Error Handling Techniques In Vb.net
resources Windows Server 2012 resources Programs MSDN subscriptions Overview Benefits Administrators Students Microsoft Imagine Microsoft Student Partners ISV Startups TechRewards Events Community Magazine Forums Blogs Channel 9 Documentation APIs and reference Dev centers Retired content Samples We’re sorry. The content you requested has been removed. You’ll be auto redirected in 1 second. Developing with Visual Studio .NET Articles and Columns Visual Basic .NET Articles Visual Basic .NET Articles Introduction to Exception Handling in Visual Basic .NET Introduction to Exception Handling in Visual Basic .NET Introduction to Exception Handling in Visual Basic .NET Accessing the Registry with Visual Basic .NET Adding New Features with User Controls Advanced Features in Visual Basic .NET and Testing for Scalability Around the World with Visual Basic Aspect-Oriented Programming Asynchronous Execution in Visual Basic .NET Asynchronous Method Execution Using Delegates Automatically Generating Proxy Classes Automatically Generating a Web Service Automating COM+ Administration Best Practices for Windows Forms Applications Building an Attribute Documenter and Viewer Building a Progress Bar that Doesn't Progress Calling All Operators Can I Interest You in 5000 Classes? COM+ and MTS, DCOM and MSMQ, Serialization in .NET Compile Options, Loading Images into PictureBoxes, Deploying .NET Apps, and More Create a Graphical Editor Using RichTextBox and GDI+ Creating A Breadcrumb Control Creating a Five-Star Rating Control Creating and Managing Secondary Threads Creating a Product Search Application Using the eBay SDK and Visual Basic .NET Creating Markup Text in Visual Basic .NET Creating Your Own Dynamic Properties and Preserve Property Settings in Visual Basic .NET Data Binding Radio Buttons to a List Data Binding in Visual Ba
resources Windows Server 2012 resources Programs MSDN subscriptions Overview Benefits Administrators Students Microsoft Imagine Microsoft Student Partners ISV Startups TechRewards Events Community Magazine Forums Blogs Channel 9 Documentation APIs and reference Dev centers Retired content Samples We’re sorry. The content you requested has been removed. You’ll be auto redirected in 1 second. Visual Basic Language Reference Statements Q-Z Statements Q-Z Statements Try...Catch...Finally Statement Try...Catch...Finally Statement Try...Catch...Finally Statement RaiseEvent Statement ReDim Statement REM Statement RemoveHandler Statement Resume Statement Return Statement Select...Case Statement Set Statement https://msdn.microsoft.com/en-us/library/aa289505(v=vs.71).aspx Stop Statement Structure Statement Sub Statement SyncLock Statement Then Statement Throw Statement Try...Catch...Finally Statement Using Statement While...End While Statement With...End With Statement Yield Statement TOC Collapse the table of content Expand the table of content This documentation is archived and is not being maintained. This documentation is archived and is not being maintained. Try...Catch...Finally Statement (Visual Basic) https://msdn.microsoft.com/en-us/library/fk6t46tz.aspx Visual Studio 2015 Other Versions Visual Studio 2013 Visual Studio 2012 Visual Studio 2010 Visual Studio 2008 Visual Studio 2005 Visual Studio .NET 2003 Provides a way to handle some or all possible errors that may occur in a given block of code, while still running code.Syntax Copy Try [ tryStatements ] [ Exit Try ] [ Catch [ exception [ As type ] ] [ When expression ] [ catchStatements ] [ Exit Try ] ] [ Catch ... ] [ Finally [ finallyStatements ] ] End Try PartsTermDefinitiontryStatementsOptional. Statement(s) where an error can occur. Can be a compound statement.CatchOptional. Multiple Catch blocks permitted. If an exception occurs when processing the Try block, each Catch statement is examined in textual order to determine whether it handles the exception, with exception representing the exception that has been thrown. exceptionOptional. Any variable name. The initial value of exception is the value of the thrown error. Used with Catch to specify the error caught. If omitted, the Catch statement catches any ex
