
Oct 22, 2009url...If you check out the images on that website you will notice that in their program, it has the textbox and user icon thing and everything and they have transparencies set.Is there anyway to access those "objects" and just throw it on the screen? How exactly are they doing that? Did they make their own graphics? And if they did, how are they letting it do the transparency, because I know laying a picturebox over a picturebox won't accomplish that.
View 10 Replies.net - Does Not Throw Compiler Error When Setting Dictionary To IList
Jul 6, 2011I am updating a legacy application, and it was reading a dll from another project for a Dictionary(of Guid, String) of items and using them.
The requirements have changed, and the method that was returning the Dictionary is now returning an IList.
This is the odd behavior of this; the intellisense is not throwing a cast error, nor is the compiler. It does not throw an error until runtime when it tries to set the Dictionary to the IList.
Example:
Dim someDictionary As Dictionary(Of Integer, String) = New Dictionary(Of Integer, String)
Dim someList As IList(Of Integer)
someDictionary = someList
why the compiler is not catching this?