Error Trapping 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. .NET Development Articles and Overviews Upgrading to Microsoft .NET Upgrading to Microsoft .NET Error Handling in Visual Basic .NET Error Handling in Visual Basic .NET Error Handling in Visual Basic .NET ADO.NET for the ADO Programmer Building an N-Tier Application in .NET Calling a .NET Component from a COM Component Calling COM Components from .NET Clients Common .NET Libraries for Developers Comparing System.Xml in Visual Studio .NET to Microsoft.XMLDOM in Visual Studio 6.0 Converting ASP to ASP.NET Creating Classes in Visual Basic .NET Creating Components in .NET Creating a Windows Form User Control Data Binding with Windows Forms and ADO.NET Designing a .NET Application Designing for Web or Desktop? Determining When to Use Windows Installer Versus XCOPY Differences Between Visual Basic 6.0 and .NET Controls Distributed Transactions in Visual Basic .NET Error Handling in Visual Basic .NET Getting Started with Windows Forms Inheritance and Interfaces Inheritance from a Base Class in Microsoft .NET Interacting with Message Queues Introduction to ASP.NET and Web Forms Introduction to Visual Studio .NET Managing Versions of an Application Migrating from the SOAP Toolkit to Web Services Overloading Methods in Visual Basic .NET Performing Drag-and-Drop Operations Raising Events and Responding to Events Replacing API Calls with .NET Framework Classes Structuring a .NET Application For Easy Deployment Understanding and Usi
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 https://msdn.microsoft.com/en-us/library/ms973849.aspx .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 https://msdn.microsoft.com/en-us/library/aa289505(v=vs.71).aspx .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 Basic .NET Deploying Hybrid Visual Basic 6.0 / Visual Basic .NET Applications Deployment Changes in Visual Basic .NET Deploying Assemblies Design an Application Migration
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 - Decision Making VB.Net - Loops VB.Net - Strings VB.Net - Date & Time https://www.tutorialspoint.com/vb.net/vb.net_exception_handling.htm VB.Net - Arrays VB.Net - Collections VB.Net - Functions VB.Net - Subs VB.Net - Classes & http://www.afralisp.net/archive/vba/error.htm Objects VB.Net - Exception 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 - 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 error trapping 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 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 error trapping vb.net 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/Catch block is placed around the code that might generate an exception. Code within a Try/Catch block is referred to as protected code, and the syntax for using Try/Catch looks like the following: Try [ tryStatements ] [ Exit Try ] [ Catch [ exception [ As type ] ] [ When expression ] [ catchStatements ] [ Exit Try ] ] [ Catch ... ] [ Finally [ finallyStatements ] ] End Try You can list do
in many circumstances. For example, suppose you try to open a text file that the user has deleted. When a compiled program has an error like this, an error message isdisplayed and the program ends. Although you cannot predict and write code for every possible type of error, "File Not Found" errors are fairly easy to handle. If you do not write code towork around the error, you can at least provide a message that makes more sense before ending the program. The "On Error" Statement The most common way to handle error conditions is to use Visual Basic's"On Error" statement.The "On Error" statement interrupts the normal flow of your program when an error occurs and begins executing your error handling code. A typical use is as follows :
On Error Goto FileOpenError When this statement is executed, any errors that occur in subsequentstatements cause Visual Basic to stop normal line-by-line execution andjump to the statement labeled as "FileOpenError". Labeling Code Lines Line labels in Visual Basic are similar to the line numbers of early BASIC.In Visual Basic, line labels can include text if you want, but each label mustbe unique. They are followed by a colon (:), as in the following example : Private Sub Form_Load () On Error Goto FileOpenError Open "C:\SOMEFILE.TXT" For Unput As #1 Line Input #1, sData Exit Sub FileOpenError: MsgBox "There was a problem opening the file. Stop for coffee!" End End Sub In the preceding sample code, if the "Open" or "Line Input" statements causean error, the statements starting at the label "FileOpenError" are executed,causing the message to be displayed and ending the program. You should note a few points about the sample code. First, note the locationand style of the error handling routine. It is usually placed near the end of thesubroutine, with the label not indented to indicate a special section of code. Second, and more important, note the "Exit Sub" statement after the "Open" statement. It is necessary to prevent the error handler routine from executingeven when the "Open" statement was successful. Controlling Program Flow After an Error In the preceding code example, you simply end the program if an error occurs. However, you can handle the error in several (better) ways : Exit the subroutine after informing the user of the error, and allow the program to continue running with limited functionality. Resume execution with the next statement following the error. Provide a way for the user to correct the error and retry the offending statement. You can also have multiple labels within a procedure and set the current error handler m