VB.Net - Program Structure VB.Net - Basic Syntax VB.Net - Data Types VB.Net - Variables VB.Net - Constants VB.Net - Modifiers VB.Net - Statements VB.Net - Directives VB.Net - Operators VB.Net - https://www.tutorialspoint.com/vb.net/vb.net_exception_handling.htm Decision Making VB.Net - Loops VB.Net - Strings VB.Net - Date & Time VB.Net - Arrays VB.Net - Collections VB.Net - Functions VB.Net - Subs VB.Net - Classes & Objects VB.Net - Exception http://www.vbtutor.net/vb2008/vb2008_lesson20.html Handling VB.Net - File Handling VB.Net - Basic Controls VB.Net - Dialog Boxes VB.Net - Advanced Forms VB.Net - Event Handling VB.Net Advanced Tutorial VB.Net - Regular Expressions VB.Net - Database Access VB.Net error handling - Excel Sheet VB.Net - Send Email VB.Net - XML Processing VB.Net - Web Programming VB.Net Useful Resources VB.Net - Quick Guide VB.Net - Useful Resources VB.Net - Discussion Selected Reading Developer's Best Practices Questions and Answers Effective Resume Writing HR Interview Questions Computer Glossary Who is Who VB.Net - Exception Handling Advertisements Previous Page Next Page An exception is a problem that arises error handling techniques during the execution of a program. An exception is a response to an exceptional circumstance that arises while a program is running, such as an attempt to divide by zero. Exceptions provide a way to transfer control from one part of a program to another. VB.Net exception handling is built upon four keywords: Try, Catch, Finally and Throw. Try: A Try block identifies a block of code for which particular exceptions will be activated. It's followed by one or more Catch blocks. Catch: A program catches an exception with an exception handler at the place in a program where you want to handle the problem. The Catch keyword indicates the catching of an exception. Finally: The Finally block is used to execute a given set of statements, whether an exception is thrown or not thrown. For example, if you open a file, it must be closed whether an exception is raised or not. Throw: A program throws an exception when a problem shows up. This is done using a Throw keyword. Syntax Assuming a block will raise an exception, a method catches an exception using a combination of the Try and Catch keywords. A Try/
error-free program can run smoothly and efficiently, otherwise all sorts of problems occur such as program crash or system hang. Errors often occur due to incorrect input from the user. For example, the user might make the mistake of attempting to enter a text (string) to a box that is designed to handle only numeric values such as the weight of a person, the computer will not be able to perform arithmetic calculation for text therefore will create an error. These errors are known as synchronous errors. Therefore a good programmer should be more alert to the parts of program that could trigger errors and should write errors handling code to help the user in managing the errors. Writing errors handling code should be considered a good practice for Visual Basic programmers, so do try to finish a program fast by omitting the errors handling code. However, there should not be too many errors handling code in the program as it create problems for the programmer to maintain and troubleshoot the program later. Visual Basic 2008 has improved a lot in built-in errors handling compared to Visual Basic 6. For example, when the user attempts to divide a number by zero, Vb2008 will not return an error message but gives the 'infinity' as the answer (although this is mathematically incorrect, because it should be undefined) 20.2 Using On Error GoTo Syantax Visual Basic 2008 still supports the VB6 errors handling syntax, that is the On Error GoTo program_label structure. Although it has a more advanced error handling method, we shall deal with that later.We shall now learn how to write errors handling code in VB2008. The syntax for errors handling is On Error GoTo program_label where program_label is the section of code that is designed by the programmer to handle the error committed by the user. Once an error is detected, the program will jump to the program_label section for error handling.
Example 20.1: Division by Zero In this example, we will deal with the error of entering non-numeric data into the textboxes that suppose to hold numeric values. The program_label here is error_hanldler. when the user enter a non-numeric values into